Clinical outcome of protocol based image (MRI) guided adaptive brachytherapy combined with 3D conformal radiotherapy with or without chemotherapy in patients with locally advanced cervical cancer

Global Review of Tools Evaluating Quality of Life in Cervical Cancer Survivors Treated With Chemoradiation Therapy

Purpose

This systematic review aimed to identify and compare tools used to evaluate quality of life (QoL) after pelvic radiation for cervical cancer and to describe variations in results within commonly used instruments. This review hypothesized regional preferences in the selection of these tools and an absence of uniformity in their application globally.

Methods and Materials

A comprehensive search of 6 databases was conducted between the inception of each included database and June 14, 2023, focusing on studies evaluating the QoL of patients with cervical cancer during and after radiation. Excluded were studies involving cancers originating outside the cervix, those not exclusively undergoing radiation or chemoradiation therapy, such as patients who have undergone surgery, and non-English studies.

Results

Ultimately, 229 studies covering 25,693 patients and 51 countries were identified. Most studies were conducted in Asia (35.6%) and Europe (32.9%). Ninety-nine QoL instruments were identified, not including those that were specific to a single study. The European Organisation for Research and Treatment of Cancer QoL Questionnaire Core 30 (20.5%) and the European Organization for Research and Treatment of Cancer (EORTC) QoL questionnaire cervical cancer module (16.0%) were the most commonly used; however, US-based studies primarily used the Functional Assessment of Cancer Therapy-General surveys. Furthermore, there was significant variability in the timelines of survey usage in relation to when treatment was completed, further limiting the comparisons that can be made. Of the 127 studies that reported data on the time points after completion of treatment at which QoL was measured, 72.4% measured QoL within 1 year of treatment completion, and 48.8% measured QoL >1 year after treatment completion, with some studies using multiple time points for their research.

Conclusions

This study revealed a fragmented landscape with significant variability in QoL survey use, limiting the generalizability and usefulness of these results to drive meaningful change. There is a need for a global standardized method to evaluate QoL after treatment of cervical cancer with radiation therapy for comparison across regions. Simplified tools may assist with the broader collection of data, which may lead to advancements for improvement of the QoL of these patients.

The influence of time and implants in high-dose rate image-guided adaptive brachytherapy for locally advanced cervical cancer

PURPOSE

To compare the clinical outcomes of two different schedules of modern image-guided adaptive brachytherapy (IGABT) in patients underwent chemoradiotherapy (CCRT) and high-dose rate (HDR) brachytherapy (BT) for locally advanced cervical cancer treated (LACC) METHODS AND MATERIALS: Data from medical records of all consecutive patients with histologically proven cervical cancer (FIGO 2018 stage IB-IVA) treated by HDR-BT after CCRT at our institution between 2016 and 2021 were reviewed.

RESULTS

Two hundred and 8 patients with LACC FIGO 2018 stages (IB 20.7%; II 26.5%, III 51%, IVA 1.9%) underwent brachytherapy at our institution. Depending on initial clinical features of disease and the clinical response to CCRT, HDR-BT was delivered with one implant (BT1i) or two implants (BT2i) in 39% and 61% of patients respectively. FIGO stages (≥IIB) were 63% vs. 78% for BT1i and BT2i patient group respectively. Combined brachytherapy technique [endocavitary/interstitial (IC/IS)] was required in 14.8% vs. 68.5% for BT1i and BT2i respectively. With a median follow-up of 32.5 months (95% confidence interval, [29.7-35.8]), local relapse was observed in sixteen patients: 8 patients (3.8%) had local (exclusive) relapse and 8 patients (3.8%) had locally persistent and progressive disease, without significant difference for each BT modality group (p = 0.27), even if BT2i group had more aggressive initial disease. The estimated 3-year disease free survival and overall survival for the entire population was 69% (95% confidence interval, [62-75%]) and 88% (95% confidence interval, [82-92%]) respectively. There was a significant difference in the incidence of global toxicity grade G≥2 in favour to the BT2i group (p = 0.026).

CONCLUSIONS

HDR brachytherapy delivered with a long time interval between fractions, two implants, and combined IC/IS brachytherapy is the best way to ensure local control and to perform IGABT with low toxicity, even in advanced stages of disease.

Image guided cervical brachytherapy practice patterns: 2023/2024 survey of the American brachytherapy society

BACKGROUND

An update of the 2007 and 2014 surveys of the American Brachytherapy Society (ABS) will elucidate current practice patterns of cervical cancer brachytherapy.

METHODS

A 40-question survey was sent to all ABS members in June-July 2023 and February 2024; 167 responses were received, with 140 used for analysis. Results were compared to the 2014 survey using chi-squared testing. Multivariable logistic regression was used to calculate adjusted odds ratios (aOR) with 95% confidence intervals (CI) for outcomes of interest.

RESULTS

Compared to 2014, MRI use for treatment planning of the first brachytherapy fraction increased from 34% to 63% (p < 0.001), prescription to the high-risk clinical target volume (HR-CTV) increased from 52% to 94% (p < 0.001), while Point A prescription decreased from 42% to 16% (p < 0.001). Additionally, procedural guidance with ultrasound significantly increased (79% vs. 32%, p < 0.001) along with the use of interstitial needles (always or nearly always, >80%) (29% vs. 4%, p < 0.001). MRI availability around the time of procedure was the largest challenge to incorporating MRI into brachytherapy treatment planning. Compared to those with MRI access reserved specifically for Radiation Oncology, respondents with shared-access or out-of-department MRI were less likely to obtain treatment planning MRIs for each brachytherapy fraction (22% vs. 75%; aOR 0.10 [95% CI, 0.03-0.30], p < 0.001).

CONCLUSION

For cervix cancer brachytherapy there has been significant increase in the use of MRI-based volumetric brachytherapy treatment planning, ultrasound guidance during procedures and the addition of interstitial needles. These advancements in practice patterns are congruent with published consensus guidelines and ongoing training initiatives. However, MRI access and lack of easy availability continue to be significant challenges for optimizing cervix brachytherapy.

Factors Affecting D90 High-risk Clinical Target Volumes (HR-CTV dose) of Intracavitary and Interstitial Brachytherapy in Locally Advanced Cervical Cancer

AIMS

Intracavitary brachytherapy alone covers a limited target volume; however, intracavitary and interstitial brachytherapy (IC/IS) can increase the dose coverage. We aim to assess the factors that impact D90 high-risk clinical target volume (HR-CTV) dose. We also assess clinical outcomes and toxicities for 3D image-based brachytherapy.

MATERIALS AND METHODS

We included a total of 424 cervical cancer patients with FIGO stage IB1 to IVA who received chemoradiation and high-dose-rate brachytherapy between 2014 and 2023. Target delineation was per GEC-ESTRO guidelines with the aim to achieve total dose of ≥85 Gy (D90 HR-CTV) in equivalent dose (EQD2). Implantation, tumour size, lateral extension, and HR-CTV volume were analysed.

RESULTS

The median follow-up time was 24 months (range 1-107). The overall 2-year local control, progression-free survival, and overall survival rate were 90.3%, 75%, and 95.5%, respectively. Of 424 patients, 86.8% received a total dose of at least 85 Gy of D90 HR-CTV in EQD2. In multivariate analysis, IC/IS brachytherapy and HR-CTV volume were significant factors associated with HR-CTV D90 ≥ 85Gy in EQD2 (P = 0.012 and P = 0.000, respectively). Subgroup analysis of patients with HR-CTV volume >35 ml found that IC/IS was a significant factor in achieving HR-CTV D90 ≥ 85Gy in EQD2 (P = 0.017). At the median follow-up, patients with D90 HR-CTV ≥85 Gy achieved local control rates of 72.08% in small volume (<20 cm3) group, 68.42% in intermediate volume (21-30 cm3) group, 71.68% in high intermediate volume (31-60 cm3) and 17.67% in larger volume (>60 cm3) group (P = 0.005). Grade 3 toxicities including proctitis, cystitis, and vaginal stenosis were 7.1%, 1.9% and 0.2%, respectively.

CONCLUSION

IC/IS brachytherapy may be used in patients with HR-CTV volumes greater than 35 ml to achieve total doses of D90 HR-CTV ≥85 Gy in EQD2. IC/IS brachytherapy also provide good local control with favorable toxicity profile.

Development and implementation of a 3d-HDR brachytherapy program for cervical cancer in a sub-Saharan African centre

BACKGROUND

Cervical cancer is the second most common cancer among women in Nigeria where, the gap between need for, and access to, radiation therapy including brachytherapy is significant. This report documents the implementation of the first three-dimensional high-dose-rate (3D-HDR) brachytherapy service for cervical cancer in Nigeria.

PURPOSE

This report details the steps taken to implement the 3D-HDR brachytherapy program, the challenges faced, and the adaptive strategies employed to overcome them. Our objective is to provide a guide for teams and centers in similar resource-restricted settings to implement 3D-HDR brachytherapy services, by leveraging our shared experience and lessons learned.

METHOD AND METERIALS

The implementation process required investment in infrastructure: creating a dedicated brachytherapy suite equipped with modern technology; and human capital: conducting both virtual and hands-on training for staff; and involving international experts during the initial treatment phases. Quality assurance protocols were established to ensure the accuracy and safety of treatments. Key adaptations included extensive remote training, international experts flying in for the initiation phase, and preemptively re-ordering the radioisotope to prevent delays.

RESULTS

The 3D-HDR brachytherapy program was successfully implemented, with five cases treated in the first 2 months despite challenges such as high equipment costs, expertise and proficiency needs, and source replacement delays. Continuous training and quality assurance measures ensured the program's sustainability and effectiveness.

CONCLUSIONS

Implementing a 3D-HDR brachytherapy program in a system with restricted resources is possible with thorough planning, flexible strategies, and adaptive measures. We document our experience to provide insights for other institutions aiming to establish similar programs. Collaboration and innovative financial strategies are essential for ensuring sustainable access to cancer treatment in the region. Strategies such as remote training and proactive resource management, are critical for overcoming implementation barriers.

Evaluation of plan quality, safety, and toxicity of brachytherapy for locally advanced cervical cancer in an Australian setting following changes in prescription and applicator design

INTRODUCTION

Chemoradiotherapy with MRI-guided brachytherapy boosts is the standard of care for locally advanced cervical cancer. Data from the RetroEMBRACE and EMBRACE I trials provide dose-response curves for target volumes and OAR. This study evaluated plan quality, safety and toxicity following escalation of the CTV_HR D90 prescription from 80-90 Gy to 85-95 Gy for two different applicator designs.

METHODS

A retrospective dosimetric plan quality review was undertaken for consecutively treated locally advanced cervical cancer brachytherapy boosts between 2017 and 2022, and the relationships between implant total reference air kerma (TRAK), CTV_HR volume and vaginal dose were investigated. Safety and ≤grade 3 toxicity results were evaluated.

RESULTS

Seventy patients were identified. All patients received a CTV_HR D90 dose >85 Gy and rectum D2cm3 of <75 Gy, while 88.6% of patients received a bladder D2cm3 <90 Gy. Needles were used in 48.6% of patients, and the mean percentage needle TRAK was 38.2%. Increasing the percentage of needle TRAK decreased vaginal TRAK. Sixty-three patients had more than 12 months of follow-up (median 27 months). From this cohort, grade 3 or higher toxicity for vaginal, genitourinary, gastrointestinal and fistula events were seen in 3.2%, 1.6%, 0% and 3.2% of patients, respectively.

CONCLUSION

Increased dose prescriptions and a change of applicator design were successfully adopted into an Australian practice. Applicator design and interstitial needle use affect the plan quality and ability to meet OAR dose constraints following target dose escalation. No safety concerns with needle use or dose escalation were identified.

External beam radiotherapy followed by image-guided adaptive brachytherapy in locally advanced cervical cancer: a multicenter retrospective analysis

PURPOSE

To evaluate oncological outcomes and toxicities in patients with locally advanced cervical cancer (LACC) treated with concurrent chemoradiotherapy followed by image-guided adaptive brachytherapy at two Italian centres.

MATERIAL AND METHODS

A retrospective analysis was conducted on 122 patients with LACC treated between 2010 and 2022. Primary endpoints were local control (LC), pelvic control (PC), and nodal control (NC). Secondary endpoints included disease-free survival (DFS), metastasis-free survival (MFS), overall survival (OS), and late toxicity. Correlations between patient characteristics and oncological outcomes were conducted.

RESULTS

Brachytherapy planning was CT and MRI-based in 88 (72.1%) and 34 patients (27.9%), respectively. The mean total dose (EQD2) delivered to high-risk clinical target volume was 82 Gy. Overall treatment time was ≤ 50 days and > 50 days in 48 (39.3%) and 74 patients (60.7%), respectively. At a mean follow up of 101 months, 3 and 5-year LC rates were 87% and 85%, respectively. Five-year PC and NC rates were 77% and 85.1%. Five-year DFS and OS were 61% and 65.4%, respectively, with significant correlations between these outcomes and FIGO stage and nodal status at diagnosis. Gastrointestinal, genitourinary and vaginal adverse effects were the most reported late toxicities and 8 (6.5%) grade 3-5 events were observed. 32 patients (26.2%) had vaginal stenosis and it was significantly related to 3D imaging used for brachytherapy planning.

CONCLUSIONS

The study confirmed the efficacy and safety of chemoradiotherapy and IGABT for LACC. Full implementation of MRI treatment planning and interstitial techniques could further enhance personalized treatment and outcomes.

Dosimetric evaluation of adaptive planning for five-fraction gynecologic template-based interstitial brachytherapy

PURPOSE

The purpose of this work was to evaluate whether inter-fraction imaging and replanning enhance treatment delivery adherence to clinical planning objectives in the context of a 5-fraction template-based interstitial brachytherapy (TISB) approach for gynecologic cancer treatment.

METHODS AND MATERIALS

This retrospective study analyzed nineteen patients who underwent 5 fractions of interstitial brachytherapy over 3 days using the Syed-Neblett template. A verification CT scan was acquired for applicator assessment and reviewed by a radiation oncologist and medical physicist before each fraction. Eleven patients required replanning at least once during the treatment course. Replanning on the verification CT scan consisted of generating new target and organ-at-risk contours, digitizing catheter positions, and optimizing source dwell times to meet planning objectives. Dwell times and positions from the initial treatment plan were evaluated on the new contours to assess the dose that would have been delivered without replanning (nonadapted). Significance of nonadapted versus adapted dose differences were evaluated using a 2-sided Wilcoxon sum rank test.

RESULTS

The average (min, max) change in dose (Gy) between the clinically delivered plans and the nonadapted plans were HR-CTV D90%: -6.5 (-0.6, -15.1), HR-CTV D98%: -6.5 (-0.4, -12.6), Bladder D2cc: -0.5 (0.0, -2.8), Bowel D2cc: -0.8 (0.0, -3.2), Rectum D2cc: -1.1 (0.0, -11.5), Sigmoid D2cc: -1.4 (-0.1, -5.4). Dosimetric changes in HR-CTV coverage were significantly improved with replanning while organ-at-risk differences were nonsignificant (p > 0.05). Fraction 3 was the most common fraction indicated for replanning.

CONCLUSIONS

Replanning template-based interstitial brachytherapy can improve target coverage and adherence to planning goals.

Personalized strategies for brachytherapy of cervix cancer

Among most tailored approaches in radiation oncology, the development of brachytherapy for the treatment of cervical cancer patients has benefited from various technological innovations. The development of 3D image-guided treatments was the first step for treatment personalization. This breakthrough preceded practice homogenization and validation of predictive dose and volume parameters and prognostic factors. We review some of the most significant strategies that emerged from the ongoing research in order to increase personalization in uterovaginal brachytherapy. A better stratification based on patients and tumors characteristics may lead to better discriminate candidates for intensification or de-escalation strategies, in order to still improve patient outcome while minimizing the risk of treatment-related side effects.

Clinical Outcome Comparison between CT-Guided Versus all MRI-Guided Scenarios in Brachytherapy for Cervical Cancer: A Single-Institute Experience

OBJECTIVES

Image-guided adaptive brachytherapy (IGABT) is the standard of care for patients with cervical cancer. The objective of this study was to compare the treatment outcomes and adverse effects of computed tomography (CT)-guided and magnetic resonance imaging (MRI)-guided scenarios.

MATERIALS AND METHODS

Data of patients with cervical cancer treated using external beam radiotherapy followed by IGABT from 2012 to 2016 were retrospectively reviewed. CT-guided IGABT was compared with the three modes of MRI-guided IGABT: pre-brachytherapy (MRI Pre-BT) without applicator insertion for fusion, planning MRI with applicator in-place in at least 1 fraction (MRI ≥1Fx), and MRI in every fraction (MRI EveryFx). Patient characteristics, oncologic outcomes, and late radiation toxicity were analyzed using descriptive, survival, and correlation statistics.

RESULTS

Overall, 354 patients were evaluated with a median follow-up of 60 months. The 5-year overall survival (OS) rates were 61.5%, 65.2%, 54.4%, and 63.7% with CT-guided, MRI PreBT, MRI ≥1Fx, and MRI EveryFx IGABT, respectively with no significant differences (p = 0.522). The 5-year local control (LC) rates were 92.1%, 87.8%, 80.7%, and 76.5% (p = 0.133), respectively, with a significant difference observed between the CT-guided and MRI ≥1Fx (p = 0.018). The grade 3-4 late gastrointestinal toxicity rates were 6% in the CT-guided, MRI ≥1Fx, and MRI EveryFx, and 8% in MRI PreBT. The grade 3-4 late genitourinary toxicity rates were 4% in the CT-guided, 2% in MRI PreBT, 1% in MRI ≥1Fx, and none in MRI EveryFx. No significant differences were observed in the oncologic and toxicity outcomes among MRI PreBT, MRI ≥1Fx, and MRI EveryFx.

CONCLUSIONS

CT-guided IGABT yielded an acceptable 5-year OS, LC, and toxicity profile compared with all MRI scenarios and is a potentially feasible option in resource-limited settings.

Dose escalation with stereotactic body radiotherapy for cervical cancer treatment

BACKGROUND

Dose escalation with brachytherapy after pelvic irradiation is standard for treating cervical cancer. Its application can be impossible for some patients. Dose escalation with SBRT is widely used with high local control and acceptable toxicity rates in different body parts. The study enrolled patients who underwent SBRT treatment for dose escalation in the cervix.

METHODS

Patients who were pathologically diagnosed and treated with cervical SBRT after definitive CRT were included in the study. A total of 30 Gy in 5 fractions for the high-risk volume was prescribed. The first response evaluation was performed three months after the completion of treatment. Treatment toxicity was documented according to the RTOG-EORTC scale. Oncological outcomes and toxicity were assessed.

RESULTS

Between 02.2019 and 05.2023, 40 patients were treated with an SBRT boost after pelvic irradiation. The median follow-up time was 16 months (7-44 months). The median HR CTV was 47 cc (8,3-168,2 cc). There were 39 patients who achieved a complete response and one who achieved a partial response in the third month after treatment. There were two local or two regional recurrences. The 1-year metastasis-free survival was 88%, and the 1-year progression-free survival was 88%. During the follow-up period, one grade 3 gastrointestinal side effect was observed.

CONCLUSIONS

SBRT which has low toxicity and reasonable locoregional control rates in a short follow-up period, may be an option for dose escalation in brachytherapy-ineligible cervical cancer patients.

Long term clinical outcomes of cervical cancer patients who were recommended surgery but did not undergo it: A SEER database study

BACKGROUND

This study analyzed the long-term clinical outcomes of cervical cancer patients recommended surgery but who did not undergo it using the Surveillance, Epidemiology, and End Results (SEER) database. The aim was to identify the subgroups with comparable overall survival (OS) and cancer-specific survival (CSS) through stratified analysis.

METHODS

Cases of cervical cancer were retrieved from SEER database using SEER*Stat software. This included patients in the non-surgery group (recommended surgery but did not undergo it), and a reference surgery group. Propensity score matching balanced differences between the non-surgery and surgery groups. Stratified analysis and log-rank tests were used to identify subgroups within the non-surgery group with comparable OS and CSS to the surgery group.

RESULTS

A total of 30,807 cervical cancer patients were included in the OS and CSS analysis. In the matched cohort (n = 1278), patients in the non-surgery group had significantly lower 5-year CSS (63.2 % vs. 80.1 %, P < 0.001) and 5-year OS (59.0 % vs. 78.0 %, P < 0.001). However, within the matched cohort, there was no statistically significant difference in OS and CSS between the non-surgery and surgery groups in subgroups diagnosed during 2010-2014 (P = 0.064, P = 0.182), 2015-2020 (P = 0.122, P = 0.518), T2 stage (P = 0.139, P = 0.052), T3 stage (P = 0.502, P = 0.317), or with distant metastasis (M1) (P = 0.411, P = 0.520).

CONCLUSION

Patients in the non-surgery group generally exhibited lower long-term clinical outcomes compared to those in the surgery group. However, with advancements in non-surgical treatment techniques, particularly notable in patients with T2, T3, and M1 stages, these differences are gradually diminishing.

Nerve-Sparing Laparoscopic Radical Hysterectomy (nsLRH) without Adjuvant Therapy in FIGO Stage IB3 Cervical Cancer Patients: Surgical Technique and Survival Outcomes

(1) Background: In 2018 FIGO reclassified tumors confined to the cervix larger than 4 cm as stage IB3. Although concurrent CTRT has been the standard of care and surgery the alternative, optimal management remains controversial due to the lack of direct comparison between surgery and CTRT. (2) Methods: This prospective observational study investigated the efficacy, safety and oncologic outcomes of nerve-sparing laparoscopic radical hysterectomy (nsLRH) for FIGO stage IB3 cervical cancer patients (IB3). From 2009 to 2023, IB3 patients underwent laparoscopic pelvic lymphadenectomies with frozen section analysis, followed by a nsLRH if the lymph nodes were tumor-free. No uterine manipulator was used and the vaginal cuff was sealed before retrieving the specimen. Intermediate-risk patients were under close observation without adjuvant therapy. Outcomes were monitored until 2023. (3) Results: During the study period, 74 IB3 patients were treated. Sixty-eight (91.9%) underwent a nsLRH. A complete resection with negative margins was achieved in all cases. At a median of 68 months of follow-up, the disease-free survival (DFS) rate was 89.7% and the overall survival (OS) rate was 93.1%. The overall complication rate was 23.5% and there were no grade 4-5 complications. (4) Conclusions: In patients with IB3 cervical cancer, a nsLRH is safe and effective. While awaiting the results from ongoing randomized trials, these findings support nsLRH as a viable treatment.

Patient Experiences of Brachytherapy for Locally Advanced Cervical Cancer: Hearing the Patient Voice Through Qualitative Interviews

PURPOSE

Brachytherapy for gynecological cancer is reported to cause pain, anxiety, and distress with no clear guidance for optimizing patient experiences. The aim of this study was to explore patient experiences of brachytherapy and views on improvement.

METHODS AND MATERIALS

Semistructured interviews were undertaken with patients who had received brachytherapy for locally advanced cervical cancer. Two cohorts were recruited: cohort 1 had recently had brachytherapy, and cohort 2 was a year post brachytherapy. Four recruitment sites were selected, where brachytherapy is given in different ways, some with short day case procedures and others having 1 or 2 overnight stays with applicators in place. Consecutive patients were invited to interview. Participants were asked to retell their brachytherapy story, with views on their care and ideas for improvement. Interviews were audio recorded, transcribed, and data analyzed following Braun and Clarke's method for reflexive thematic analysis.

RESULTS

Thirty-five interviews were conducted (20 in cohort 1 and 15 in cohort 2). Participant's ages ranged from 28 to 87 years. The interview duration ranged from 22 to 78 minutes. Difficult and traumatic experiences were reported, including periods of severe pain and perceptions of poor care. However, some participants described positive experiences and what went well. Three themes were developed: (1) how the patient got through it, (2) unpleasantness, discomfort, and the aftermath, and (3) emotional consequences and trauma. Some aspects of medium and long duration brachytherapy were found to be more problematic compared with short duration brachytherapy. Exploring experiences at 1-year post brachytherapy has provided insights into the long-lasting impact of brachytherapy experiences.

CONCLUSIONS

Hearing the patient voice has demonstrated that further work is needed to improve patient care in modern brachytherapy techniques using different regimens and durations, to minimize difficult and traumatic patient experiences. Study insights will inform future work to develop clinical care recommendations.

Dosimetric and toxicity comparison between Syed-Neblett and Fletcher-Suit-Delclos Tandem and Ovoid applicators in high dose rate cervix cancer brachytherapy

PURPOSE

To compare patient and tumor characteristics, dosimetry, and toxicities between interstitial Syed-Neblett and intracavitary Fletcher-Suit-Delclos Tandem and Ovoid (T&O) applicators in high dose rate (HDR) cervical cancer brachytherapy.

METHODS

A retrospective analysis was performed for cervical cancer patients treated with 3D-based HDR brachytherapy from 2011 to 2023 at a single institution. Dosimetric parameters for high-risk clinical target volume and organs at risk were obtained. Toxicities were evaluated using the Common Terminology Criteria for Adverse Events version 5.0.

RESULTS

A total of 115 and 58 patients underwent Syed and T&O brachytherapy, respectively. Patients treated with Syed brachytherapy were more likely to have larger tumors and FIGO stage III or IV disease. The median D2cc values to the bladder, small bowel, and sigmoid colon were significantly lower for Syed brachytherapy. Patients treated with Syed brachytherapy were significantly more likely to be free of acute gastrointestinal (44% vs. 21%, p = 0.003), genitourinary (58% vs. 36%, p = 0.01), and vaginal toxicities (60% vs. 33%, p = 0.001) within 6 months following treatment compared to patients treated with T&O applicators. In contrast, Syed brachytherapy patients were more likely to experience late gastrointestinal (68% vs. 49%, p = 0.082), genitourinary (51% vs. 35%, p = 0.196), and vaginal toxicities (70% vs. 57%, p = 0.264).

CONCLUSIONS

Syed-Neblett and T&O applicators are suitable for HDR brachytherapy for cervical cancer in distinct patient populations. Acute toxicities are more prevalent with T&O applicators, while patients treated with Syed-Neblett applicators are more likely to develop late toxicities.

MRI-guided dynamic risk assessment in cervical cancer based on tumor hypoxia at diagnosis and volume response at brachytherapy

BACKGROUND AND PURPOSE

Improvements in treatment outcome for patients with locally advanced cervical cancer (LACC) require a better classification of patients according to their risk of recurrence. We investigated whether an imaging-based approach, combining pretreatment hypoxia and tumor response during therapy, could improve risk classification.

MATERIAL AND METHODS

Ninety-three LACC patients with T2-weigthed (T2W)-, dynamic contrast enhanced (DCE)- and diffusion weighted (DW)-magnetic resonance (MR) images acquired before treatment, and T2W- and, for 64 patients, DW-MR images, acquired at brachytherapy, were collected. Pretreatment hypoxic fraction (HFpre) was determined from DCE- and DW-MR images using the consumption and supply-based hypoxia (CSH)-imaging method. Volume regression at brachytherapy was assessed from T2W-MR images and combined with HFpre. In 17 patients with adequate DW-MR images at brachytherapy, the apparent diffusion coefficient (ADC), reflecting tumor cell density, was calculated. Change in ADC during therapy was combined with volume regression yielding functional regression as explorative response measure. Endpoint was disease free survival (DFS).

RESULTS

HFpre was the strongest predictor of DFS, but a significant correlation with outcome was found also for volume regression. The combination of HFpre and volume regression showed a stronger association with DFS than HFpre alone. Patients with disease recurrence were selected to either the intermediate- or high-risk group with a 100 % accuracy. Functional regression showed a stronger correlation to HFpre than volume regression.

CONCLUSION

The combination of pretreatment hypoxia and volume regression at brachytherapy improved patient risk classification. Integration of ADC with volume regression showed promise as a new tumor response parameter.

A Novel Positive-Contrast Magnetic Resonance Imaging Line Marker for High-Dose-Rate (HDR) MRI-Assisted Radiosurgery (MARS)

Magnetic resonance imaging (MRI) can facilitate accurate organ delineation and optimal dose distributions in high-dose-rate (HDR) MRI-Assisted Radiosurgery (MARS). Its use for this purpose has been limited by the lack of positive-contrast MRI markers that can clearly delineate the lumen of the HDR applicator and precisely show the path of the HDR source on T1- and T2-weighted MRI sequences. We investigated a novel MRI positive-contrast HDR brachytherapy or interventional radiotherapy line marker, C4:S, consisting of C4 (visible on T1-weighted images) complexed with saline. Longitudinal relaxation time (T1) and transverse relaxation time (T2) for C4:S were measured on a 1.5 T MRI scanner. High-density polyethylene (HDPE) tubing filled with C4:S as an HDR brachytherapy line marker was tested for visibility on T1- and T2-weighted MRI sequences in a tissue-equivalent female ultrasound training pelvis phantom. Relaxivity measurements indicated that C4:S solution had good T1-weighted contrast (relative to oil [fat] signal intensity) and good T2-weighted contrast (relative to water signal intensity) at both room temperature (relaxivity ratio > 1; r2/r1 = 1.43) and body temperature (relaxivity ratio > 1; r2/r1 = 1.38). These measurements were verified by the positive visualization of the C4:S (C4/saline 50:50) HDPE tube HDR brachytherapy line marker on both T1- and T2-weighted MRI sequences. Orientation did not affect the relaxivity of the C4:S contrast solution. C4:S encapsulated in HDPE tubing can be visualized as a positive line marker on both T1- and T2-weighted MRI sequences. MRI-guided HDR planning may be possible with these novel line markers for HDR MARS for several types of cancer.

Integration of Ultrasound in Image-Guided Adaptive Brachytherapy in Cancer of the Uterine Cervix

Cervical cancer continues to be a public health concern, as it remains the second most common cancer despite screening programs. It is the third most common cause of cancer-related death for women, and the majority of cases happen in developing nations. The standard treatment for locally advanced cervical cancer involves the use of external beam radiation therapy, along with concurrent chemotherapy, followed by an image-guided adaptive brachytherapy (IGABT) boost. The five-year relative survival rate for European women diagnosed with cervical cancer was 62% between 2000 and 2007. Updated cervical cancer treatment guidelines based on IGABT have been developed by the Gynecological working group, which is composed of the Group Européen de Curiethérapie-European Society for Therapeutic Radiology and Oncology. The therapeutic strategy makes use of three-dimensional imaging, which can be tailored to the target volume and at-risk organs through the use of computed tomography or magnetic resonance imaging. Under anaesthesia, the brachytherapy implantation is carried out. Ultrasonography is utilised to assess the depth of the uterine cavity and to facilitate the dilation of the uterine canal during the application insertion. In this study, we examine data from the international literature regarding the application of ultrasound in cervical cancer brachytherapy.

Prospective validation of a machine learning model for applicator and hybrid interstitial needle selection in high-dose-rate (HDR) cervical brachytherapy

PURPOSE

To Demonstrate the clinical validation of a machine learning (ML) model for applicator and interstitial needle prediction in gynecologic brachytherapy through a prospective clinical study in a single institution.

METHODS

The study included cervical cancer patients receiving high-dose-rate brachytherapy using intracavitary (IC) or hybrid interstitial (IC/IS) applicators. For each patient, the primary radiation oncologist contoured the high-risk clinical target volume on a pre-brachytherapy MRI, indicated the approximate applicator location, and made a clinical determination of the first fraction applicator. A pre-trained ML model predicted the applicator and IC/IS needle arrangement using tumor geometry. Following the first fraction, ML and radiation oncologist predictions were compared and a replanning study determined the applicator providing optimal organ-at-risk (OAR) dosimetry. The ML-predicted applicator and needle arrangement and the clinical determination were compared to this dosimetric ground truth.

RESULTS

Ten patients were accrued from December 2020 to October 2022. Compared to the dosimetrically optimal applicator, both the radiation oncologist and ML had an accuracy of 70%. ML demonstrated better identification of patients requiring IC/IS applicators and provided balanced IC and IC/IS predictions. The needle selection model achieved an average accuracy of 82.5%. ML-predicted needle arrangements matched or improved plan quality when compared to clinically selected arrangements. Overall, ML predictions led to an average total improvement of 2.0 Gy to OAR doses over three treatment fractions when compared to clinical predictions.

CONCLUSION

In the context of a single institution study, the presented ML model demonstrates valuable decision-support for the applicator and needle selection process with the potential to provide improved dosimetry. Future work will include a multi-center study to assess generalizability.

Evaluating outcomes and toxicities for a newly implemented MRI-based brachytherapy program for cervical cancer

OBJECTIVE

We report an updated analysis of the outcomes and toxicities of MRI-based brachytherapy for locally advanced cervical cancer from a U.S. academic center.

METHODS

A retrospective review was performed on patients treated with MRI-based brachytherapy for cervical cancer. EBRT was standardly 45 Gy in 25 fractions with weekly cisplatin. MRI was performed with the brachytherapy applicator in situ. Dose specification was most commonly 7 Gy for 4 fractions with optimization aim of D90 HR-CTV EQD2 of 85-95 Gyα/β=10 Gy in 2 implants each delivering 2 fractions.

RESULTS

Ninety-eight patients were included with median follow up of 24.5 months (IQR 11.9-39.8). Stage IIIA-IVB accounted for 31.6% of cases. Dosimetry results include median GTV D98 of 101.0 Gy (IQR 93.3-118.8) and HR-CTV D90 of 89 Gy (IQR 86.1-90.6). Median D2cc bladder, rectum, sigmoid, and bowel doses were 82.1 Gy (IQR 75.9-88.0), 65.9 Gy (IQR 59.6-71.2), 65.1 Gy (IQR 57.7-69.6), and 55 Gy (IQR 48.9-60.9). Chronic grade 3+ toxicities were seen in the bladder (8.2%), rectosigmoid (4.1%), and vagina (1.0%). Three-year LC, PFS, and OS were estimated to be 84%, 61.7%, and 76.1%, respectively.

CONCLUSION

MRI-based brachytherapy demonstrates excellent local control and acceptable rates of high-grade morbidity. These results are possible in our population with relatively large volume primary tumors and extensive local disease.

Investigating the Use of a Liquid Immunogenic Fiducial Eluter Biomaterial in Cervical Cancer Treatment

Globally, cervical cancer is the fourth leading cancer among women and is dominant in resource-poor settings in its occurrence and mortality. This study focuses on developing liquid immunogenic fiducial eluter (LIFE) Biomaterial with components that include biodegradable polymers, nanoparticles, and an immunoadjuvant. LIFE Biomaterial is designed to provide image guidance during radiotherapy similar to clinically used liquid fiducials while enhancing therapeutic efficacy for advanced cervical cancer. C57BL6 mice were used to grow subcutaneous tumors on bilateral flanks. The tumor on one flank was then treated using LIFE Biomaterial prepared with the immunoadjuvant anti-CD40, with/without radiotherapy at 6 Gy. Computed tomography (CT) and magnetic resonance (MR) imaging visibility were also evaluated in human cadavers. A pharmacodynamics study was also conducted to assess the safety of LIFE Biomaterial in healthy C57BL6 female mice. Results showed that LIFE Biomaterial could provide both CT and MR imaging contrast over time. Inhibition in tumor growth and prolonged significant survival (* p < 0.05) were consistently observed for groups treated with the combination of radiotherapy and LIFE Biomaterial, highlighting the potential for this strategy. Minimal toxicity was observed for healthy mice treated with LIFE Biomaterial with/without anti-CD40 in comparison to non-treated cohorts. The results demonstrate promise for the further development and clinical translation of this approach to enhance the survival and quality of life of patients with advanced cervical cancer.

Apparent diffusion coefficient values predict response to brachytherapy in bulky cervical cancer

BACKGROUND

Diffusion-weighted magnetic resonance imaging (DWI) provides a measurement of tumor cellularity. We evaluated the potential of apparent diffusion coefficient (ADC) values obtained from post-external beam radiation therapy (EBRT) DWI and prior to brachytherapy (BT) to predict for complete metabolic response (CMR) in bulky cervical cancer.

METHODS

Clinical and DWI (b value = 500 s/mm2) data were obtained from patients undergoing interstitial BT with high-risk clinical target volumes (HR-CTVs) > 30 cc. Volumes were contoured on co-registered T2 weighted images and 90th percentile ADC values were calculated. Patients were stratified by CMR (defined by PET-CT at three months post-BT). Relation of CMR with 90th percentile ADC values and other clinical factors (International Federation of Gynecology and Obstetrics (FIGO) stage, histology, tumor and HR-CTV size, pre-treatment hemoglobin, and age) was assessed both in univariate and multivariate logistic regression analyses. Youden's J statistic was used to identify a threshold value.

RESULTS

Among 45 patients, twenty-eight (62%) achieved a CMR. On univariate analysis for CMR, only 90th percentile ADC value was significant (p = 0.029) while other imaging and clinical factors were not. Borderline significant factors were HR-CTV size (p = 0.054) and number of chemotherapy cycles (p = 0.078). On multivariate analysis 90th percentile ADC (p < 0.0001) and HR-CTV size (p < 0.003) were highly significant. Patients with 90th percentile ADC values above 2.10 × 10- 3 mm2/s were 5.33 (95% CI, 1.35-24.4) times more likely to achieve CMR.

CONCLUSIONS

Clinical DWI may serve to risk-stratify patients undergoing interstitial BT for bulky cervical cancer.

Current Status and Future Directions of Image-Guided Adaptive Brachytherapy for Locally Advanced Cervical Cancer

PURPOSE

The standard of care for patients with locally advanced cervical cancer is definitive chemoradiation followed by a brachytherapy boost. This review describes the current status and future directions of image-guided adaptive brachytherapy for locally advanced cervical cancer.

METHODS

A systematic search of the PubMed and Clinicaltrials.gov databases was performed, focusing on studies published within the last 10 years. The search queried "cervical cancer [AND] image-guided brachytherapy [OR] magnetic resonance imaging (MRI) [OR] adaptive brachytherapy".

DISCUSSION

The retroEMBRACE and EMBRACE-I trials have established the use of MRI as the standard imaging modality for brachytherapy application and planning. Quantitative imaging and radiomics have the potential to improve outcomes, with three ongoing prospective studies examining the use of radiomics to further risk-stratify patients and personalize brachytherapy. Another active area of investigation includes utilizing the superior soft tissue contrast provided by MRI to increase the dose per fraction and decrease the number of fractions needed for brachytherapy, with several retrospective studies demonstrating the safety and feasibility of three-fraction courses. For developing countries with limited access to MRI, trans-rectal ultrasound (TRUS) appears to be an effective alternative, with several retrospective studies demonstrating improved target delineation with the use of TRUS in conjunction with CT guidance.

CONCLUSIONS

Further investigation is needed to continue improving outcomes for patients with locally advanced cervical cancer treated with image-guided brachytherapy.

Brachytherapy in gynecological malignancies at a tertiary care hospital: An analysis

Purpose

Brachytherapy plays a crucial role in the standard of care for locally advanced gynecological malignancies. In this report, we present the experience from a tertiary teaching hospital, which is a referral center for image-guided brachytherapy (IGBT) in the management of locally advanced gynecological malignancies.

Material and methods

This was a retrospective study of 130 patients referred to our hospital for IGBT after receiving initial external beam radiotherapy in their primary healthcare facilities, from January 2021 till January 2023. CT-based planning was done to delineate high-risk clinical target volume (HR-CTV). Dose of 6-7.5 Gy in 3-4 fractions was prescribed. Overall treatment time (OTT) was calculated, and patients were assessed for clinical response and toxicity after three months.

Results

All patients received IGBT using an intra-cavitary or interstitial technique. The D90 HR-CTV mean EQD2 dose was 28.34 ±2.78 Gy. The mean EQD2 dose to 2 cc of the bladder, rectum, and sigmoid was 18.31 ±5.19 Gy, 14.14 ±5.76 Gy, and 17.43 ±4.75 Gy, respectively. The median interval time between the last fraction of external beam radiation therapy (EBRT) and first evaluation in the hospital was 19 (range, 13-28) days (interquartile range [IQR]). The median time between the completion of chemoradiation and brachytherapy procedure was 25 (range, 19-33) days (IQR). The mean overall treatment time (OTT) was 63.5 ±14.7 days.

Conclusions

This study highlights the established advantages of image-guided interstitial brachytherapy and associated challenges. To optimize the overall treatment duration, it is imperative to prioritize and update the referral processes for brachytherapy centers.

Prediction of Patient Outcomes in Locally Advanced Cervical Carcinoma Following Chemoradiotherapy-Comparative Effectiveness of Magnetic Resonance Imaging and 2-Deoxy-2-[18F]fluoro-D-glucose Imaging

PURPOSE

To evaluate the utility and comparative effectiveness of three five-point qualitative scoring systems for assessing response on PET-CT and MRI imaging individually and in combination, following curative-intent chemoradiotherapy (CRT) in locally advanced cervical cancer (LACC). Their performance in the prediction of subsequent patient outcomes was also assessed; Methods: Ninety-seven patients with histologically confirmed LACC treated with CRT using standard institutional protocols at a single centre who underwent PET-CT and MRI at staging and post treatment were identified retrospectively from an institutional database. The post-CRT imaging studies were independently reviewed, and response assessed using five-point scoring tools for T2WI, DWI, and FDG PET-CT. Patient characteristics, staging, treatment, and follow-up details including progression-free survival (PFS) and overall survival (OS) outcomes were collected. To compare diagnostic performance metrics, a two-proportion z-test was employed. A Kaplan-Meier analysis (Mantel-Cox log-rank) was performed.

RESULTS

The T2WI (p < 0.00001, p < 0.00001) and DWI response scores (p < 0.00001, p = 0.0002) had higher specificity and accuracy than the PET-CT. The T2WI score had the highest positive predictive value (PPV), while the negative predictive value (NPV) was consistent across modalities. The combined MR scores maintained high NPV, PPV, specificity, and sensitivity, and the PET/MR consensus scores showed superior diagnostic accuracy and specificity compared to the PET-CT score alone (p = 0.02926, p = 0.0083). The Kaplan-Meier analysis revealed significant differences in the PFS based on the T2WI (p < 0.001), DWI (p < 0.001), combined MR (p = 0.003), and PET-CT/MR consensus scores (p < 0.001) and in the OS for the T2WI (p < 0.001), DWI (p < 0.001), and combined MR scores (p = 0.031) between responders and non-responders.

CONCLUSION

Post-CRT response assessment using qualitative MR scoring and/or consensus PET-CT and MRI scoring was a better predictor of outcome compared to PET-CT assessment alone. This requires validation in a larger prospective study but offers the potential to help stratify patient follow-up in the future.

Management and long-term clinical outcomes of patients with stage IVA cervical cancer with bladder involvement

OBJECTIVE

To describe the long-term outcomes of patients with stage IVA cervical cancer, a rare and deadly disease for which long-term toxicity data are scarce, to guide clinician counseling and survivorship support.

METHODS

In a retrospective review of a prospectively maintained database, we identified 76 patients with stage IVA cervical cancer with biopsy- or MRI-proven bladder mucosal involvement who received definitive radiotherapy (external beam radiotherapy [EBRT] alone or EBRT plus brachytherapy) with or without chemotherapy at our institution between 2000 and 2020. We used Kaplan-Meier modeling to estimate recurrence-free survival (RFS) and overall survival (OS) and used proportional hazard modeling to identify clinical variables associated with recurrence or survival. We performed actuarial competing risk modeling for severe late toxicity (grades 3 to 5, occurring >6 months of follow-up) and vesicovaginal fistulae (VVF), censoring for pelvic recurrence and death, and made comparisons between potential predictors using Gray's test and binary logistic regression.

RESULTS

The median follow-up time was 76 months (interquartile range 58-91). The median OS duration was 35 months (range, 18-not reached), and the 2- and 5-year OS rates were 53.6% and 40.9%, respectively. OS and RFS did not differ significantly between patients who received EBRT alone (N = 18) or EBRT plus brachytherapy (N = 49). Current smoking was a strong predictor of severe late toxicity, whose incidence was 14% at 2 years and 17% at 10 years. The VVF incidence was 24% at 2 years and 32% at 10 years.

CONCLUSION

Patients with stage IVA cervical cancer, even those who receive EBRT alone, can have long-term survival. These patients should be followed closely for late radiation-related toxicity.

Online Adaptive Magnetic Resonance-guided Radiation Therapy for Gynaecological Cancers: Preliminary Results of Feasibility and Outcome

AIMS

To present the preliminary results on the clinical utilisation of an online daily adaptive magnetic resonance-guided radiation therapy (MRgRT) for various gynaecological cancers.

MATERIALS AND METHODS

Twelve patients treated between September 2018 and June 2022 were included. Six patients (50%) were treated with pelvic radiation therapy followed by MRgRT boost as brachytherapy boost was ineligible or unavailable, three patients (25%) were treated with pelvic MRgRT followed by high dose rate brachytherapy, two patients (16.7%) were treated with only MRgRT, one patient (8.3%) was treated with linear accelerator-based radiation therapy followed by MRgRT boost for bulky iliac lymph nodes.

RESULTS

The median age was 56.5 years (range 31-86 years). Eight patients (66.7%) had a complete response, three patients (25%) had a partial response and one patient (8.3%) died due to acute renal failure. The mean follow-up time was 11.2 months (range 3.1-42.6 months). The estimated 1-year overall survival was 88.9%. The median treatment time was 47 days (range 10-87 days). During external beam radiation therapy, 10 (83.3%) patients had concomitant chemoradiotherapy. Pelvic external beam radiation therapy doses for all cohorts were 45-50.4 Gy with a fraction dose of 1.8 Gy. The median magnetic resonance-guided boost dose was 32 Gy (range 20-50 Gy) and fraction doses ranged between 4 and 10 Gy. Three patients were treated with intracavitary high dose rate brachytherapy (26-28 Gy in four to five fractions). None of the patients had grade >3 late genitourinary toxicities.

CONCLUSION

MRgRT is reliable and clinically feasible for treating patients with gynaecological cancers alone or in combination with brachytherapy with an acceptable toxicity and outcome. MRgRT boost could be an option when brachytherapy is not available or ineligible.

Clinical outcome after high dose rate intracavitary brachytherapy with traditional point 'A' dose prescription in locally advanced carcinoma of uterine cervix: dosimetric analysis from the perspective of computed tomography imaging-based 3-dimensional treatment planning

OBJECTIVE

To analyze tumour response and toxicity with respect to cumulative radiotherapy dose to target and organs at risk (OARs) with computed tomography (CT)-based image guided adaptive brachytherapy planning for locally advanced carcinoma cervix.

METHODS

Patients were treated with two-dimensional concurrent chemoradiotherapy to whole pelvis followed by intracavitary brachytherapy (ICBT) with dose prescription to point 'A'. CT image-based delineation of high-risk clinical target volume (HR-CTV), urinary bladder, rectum and sigmoid colon was done with generation of dose-volume histogram (DVH) data and optimization of doses to target and OARs. Follow up assessments were done for response of disease and toxicity with generation of data for statistical analysis.

RESULTS

One hundred thirty-six patients were enrolled in the study. Delineated volume of HR-CTV ranged from 20.9 to 37.1 mL, with median value of 30.2 mL. The equivalent dose in 2 Gy per fraction (EQD2) for point 'A' ranged from 71.31 to 79.75 Gy with median value of 75.1 Gy and EQD2 HR-CTV D90 ranged from 71.9 to 89.7 Gy with median value of 85.1 Gy. 69.2% of patients showed complete response and after median follow-up of 25 months, 50 patients remained disease free, of whom, 74.0% had received ≥85 Gy to HR-CTV D90 versus 26.0% receiving <85 Gy to HR-CTV D90.

CONCLUSION

s Amidst the unavailability of magnetic resonance imaging facilities in low middle income countries, incorporation of CT-image based treatment planning into routine practice for ICBT provides the scope to delineate volumes of target and OARs and to generate DVH data, which can prove to be a better surrogate for disease response and toxicity.

Outcomes and comparison of dosimetric parameters between intracavitary (Fletcher) and combined intracavitary/interstitial (Utrecht) brachytherapy in locally advanced cervical cancer

OBJECTIVE

To report outcomes of combined intracavitary/interstitial (IC/IS) image-guided brachytherapy (IGBT) in locally advanced cervical cancer, and to compare its dosimetric parameters with intracavitary-only (IC) brachytherapy in a first-in-country experience.

METHODS AND MATERIALS

Between January 2021 and September 2022, a total of 160 insertions were done in 40 patients with FIGO IB3-IVA cervical cancer undergoing IGBT using a hybrid (Utrecht) applicator. Corresponding treatment plans for IC brachytherapy were generated during treatment, and optimized. A preplanned comparison of dosimetric parameters, defined in GEC-ESTRO was conducted.

RESULTS

The clinical use of a hybrid IC/IS applicator was feasible in all insertions. An average of 14 needles were inserted in each patient over four fractions. Mean HR-CTV D90 and D98 was 86 (SD 1.9) Gy and 75.7 (SD 2.3) Gy using hybrid applicator, and 80 (SD 5.4) Gy and 69.8 (SD 5.2) Gy using IC applicator, with a mean dose gain of 6.0 (SD 5.0) Gy and 5.9 (SD 4.7) Gy (p <0.001), respectively. Likewise, mean D2cc for bladder and sigmoid were significantly lower in the hybrid technique. Mean contribution of brachytherapy to total HR-CTV D90 (in absolute EQD2 Gy) was 41.7 Gy using IC/IS applicator while 35.7 Gy for IC-only applicator (p = 0.027). Clinical response at 12 weeks showed an overall response rate (ORR) and complete response (CR) rates of 92.5% and 77.5%, respectively.

CONCLUSIONS

IGBT using a hybrid IC/IS applicator showed excellent tolerability and yielded favorable results, resulting in significant dosimetric improvement in terms of primary target dose, and sparing OARs.

High-Dose-Rate Three-Dimensional Image-Guided Adaptive Brachytherapy (3D IGABT) for Locally Advanced Cervical Cancer (LACC): A Narrative Review on Imaging Modality and Clinical Evidence

Background: Brachytherapy (BT) is a critical component of radiotherapy for locally advanced cervical cancer (LACC), and it has rapidly developed in recent decades. Since the advent of three-dimensional image-guided adaptive brachytherapy (3D-IGABT), magnetic resonance imaging (MRI) has emerged as the primary modality for image guidance. Meanwhile, other imaging modalities, such as computed tomography, 18F-fluorodeoxyglucose positron emission tomography, ultrasound, and their combinations have also been widely studied. Materials and methods: We reviewed studies on different imaging modalities utilized for target delineation and planning. Emerging techniques in IGABT like real-time image guidance and 3D printing were also included. We summarized research on their feasibility and concentrated on their clinical outcomes. Results: MRI-guided BT was the gold standard, and CT-guided BT was the most widely applied. Other modalities have shown feasibility and promising efficacy in dosimetry studies and preliminary outcomes. The longer-term clinical outcomes associated with these approaches require further elucidation. Conclusions: As 3D-IGABT was validated by promising clinical outcomes, the future of BT for LACC is expected to progress toward the refinement of more effective image-guided procedures. Moreover, achieving operational consensus and driving technological advancements to mitigate the inherent limitations associated with different imaging modes remain essential.

Clinical outcomes of single application multi-fractionated CT-guided interstitial high-dose-rate brachytherapy for locally advanced cervical cancer: A multi-institution initial experience

Purpose

The aim of the study was to evaluate the safety and clinical outcomes of single application multi-fractionated computed tomography (CT)-guided interstitial high-dose-rate brachytherapy given in four fractions in locally advanced cervical cancer.

Material and methods

Patients with locally advanced cervical cancer stage IIB-IVA treated definitively with external radiation ± weekly cisplatin, followed by single application multi-fractionated CT-guided interstitial high-dose-rate brachytherapy in four fractions were included. Dosimetry data, clinical response, and toxicity records were reviewed.

Results

Between January 2018 and December 2022, twenty-two patients were included. Clinical stage distribution was as follows: IIB - 13.6%, IIIB - 27.3%, IIIC - 22.7%, and IVA - 36.4%. Mean high-risk clinical target volume (HR-CTV) was 66.19 ±32.69 cm3, and HR-CTV D90 dose was 86.8 ±1.7 Gy. 2 cc doses to bladder, rectum, and sigmoid were 84.6 ±2.8 Gy, 71.5 ±2.4 Gy, and 65.6 ±4.0 Gy, respectively. Mean overall treatment time was 66 ±21 days. With a median follow-up of 11.5 months (range, 5-44 months), median survival and local control were not achieved. One-year local control rate, one-year progression-free survival, and one-year overall survival were 82%, 66%, and 78%, respectively. Univariate analysis showed overall treatment time to be the only variable associated with all oncologic outcomes. For acute toxicity, grade 3 toxicity in four patients and grade 4 toxicity of infection in one patient were observed. For late toxicity, grade 3 gastrointestinal toxicity was noted in two patients.

Conclusions

Initial results suggest that single application multi-fractionated CT-guided interstitial brachytherapy given in four fractions in locally advanced cervical cancer seems to be feasible and safe, but additional evidence is needed to generate more validated conclusions.

Combination of image-guided IMRT and IGBT in locally advanced carcinoma cervix: Prospective evaluation of toxicities and clinical outcomes from a tertiary cancer center in India

Purpose

We aimed to assess the toxicity profile and clinical outcome in patients with locally advanced cervical cancer (LACC) treated with a combination of image-guided intensity-modulated radiation therapy (IG-IMRT) and image-guided brachytherapy (IGBT).

Material and methods

25 LACC patients were recruited in this single-arm prospective study. Whole pelvis IG-IMRT was delivered (45 Gy with simultaneously integrated nodal boost of 55 Gy in 25 fractions), with concurrent weekly cisplatin (40 mg/m2). Patients received IGBT of 7 Gy each in 4 fractions to high-risk clinical target volume (HR-CTV). First fraction was done under MRI, and subsequent fractions were performed under CT guidance. Primary endpoint was acute toxicity, and secondary endpoints were 2-year loco-regional control and late toxicity.

Results

The median age was 52 years, and FIGO 2018 stage distribution was IIA2, IIB, IIIB, and IIIC1 in 12%, 40%, 20%, and 28% patients, respectively. All patients received concurrent chemotherapy with median number of 5 cycles (range, 4-5 cycles). Grade 1 and 2 diarrhea, and grade 1 cystitis was reported in 4 (16%), 3 (12%), and 2 (8%) patients, respectively. Grade 1 and 2 anemia, and grade 1 and 2 dermatitis were observed in 3 (12%) and 2 (8%), and 3 (12%) and 3 (12%) patients, respectively. No patient reported grade 3-4 acute toxicity. At median follow-up of 29.5 months (range, 25-37 months), late grade 1 bladder toxicity was observed in 1 (4%) patient. Loco-regional control at 1 and 2 years were 96% and 92%, respectively.

Conclusions

The combination of IG-IMRT and IGBT yielded excellent outcomes in terms of acute toxicity and loco-regional control.

Simultaneous Integrated Boost for Dose Escalation in Node-Positive Cervical Cancer: 5-Year Experience in a Single Institution

This study retrospectively evaluates clinical outcomes of dose escalation to involved nodes using volumetric modulated arc therapy (VMAT) with simultaneous integrated boost (SIB) for node-positive locally advanced cervical cancer (LACC) at a single institution. Consecutive patients with node-positive LACC (FIGO2018 IIIC1-IVA) who received definitive chemoradiotherapy by VMAT 45 Gy in 25 fractions with SIB to 55-57.5 Gy, followed by magnetic resonance image-guided adaptive brachytherapy (IGABT) between 2018 and 2022 were identified. A standardized strategy regarding nodal boost delivery and elective para-aortic (PAO) irradiation was employed. Primary endpoints were involved nodal control (INC) and regional nodal control (RNC). Secondary endpoints were pelvic control (PC), locoregional control (LRC), disease-free survival (DFS), overall survival (OS), failure pattern, and radiotherapy-related toxicities. A total of 234 involved nodes (182 pelvic and 52 PAO) in 54 patients, with a median of 3 involved nodes per patient (range 1-16), were analyzed. After a median follow-up of 19.6 months, excellent INC was achieved, with four (2%) boost-volume failures occurring in three patients. The 2-year actuarial RNC, PC, LRC, DFS, and OS were 93%, 87%, 87%, 78%, and 85%, respectively. Adenocarcinoma histology was associated with worse RNC (p = 0.02) and OS (p = 0.04), whereas the primary tumor maximum standardized uptake value (SUVmax) was associated with worse PC (p = 0.04) and LRC (p = 0.046) on univariate analysis. The incidence of grade ≥3 acute and late radiotherapy-related toxicity were 2% and 4%, respectively. Treatment of node-positive LACC with VMAT with SIB allows safe and effective dose escalation. The 5-year local experience demonstrated excellent treatment outcomes without additional toxicity.

The application of 3D brachytherapy in cervical stump cancer: A retrospective study

Purpose

Cervical stump cancer is a carcinoma that grows on the cervical stump after a sub-total hysterectomy. There have been no studies on the application of 3D brachytherapy in cervical stump cancer. In the present study, we aimed to compare the curative effects, toxicity, and dosimetry of 3D and 2D brachytherapy in cervical stump cancer.

Material and methods

Thirty-one patients admitted between 2012 and 2021, who were concurrently treated with intensity-modulated radiation therapy and brachytherapy for cervical stump cancer were divided into three groups according to the brachytherapy techniques: 2D brachytherapy, 3D image-guided brachytherapy (3D-IGBT), and 2D + 3D. For patients undergoing 2D brachytherapy and 3D-IGBT, data on survival, complications, and dose to target area or organs at risk (OARs) were collected and compared. Furthermore, dosimetry difference was investigated by reconstructing the 2D plan into a 3D plan.

Results

The median follow-up duration of all patients was 58 months. The overall 5-year progression-free survival, overall survival, and local control rates were 69.6%, 90.2%, and 78.2%, respectively. Late complications in the rectum, sigmoid colon, and bladder were milder in 3D brachytherapy than in 2D brachytherapy. Concerning the D90 value of clinical target volume (CTV) and D2cm3 value of OARs in EQD2, the 3D brachytherapy provided a lower dose to CTV (76.5 Gy vs. 95.9 Gy, on average) and OARs compared with 2D brachytherapy.

Conclusions

Despite lacking statistical significance, 3D brachytherapy showed better outcomes regarding late toxicity than 2D brachytherapy, owing to the lower dose coverage in the bladder, rectum, sigmoid colon, and small intestine.

Oncologic outcomes after MRI-assisted image-guided brachytherapy with hybrid interstitial and intra-cavitary applicators under moderate sedation for locally advanced cervix cancer

Purpose

To report outcomes of using image-guided hybrid intra-cavitary/interstitial applicators under moderate sedation for locally advanced cervical cancer patients in our institution.

Material and methods

A total of 69 fractions of brachytherapy with hybrid applicators were performed in 33 patients from January 2017 to April 2021. All patients underwent MRI pelvis 1 week pre-brachytherapy to determine suitability for interstitial brachytherapy and pre-plan needle placement. All insertion of applicators were performed under moderate sedation with midazolam and/or fentanyl. Fifty-eight (84.1%) fractions were planned with CT alone. Clinical outcomes, dose volume parameters, and toxicities were analyzed.

Results

The median follow-up was 28 months. A total of 320 needles (median, 5 needles per fraction) were implanted, with a median insertion depth of 3 cm (range, 1.5-4 cm). The median high-risk clinical target volume (HR-CTV) during initial brachytherapy was 34.5 cc (range, 17.8-74.7 cc). The median total EQD2 D2cc of the rectum, bladder, sigmoid, and small intestine colon was 71.8 Gy, 81.5 Gy, 69 Gy, and 58.3 Gy, respectively. The 2-year local control and overall survival were 80.7% and 77.7%, respectively. Larger volume HR-CTV was significantly associated with worse local control (HR = 1.08, p = 0.005) and overall survival (HR = 1.04, p = 0.015). None of the patients required in-patient admission or blood transfusion post-procedure. Late grade 3 gastrointestinal and genitourinary toxicities were observed in 4 patients (12.2%).

Conclusions

Hybrid applicators inserted under moderate sedation are feasible and safe. Image-guided interstitial brachytherapy with CT planning aided by MRI performed 1 week pre-brachytherapy is associated with favorable outcomes and modest toxicities.

Inter-observer variation of target volume delineation for CT-guided cervical cancer brachytherapy

Purpose

Delineation is a critical and challenging step in radiotherapy planning. Differences in delineation among observers are common, despite the presence of contouring guidelines. This study aimed to identify the inter-observer variability in the target volume delineation of computed tomography (CT)-guided brachytherapy for cervical cancer.

Material and methods

Four radiation oncologists (ROs) with different expertise levels delineated high-risk (HR) and intermediate-risk (IR) clinical target volume (CTV) according to GYN GEC-ESTRO recommendations, in a blinded manner on every CT set of ten locally advanced cervical cancer cases. The most experienced RO's contours were determined as the index and used for comparison. Dice similarity coefficient (DSC) and pairwise Hausdorff distance (HD) metrics were applied to compare the overlap and gross deviations of all contours.

Results

Median DSC for HR-CTV and IR-CTV were 0.73 and 0.76, respectively, and a good concordance was achieved for both in majority of contours. While there was no difference in DSC measurements for HR-CTV among the three ROs, RO-3 provided improved DSC values for IR-CTV (p = 0.01). Median HD95 was 5.02 mm and 6.83 mm, and median HDave was 1.69 mm and 2.21 mm for HR-CTV and IR-CTV, respectively. There was no significant difference among ROs in HR-CTV for HD95 or HDave; however, IR-CTV value was significantly improved according to RO-3 (p = 0.01). Case-by-case HD analysis showed no significant inter-observer variations, except for two cases.

Conclusions

The inter-observer agreement is generally high for target volumes in CT-guided brachytherapy for cervical cancer. The agreement is lower for IR-CTV than HR-CTV. The individual characteristics of each case and different expertise levels of the ROs may have caused the differences. Despite the good concordance for delineation, dosimetric consequences can still be clinically significant.

Retrospective analysis of local recurrence pattern by computed tomography image-guided intracavitary and interstitial brachytherapy for locally advanced cervical cancer in a single Japanese institution

PURPOSE

The purpose of this study was to investigate the treatment results with focus on local control (LC) by computed tomography (CT)-guided intracavity brachytherapy and interstitial brachytherapy (ICBT/ISBT) for locally advanced cervical cancer (LACC).

METHODS AND MATERIALS

Patients with LACC undergoing ICBT/ISBT at least once in our institution between January 2017 and June 2019 were analyzed retrospectively. The primary endpoint was local control (LC), and the secondary endpoints were progression-free survival (PFS), overall survival (OS), and late toxicities. Differences between patient subgroups for prognostic factors in LC, PFS, and OS were analyzed using the log-rank test. The recurrence patterns of LC were also investigated.

RESULTS

Forty-four patients were included in the present study. The median high-risk clinical target volume (HR-CTV) at the initial brachytherapy was 48.2 cc. The median total dose of HR-CTV D90 (EQD2) was 70.7 Gy. The median followup period was 39.4 months. The 3-year LC, PFS and OS rates in all patients were 88.2%, 56.6%, and 65.4% (95% CI 50.3-78.0%), respectively. Corpus invasion and large HR-CTV (70 cc or more) were significant prognostic factors in LC, PFS, and OS. Marginal recurrences at the fundus of the uterus were detected in 3 of 5 patients in whom local recurrence was observed. Late toxicities of Grade 3 or higher were detected in 3 patients (6.8%).

CONCLUSIONS

Favorable LC was achieved by performing CT-guided ICBT/ISBT for LACC. The brachytherapy strategy for patients with corpus invasion or large HR-CTV may need to be reconsidered.

Application of three-dimensional multi-imaging combination in brachytherapy of cervical cancer

BACKGROUND

Three-dimensional (3D) imaging has an important role in brachytherapy and the treatment of cervical cancer. The main imaging methods used in the cervical cancer brachytherapy include magnetic resonance imaging (MRI), computer tomography (CT), ultrasound (US), and positron emission tomography (PET). However, single-imaging methods have certain limitations compared to multi-imaging. The application of multi-imaging can make up for the shortcomings and provide a more suitable imaging selection for brachytherapy.

PURPOSE

This review details the situation and scope of existing multi-imaging combination methods in cervical cancer brachytherapy and provides a reference for medical institutions.

MATERIALS AND METHODS

Searched the literature related to application of three-dimensional multi-imaging combination in brachytherapy of cervical cancer in PubMed/Medline and Web of Science electronic databases. Summarized the existing combined imaging methods and the application of each method in cervical cancer brachytherapy.

CONCLUSION

The current imaging combination methods mainly include MRI/CT, US/CT, MRI/US, and MRI/PET. The combination of two imaging tools can be used for applicator implantation guidance, applicator reconstruction, target and organs at risk (OAR) contouring, dose optimization, prognosis evaluation, etc., which provides a more suitable imaging choice for brachytherapy.

Implementing cone-beam computed tomography-guided online adaptive radiotherapy in cervical cancer

Background and purpose

Adaptive radiotherapy (ART) in locally advanced cervical cancer (LACC) has shown promising outcomes. This study investigated the feasibility of cone-beam computed tomography (CBCT)-guided online ART (oART) for the treatment of LACC.

Material and methods

The quality of the automated radiotherapy treatment plans and artificial intelligence (AI)-driven contour delineation for LACC on a novel CBCT-guided oART system were assessed. Dosimetric analysis of 200 simulated oART sessions were compared with standard treatment. Feasibility of oART was assessed from the delivery of 132 oART fractions for the first five clinical LACC patients. The simulated and live oART sessions compared a fixed planning target volume (PTV) margin of 1.5 cm around the uterus-cervix clinical target volume (CTV) with an internal target volume-based approach. Workflow timing measurements were recorded.

Results

The automatically-generated 12-field intensity-modulated radiotherapy plans were comparable to manually generated plans. The AI-driven organ-at-risk (OAR) contouring was acceptable requiring, on average, 12.3 min to edit, with the bowel performing least well and rated as unacceptable in 16 % of cases. The treated patients demonstrated a mean PTV D98% (+/-SD) of 96.7 (+/- 0.2)% for the adapted plans and 94.9 (+/- 3.7)% for the non-adapted scheduled plans (p<10^-5). The D2cc (+/-SD) for the bowel, bladder and rectum were reduced by 0.07 (+/- 0.03)Gy, 0.04 (+/-0.05)Gy and 0.04 (+/-0.03)Gy per fraction respectively with the adapted plan (p <10^-5). In the live.setting, the mean oART session (+/-SD) from CBCT acquisition to beam-on was 29 +/- 5 (range 21-44) minutes.

Conclusion

CBCT-guided oART was shown to be feasible with dosimetric benefits for patients with LACC. Further work to analyse potential reductions in PTV margins is ongoing.

Dose prediction of organs at risk in patients with cervical cancer receiving brachytherapy using needle insertion based on a neural network method

OBJECTIVE

A neural network method was employed to establish a dose prediction model for organs at risk (OAR) in patients with cervical cancer receiving brachytherapy using needle insertion.

METHODS

A total of 218 CT-based needle-insertion brachytherapy fraction plans for loco-regionally advanced cervical cancer treatment were analyzed in 59 patients. The sub-organ of OAR was automatically generated by self-written MATLAB, and the volume of the sub-organ was read. Correlations between D2cm³ of each OAR and volume of each sub-organ-as well as high-risk clinical target volume for bladder, rectum, and sigmoid colon-were analyzed. We then established a neural network predictive model of D2cm³ of OAR using the matrix laboratory neural net. Of these plans, 70% were selected as the training set, 15% as the validation set, and 15% as the test set. The regression R value and mean squared error were subsequently used to evaluate the predictive model.

RESULTS

The D2cm³/D90 of each OAR was related to volume of each respective sub-organ. The R values for bladder, rectum, and sigmoid colon in the training set for the predictive model were 0.80513, 0.93421, and 0.95978, respectively. The ∆D2cm³/D90 for bladder, rectum, and sigmoid colon in all sets was 0.052 ± 0.044, 0.040 ± 0.032, and 0.041 ± 0.037, respectively. The MSE for bladder, rectum, and sigmoid colon in the training set for the predictive model was 4.779 × 10^-3, 1.967 × 10^-3 and 1.574 × 10^-3, respectively.

CONCLUSION

The neural network method based on a dose-prediction model of OAR in brachytherapy using needle insertion was simple and reliable. In addition, it only addressed volumes of sub-organs to predict the dose of OAR, which we believe is worthy of further promotion and application.

Clinical transfer of AGuIX®-based radiation treatments for locally advanced cervical cancer: MR quantification and in vitro insights in the NANOCOL clinical trial framework

Clinical trials incorporating metallic nanoparticles (NPs) have recently begun. Radiotherapy planning does not take into account NPs concentrations observed in the patients' target volumes. In the framework of the NANOCOL clinical trial including patients treated for locally advanced cervical cancers, this study proposes a complete method to evaluate the radiation-induced biological effects of NPs. For this, calibration phantom was developed and MRI sequences with variable flip angles were acquired. This process allowed the quantification of NPs in the tumor of 4 patients, which was compared to the results of mass spectrometry obtained from 3 patient biopsies. The concentration of the NPs was reproduced in 3D cell models. Based on clonogenic assays, the radio-enhancement effects were quantified for radiotherapy and brachytherapy, and the impact in terms of local control was evaluated. T₁ signal change in GTVs revealed NPs accumulation ~12.4 μmol/L, in agreement with mass spectrometry. Radio-enhancement effects of about 15 % at 2 Gy were found for both modalities, with a positive impact on local tumor control. Even if further follow-up of patients in this and subsequent clinical trials will be necessary to assess the reliability of this proof of concept, this study opens the way to the integration of a dose modulation factor to better take into account the impact of NPs in radiotherapy treatment.

The Effect of Contemporary Brachytherapy Practices on Prognosis in Women with Locally Advanced Cervical Cancer

(1) Background: Over the past two decades use of new imaging modalities and the adaptation of applicators have allowed for advances in volumetric (3D) imaging-based brachytherapy practices for patients with locally advanced cervical cancer. The aim of this study was to compare the oncological outcome and toxicity for three consecutively introduced brachytherapy practices in a large single-center cohort; (2) Methods: Patients treated for cervical cancer with primary radiotherapy and curative intent were consecutively included in this retrospective, single-center cohort study from 2006 to 2019. This cohort was divided into three groups (CT, MRI, and MRI+needles) based on the timing of the introduction of a novel brachytherapy practice; 3D brachytherapy planning using CT- and MRI-guided adaptive brachytherapy and the use of parametrial interstitial needles, respectively. Actuarial estimates were compared between groups. Multivariable Cox regression analyses were performed to correct for other risk factors. Crude rates of severe (≥grade 3) late toxicity were reported; (3) Results: A total of 397 patients were included in this cohort. At a median follow-up of 40 months (interquartile range (IQR) 22-62), actuarial 3-year local control, pelvic control, disease-free survival, and overall survival for the entire cohort were 91% (95% (Confidence Interval (CI)) 88-94), 88% (95% CI 84-91), 69% (95% CI 64-74), and 75% (95% CI 70-79), respectively). Local control, disease-free survival, and overall survival were significantly improved in the MRI+needles group compared to the CT group (p = 0.040, p = 0.004, and p < 0.001, respectively). Independent risk factors for overall survival were treatment in either the CT or MRI group (vs. MRI+needles), older age at diagnosis, adeno (squamous) carcinoma, FIGO stage III/IV, and lymph node metastases. The crude rate of severe late toxicity was 27% in the CT, 26% in the MRI, and 20% in the MRI+needles group; (4) Conclusions: Prognosis in women with locally advanced cervical cancer treated with state-of-the-art MRI-guided adaptive brachytherapy combined with parametrial interstitial needles compares favorably to patients treated with more traditional CT only based brachytherapy.

Safety and efficacy of single insertion accelerated MR-image guided brachytherapy following chemo-radiation in locally advanced cervix cancer: modifying our EMBRACE during the COVID pandemic

BACKGROUND

Utero-vaginal brachytherapy (BT) is an irreplaceable care component for the curative treatment of locally advanced cervix cancer (LACC). Magnetic Resonance Imaging (MRI)-image guided adaptive BT (IGABT) using the GYN-GEC-ESTRO EMBRACE guidelines is the international care standard. Usually following chemo-radiation therapy (CRT), IGABT has high proven utility in LACC but requires significant health system resources. Timely access was disrupted by the COVID-19 pandemic which challenged us to re-design our established IGABT care pathway.

METHODS

From April 2020 consecutive patients with LACC were enrolled after CRT in a single arm exploratory non-inferiority study of a modified IGABT (mIGABT) protocol. This delivered an iso-effective IGABT dose (39.3 Gy: EQD2: α/β10Gy concept) over a 24-h period during a single overnight hospitalisation.

RESULTS

Fourteen LACC patients received mIGABT from April 2020 to March 2022. Median age was 62.5 years (37-82 years). LACC histology was primary squamous (9/14) or adeno-carcinoma (5/14). International Federation of Gynaecology and Obstetrics (FIGO) 2018 stages ranged from IB1/2 (N = 3), IIA1/IIB (5), IIIB (2), IIIC1/2 (4) with mean ± standard deviation (SD) gross tumour volume-at-diagnosis (GTV_D) of 37.7 cc ± 71.6 cc. All patients achieved complete metabolic, clinical, and cytologic cancer response with CRT and IGABT. High-risk HPV was cleared by 6-months. Complete MRI-defined cancer response before mIGABT (GTV_Fx1) was seen in 77% of cases (10/13). Only two women developed metastatic disease and one died at 12-months; 13 patients were alive without cancer at mean 20.3 ± 7.2 months follow-up. Actuarial 2-year overall survival was 93%. Compared with our pre-COVID IGABT program, overall mIGABT cost-saving in this cohort was USD 22,866. Prescribed dose covered at least 90% (D90) of the entire cervix and any residual cancer at time of BT (HRCTV_D90: high-risk clinical target volume) with 3-fractions of 8.5 Gy delivered over 24-h (22.8 ± 1.7 h). Total treatment time including CRT was 38 days. The mIGABT schedule was well tolerated and the entire cohort met EMBRACE recommended (EQD2: α/β10Gy) combined HRCTV_D90 coverage of 87.5 ± 3.7 Gy. Similarly, organ-at-risk (OAR) median: interquartile range D2cc constraints (EQD2: α/β3Gy) were EMBRACE compliant: bladder (65.9 Gy: 58.4-72.5 Gy), rectum (59.1 Gy: 55.7-61.8 Gy), and sigmoid colon (54.6 Gy: 50.3-58.9 Gy). ICRU recto-vaginal point dose was significantly higher (75.7 Gy) in our only case of severe (G4) pelvic toxicity.

CONCLUSIONS

This study demonstrated the utility of mIGABT and VMAT CRT in a small cohort with LACC. Loco-regional control was achieved in all cases with minimal emergent toxicity. Single insertion mIGABT was logistically efficient, cost-saving, and patient-centric during the COVID-19 pandemic.

Comparing dosimetry of locally advanced cervical cancer patients treated with 3 versus 4 fractions of MRI-guided brachytherapy

PURPOSE

To demonstrate the feasibility of treating cervical cancer patients with MRI-guided brachytherapy (MRgBT) using 24 Gy in 3 fractions (F) versus a standard, more resource-intensive regimen of 28 Gy in 4F, and its ability to meet EMBRACE II planning aims.

METHODS AND MATERIALS

A retrospective review of 224 patients with FIGO Stage IB-IVA cervical cancer treated with 28 Gy/4F (n = 91) and 24 Gy/3F (n = 133) MRgBT between 2016-2021 was conducted. Multivariable linear regression models were fitted to compare dosimetric parameters between the two groups, adjusting for CTV_HR and T stage.

RESULTS

Most patients had squamous cell carcinoma, T2b disease, and were treated with intracavitary applicator plus interstitial needles (96%). The 28 Gy/4F group had higher CTV_HR (median 28 vs. 26 cm³, p = 0.04), CTV_IR D_98% (mean 65.5 vs. 64.5 Gy, p = 0.03), rectum D_2cm3 (mean 61.7 vs. 59.2 Gy, p = 0.04) and bladder D_2cm3 (81.3 vs. 77.9 Gy, p = 0.03). There were no significant differences in the proportion of patients meeting the EMBRACE II OAR dose constraints and planning aims, except fewer patients treated with 28 Gy/4F met rectum D_2cm3 < 65 Gy (73 vs. 85%, p = 0.027) and ICRU rectovaginal point < 65 Gy (65 vs. 84%, p = 0.005).

CONCLUSIONS

Cervical cancer patients treated with 24 Gy/3F MRgBT had comparable target doses and lower OAR doses compared to those treated with 28 Gy/4F. A less-resource intense fractionation schedule of 24 Gy/3F is an alternative to 28 Gy/4F in cervix MRgBT.

Characteristics of preplan-based three-dimensional individual template-guided brachytherapy compared to freehand implantation

Image-guided adaptive intracavitary/interstitial brachytherapy (IC/IS IGABT) has exhibited superior dosimetry advantage and local control for locally advanced cervical cancer (LACC). Our group designed a type of cylindrical three-dimensional (3D) printed vaginal template combining an intracavitary applicator with straight and oblique interstitial needles according to the preplan on computed tomography images. This work aimed to research the consistency of the preplan with the treatment plan at every fraction to verify the practical guiding significance of the preplan. We also investigated the difference between 3D-printed template-guided implantation compared with freehand implantation for LACC. Twenty-six patients were treated with 3D-printed individual templates (3D template group), and 20 patients were treated by using freehand insertion (freehand group). Patients in the 3D template group would take a preplan one week before treatment to design and print the individual template, while the freehand group did not. All patients accepted volumetric rotational intensity-modulated radiotherapy at a dose of 49.4 Gy in 26 fractions and subsequent brachytherapy at a dose of 26 Gy in four fractions. All analyses were performed by utilizing SPSS 26. The insertion depth was decreased in fractions 1 and 4 compared with the preplan. None of the dose volume histogram parameters of fractions 1-3, nor the D_2cc of bladder and bowel at fraction 4 were barely changed compared with the preplan. The D₉₀ and D₉₈ of the high-risk clinical target volume in the 3D template group were statistically higher than those in the freehand group (p < 0.01). The D_2cc of the rectum, bladder, bowel, and sigmoid in the 3D template group were all lower than those in the freehand group (p < 0.01). The preplan in this research is consistent with treatment plans, which is important to ensure the feasibility of applying a 3D-printed template in brachytherapy. The 3D-printed individual guidance template was an effective method in brachytherapy for locally advanced cervical cancer.

Visual analysis of image-guided radiation therapy based on bibliometrics: A review

Radiation therapy plays an important role in tumor treatment. The development of image-guided radiation therapy (IGRT) technology provides a strong guarantee for precise radiation therapy of tumors. However, bibliometric studies on IGRT research have rarely been reported. This study uses literature collected from the Web of Science during 1987 to 2021 as a sample and uses the bibliometric method to reveal the current research status, hotspots, and development trends in IGRT. Based on 6407 papers published from the Web of Science during 1987 to 2021, we utilized Microsoft Excel 2007 and cite space software to perform statistical analysis and visualization of IGRT. A total of 6407 articles were included, this area of IGRT has gone through 4 stages: budding period, growth period, outbreak period, and stationary period. The research category is mainly distributed in Radiology Nuclear Medicine Medical Imaging, which intersects with the research categories of Materials, Physics, and Mathematics. Yin FF, Tanderup K, and Sonke JJ are highly productive scholars who are active in IGRT research, while Jaffray DA, van Herk M and Guckenberger M are authors with high impact in this field. The team of scholars has close cooperation within the team and weak cooperation among teams. The League of European Research Universities, University of Texas System, University of Toronto, and Princess Margaret Cancer are the main research institutions in this field. The United States has the most research literature, followed by China and Germany. Six thousand four hundred seven articles are distributed in 712 journals, and the top 3 journals are Med Phys, Int J Radiat Oncol, and Radiather Oncol. Precise registration, intelligence, magnetic resonance guidance, and deep learning are current research hotspots. These results demonstrate that the research in this field is relatively mature and fruitful in the past 35 years, providing a solid theoretical basis and practical experience for precision radiotherapy.

Overall Severe Morbidity After Chemo-Radiation Therapy and Magnetic Resonance Imaging-Guided Adaptive Brachytherapy in Locally Advanced Cervical Cancer: Results From the EMBRACE-I Study

PURPOSE

To evaluate overall severe late morbidity (grade ≥3) in patients with locally advanced cervical cancer treated with chemo-radiation therapy and magnetic resonance image guided adaptive brachytherapy within the prospective EMBRACE-I study, and to compare the results with published literature after standard radiograph based brachytherapy (BT).

METHODS AND MATERIALS

From 2008 to 2015 the EMBRACE-I study enrolled 1416 patients. Morbidity was assessed (Common Terminology Criteria for Adverse Events version 3.0) every 3 months the 1st year, every 6 months the second and third year, and yearly thereafter and 1251 patients had available follow-up on late morbidity. Morbidity events (grade 3-5) were summarized as the maximum grade during follow-up (crude incidence rates) and actuarial estimates at 3 and 5 years. To compare with the published literature on standard radiograph based BT, Common Terminology Criteria for Adverse Events scores from the EMBRACE-I study were retrospectively converted into a corresponding score in the Radiation Therapy Oncology Group and European Organization for Research and Treatment of Cancer system.

RESULTS

In total, 534 severe events occurred in 270 patients; 429 events were grade 3 and 105 were grade 4 events. Actuarial estimates for grade ≥3 gastrointestinal (GI), genitourinary (GU), vaginal and fistula events at 5 years were 8.5% (95% confidence interval [CI], 6.9%-10.6%), 6.8% (95% CI, 5.4%-8.6%), 5.7% (95% CI, 4.3%-7.6%), and 3.2% (95% CI, 2.2%-4.5%), respectively. The 5-year actuarial estimate for organ-related events (GI, GU, vaginal, or fistula) was 18.4% (95% CI, 16.0%-21.2%). The 5-year actuarial estimate when aggregating all G≥3 endpoints (GI, GU, vaginal, fistulas, and non-GI/GU/vaginal) was 26.6% (95% CI, 23.8%-29.6%). Thirteen patients had a treatment-related death, 8 of which were associated with GI morbidity.

CONCLUSIONS

This report assesses severe morbidity from the largest prospective study on chemo-radiation therapy and image guided adaptive brachytherapy for locally advanced cervical cancer to date. Severe late morbidity was limited per endpoint and organ category, but considerable when aggregated across organs and all endpoints. The late morbidity results in the EMBRACE-I study compare favorably with published literature on standard radiograph based BT for GI morbidity, vaginal morbidity, and fistulas.

Risk Factors for Local Failure Following Chemoradiation and Magnetic Resonance Image-Guided Brachytherapy in Locally Advanced Cervical Cancer: Results From the EMBRACE-I Study

PURPOSE

To report clinical and treatment characteristics, remission and failure patterns, and risk factors for local failure (LF) from the EMBRACE-I study.

MATERIALS AND METHODS

EMBRACE-I was a prospective, observational, multicenter cohort study on magnetic resonance imaging-based image-guided adaptive brachytherapy (MR-IGABT) in locally advanced cervical cancer. Treatment consisted of external beam radiotherapy, concurrent chemotherapy, and MR-IGABT. LF was defined as progressive or recurrent disease in the cervix, uterus, parametria, pelvic wall, or vagina. Competing risk analysis was used to estimate local tumor control (LC) and Cox proportional regression models for multivariable analysis and dose-response analysis.

RESULTS

One thousand three hundred eighteen patients with a median follow-up of 52 months were available for this analysis. Eighty-one patients had persistent disease 3 months after end of treatment. Of those, 60 patients achieved LC at 6-9 months without further treatment, whereas 21 patients had progressive disease. In addition, 77 patients developed a local recurrence after complete remission comprising a total number of 98 LFs. LFs were located inside the MR-IGABT target volumes in 90% of patients with LF. In multivariable analysis, histology, minimal dose to 90% of high-risk clinical target volume (CTV_HR), maximum tumor dimension, CTV_HR > 45 cm³, overall treatment time, tumor necrosis on magnetic resonance imaging at diagnosis, uterine corpus infiltration at diagnosis and at MR-IGABT, and mesorectal infiltration at MR-IGABT had significant impact on LF. Dose-response analysis showed that a minimal dose to 90% of 85 Gy to the CTV_HR led to 95% (95% CI, 94 to 97) LC 3 years postintervention for squamous cell in comparison to 86% (95% CI, 81 to 90) for adeno/adenosquamous carcinoma histology.

CONCLUSION

The present study demonstrates the safety and validity of the GYN GEC-ESTRO/ICRU-89 target concept and provides large-scale evidence for dose prescription and new risk factors for LF in MR-IGABT in locally advanced cervical cancer.

Use of 3D planning of HDR brachytherapy in patients with cervical cancer

Background. Combined radiation therapy is the «gold standard» for the treatment of stages IIB-IVA of cervical cancer (cervical cancer). Given the data of statistical indicators of cervical cancer, the study of new approaches to treatment and implementation in clinical practice of modern technologies of radiation therapy of widespread cervical cancer is an extremely important area. Purpose – evaluate the benefits of using CT topometric preparation in planning brachytherapy for cervical cancer. Materials and Methods. 3D planning of brachytherapy of 24 patients with locally advanced cervical cancer (FIGO IIIB stage), who underwent a radical program of combined radiation therapy (remote radiation therapy with chemical modification with cisplatin followed by HDR-brachytherapy (High dose rate brachytherapy)). Results. The paper presents the results of the analysis of differences in brachytherapy planning according to orthogonal images and CT images. The analysis of the influence of the constitutional features of patients revealed that there are differences in the topographic anatomy of the pelvis depending on the surface area of the body. In patients with a body surface area of up to 1,65 m2 , a more intimate fit of the intestine to the target volume of irradiation was noted. No similar planning difficulties were found in patients with a body surface area above 1,65 m2 . Conclusions. The use of 3D images in the planning of intracavitary irradiation in patients with cervical cancer provides precision brachytherapy by simultaneously visualizing the irradiated volumes and spatial relationships of the anatomical structures of the pelvis, the introduced endostats and the corresponding volumetric dose distributions.

Prognostic Impact of Caspase-8, CDK9 and Phospho-CDK9 (Thr 186) Expression in Patients with Uterine Cervical Cancer Treated with Definitive Chemoradiation and Brachytherapy

Introduction: After primary platinum-based chemoradiation of locally advanced uterine cervical cancer, a substantial proportion of women present with persistent, recurrent or metastatic disease, indicating an unmet need for biomarker development. Methods: We evaluated the clinical records of 69 cervical cancer patients (Federation of Gynecology and Obstetrics, FIGO Stage > IB3) who were subjected to definitive CRT. Immunohistochemical scoring of caspase-8, cyclin dependent kinase 9 (CDK9) and phosphorylated (phospho-)CDK9 (threonine (Thr) 186) was performed on pretreatment samples and correlated with the histopathological and clinical endpoints, including relapse-free survival (RFS), distant metastasis-free survival (DMFS), cancer-specific survival (CSS) and overall survival (OS). Results: Lower levels of caspase-8 were more prevalent in patients with a higher T-stage (p = 0.002) and a higher FIGO stage (p = 0.003), and were significantly correlated with CDK9 expression (p = 0.018) and inversely with pCDK9 detection (p = 0.014). Increased caspase-8 levels corresponded to improved RFS (p = 0.005), DMFS (p = 0.038) and CSS (p = 0.017) in the univariate analyses. Low CDK9 expression was associated with worse RFS (p = 0.008), CSS (p = 0.015) and OS (p = 0.007), but not DMFS (p = 0.083), and remained a significant prognosticator for RFS (p = 0.003) and CSS (p = 0.009) in the multivariate analyses. Furthermore, low pCDK9 staining was significantly associated with superior RFS (p = 0.004) and DMFS (p = 0.001), and increased CSS (p = 0.022), and remained significant for these endpoints in the multivariate analyses. Conclusion: Increased caspase-8 and CDK9 levels correlate with improved disease-related outcomes in cervical cancer patients treated with CRT, whereas elevated pCDK9 levels predict worse survival in this patient population.