Ring Versus Ovoids and Intracavitary Versus Intracavitary-Interstitial Applicators in Cervical Cancer Brachytherapy: Results From the EMBRACE I Study

Three-dimensional trans-rectal and trans-abdominal ultrasound image fusion for the guidance of gynecologic brachytherapy procedures: a proof of concept study

High dose-rate brachytherapy is a treatment technique for gynecologic cancers where intracavitary applicators are placed within the patient's pelvic cavity. To ensure accurate radiation delivery, localization of the applicator at the time of insertion is vital. This study proposes a novel method for acquiring, registering, and fusing three-dimensional (3D) trans-abdominal and 3D trans-rectal ultrasound (US) images for visualization of the pelvic anatomy and applicators during gynecologic brachytherapy. The workflow was validated using custom multi-modal pelvic phantoms and demonstrated during two patient procedures. Experiments were performed for three types of intracavitary applicators: ring-and-tandem, ring-and-tandem with interstitial needles, and tandem-and-ovoids. Fused 3D US images were registered to magnetic resonance (MR) and computed tomography (CT) images for validation. The target registration error (TRE) and fiducial localization error (FLE) were calculated to quantify the accuracy of our fusion technique. For both phantom and patient images, TRE and FLE across all modality registrations (3D US versus MR or CT) resulted in mean ± standard deviation of 4.01 ± 1.01 mm and 0.43 ± 0.24 mm, respectively. This work indicates proof of concept for conducting further clinical studies leveraging 3D US imaging as an accurate, accessible alternative to advanced modalities for localizing brachytherapy applicators.

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.

Interstitial needles versus intracavitary applicators only for locally advanced cervical cancer: results from real-life dosimetric comparisons

Background and purpose

Image-guided adapted brachytherapy (IGABT) is superior to other radiotherapy techniques in the treatment of locally advanced cervical cancer (LACC). We aimed to investigate the benefit of interstitial needles (IN) for a combined intracavitary/interstitial (IC/IS) approach using IGABT over the intracavitary approach (IC) alone in patients with LACC after concomitant external beam radiotherapy (EBRT) and chemotherapy.

Materials and methods

We included consecutive patients with LACC who were treated with IC/IS IGABT after radiochemotherapy (RCT) in our retrospective, observational study. Dosimetric gain and sparing of organs at risk (OAR) were investigated by comparing the IC/IS IGABT plan with a simulated plan without needle use (IC IGABT plan) and the impact of other clinical factors on the benefit of IC/IS IGABT.

Results

Ninety-nine patients were analyzed, with a mean EBRT dose of 45.5 ± 1.7 Gy; 97 patients received concurrent chemotherapy. A significant increase in median D90% High Risk Clinical target volume (HR-CTV) was found for IC/IS (82.8 Gy) vs IC (76.2 Gy) (p < 10-4). A significant decrease of the delivered dose for all OAR was found for IC/IS vs IC for median D2cc to the bladder (77.2 Gy), rectum (68 Gy), sigmoid (53.2 Gy), and small bowel (47 Gy) (all p < 10-4).

Conclusion

HR-CTV coverage was higher with IC/IS IGABT than with IC IGABT, with lower doses to the OAR in patients managed for LACC after RCT. Interstitial brachytherapy in the management of LACC after radiotherapy provides better coverage of the target volumes, this could contribute to better local control and improved survival of patients.

Patterns of practice survey for cervical cancer brachytherapy in Morocco

PURPOSE

This study surveyed radiation oncologists in Morocco to explore current practices and perspectives on brachytherapy for cervix cancer.

METHODS AND MATERIALS

A 37-question survey was conducted in April 2023 among 165 Moroccan radiation oncologists using Google Forms.

RESULTS

Of the 93 respondents, 39% treated over 20 patients in 2022 using 3D image-guided brachytherapy (BT) through the HDR technique; 2D techniques were not reported in the last five years. Intracavitary BT is uniformly applied with a tandem and ovoid applicator. Only 14% utilized interstitial needles for hybrid BT. Iridium-192 was the primary radioactive source (63%), followed by cobalt (37%). Ultrasound-guided 47% of applicator insertions. All used CT scans for planning, but only 6% used MRI fusion due to limited availability. Guidelines for target volume and dose prescription were mostly based on GEC-ESTRO recommendations (74%), followed by Manchester Point A (30.4%) and ABS (11%). Over 90% delineated CTV-HR and CTV-IR; 30% delineated GTV. All marked the bladder and rectum, while 52% marked the sigmoid, 5% the small bowel, and 3% the recto-vaginal point. For dosimetry, 12% used ICRU 89 points, 54% used dose-volume histograms (DVH), and 36% used both. Most reported EQD2cc for OARs for the rectum and bladder, with nine still using ICRU point doses. The most common fractionation schema was 7 Gy in four fractions (60%) and 7 Gy in three fractions (55%).

CONCLUSIONS

Brachytherapy remains essential for treating cervical cancer in Morocco. Key areas for improvement include MRI fusion-guided brachytherapy, access to advanced applicators, expanding interstitial techniques, and professional training and national referential.

Developing Next-Generation 3-Dimensional Printing for Cervical Cancer Hybrid Brachytherapy: A Guided Interstitial Technique Enabling Improved Flexibility, Dosimetry, and Efficiency

PURPOSE

We developed a 3-dimensionally (3D) printed tandem anchored radially guiding interstitial template (TARGIT) to increase the simplicity of intracavitary/interstitial technique for tandem-and-ovoid (T&O) procedures in cervical cancer brachytherapy. This study compared dosimetry and procedure logistics between T&O implants using the original TARGIT versus the next-generation TARGIT-Flexible-eXtended (TARGIT-FX) 3D-printed template designed for practice-changing ease-of-use with further simplified needle insertion and increased flexibility in needle placement.

METHODS AND MATERIALS

This single-institution retrospective cohort study included patients undergoing T&O brachytherapy as part of definitive cervical cancer treatment. Procedures used the original TARGIT from November 2019 through February 2022 and the TARGIT-FX from March 2022 through November 2022. The FX design features full extension to the vaginal introitus with 9 needle channels and allows for needle additions or depth adjustments intraprocedure and after computed tomography/magnetic resonance imaging.

RESULTS

A total of 148 implants were performed, 68 (46%) with TARGIT and 80 (54%) with TARGIT-FX, across 41 patients. Across implants, the TARGIT-FX achieved higher mean V100% (+2.8%, P = .0019), and across patients, the TARGIT-FX achieved higher D90 (+2.0 Gy, P = .037) and higher D98 (+2.7 Gy, P = .016) compared with the original TARGIT. Doses to organs at risk were overall similar between templates. Procedure times for TARGIT-FX implants were 30% shorter on average than for those using the original TARGIT (P < .0001), and 28% shorter on average for the subset of implants with high-risk clinical target volume ≥30 cc (P = .013). All residents (100%, N = 6) surveyed regarding the TARGIT-FX indicated ease-of-use for needle insertion and interest in applying the technique in future practice.

CONCLUSIONS

The TARGIT-FX achieved shorter procedure times with increased tumor coverage and similar normal tissue sparing compared with the previously applied TARGIT and illustrates the potential of 3D printing to enhance efficiency and shorten the learning curve for intracavitary/interstitial procedure technique in cervical cancer brachytherapy.

EviGUIDE - a tool for evidence-based decision making in image-guided adaptive brachytherapy for cervical cancer

PURPOSE

To develop a novel decision-support system for radiation oncology that incorporates clinical, treatment and outcome data, as well as outcome models from a large clinical trial on magnetic resonance image-guided adaptive brachytherapy (MR-IGABT) for locally advanced cervical cancer (LACC).

METHODS

A system, called EviGUIDE, was developed that combines dosimetric information from the treatment planning system, patient and treatment characteristics, and established tumor control probability (TCP), and normal tissue complication probability (NTCP) models, to predict clinical outcome of radiotherapy treatment of LACC. Six Cox Proportional Hazards models based on data from 1341 patients of the EMBRACE-I study have been integrated. One TCP model for local tumor control, and five NTCP models for OAR morbidities.

RESULTS

EviGUIDE incorporates TCP-NTCP graphs to help users visualize the clinical impact of different treatment plans and provides feedback on achievable doses based on a large reference population. It enables holistic assessment of the interplay between multiple clinical endpoints and tumour and treatment variables. Retrospective analysis of 45 patients treated with MR-IGABT showed that there exists a sub-cohort of patients (20%) with increased risk factors, that could greatly benefit from the quantitative and visual feedback.

CONCLUSION

A novel digital concept was developed that can enhance clinical decision- making and facilitate personalized treatment. It serves as a proof of concept for a new generation of decision support systems in radiation oncology, which incorporate outcome models and high-quality reference data, and aids the dissemination of evidence-based knowledge about optimal treatment and serve as a blueprint for other sites in radiation oncology.

A practical guide to hybrid interstitial/intracavitary brachytherapy for locally-advanced cervical cancer

PURPOSE

In select cases of locally advanced cervical cancer, a hybrid brachytherapy (HBT) approach consisting of a combined intracavitary (IC)/insterstitial (IS) implant can yield improved target coverage and/or decreased organ at risk dose compared to IC techniques while limiting invasiveness compared to IS techniques.

METHODS AND MATERIALS

The technique involves placement of transvaginal and/or perineal needles in addition to the tandem and ring/ovoids using either a specialized applicator or free-hand placement. Following applicator and needle placement, brachytherapy may then be planned using principles similar to IC or IS techniques. During treatment planning, it can be helpful to obtain both MRI and CT imaging, as plastic MRI-compatible needles do not show up well on MRI.

RESULTS

In patients where acceptable target coverage cannot be achieved using IC alone or doses to nearby OAR are too high, HBT should be evaluated. HBT can improve both dose to target and OAR while sparing patients the morbidity of perineal template-based interstitial brachytherapy. Specific scenarios where HBT may be preferred include bulky residual primary tumor especially with poor response to EBRT, extension into the lateral parametrium, vaginal extension of tumor, and an asymmetric target. Use of HBT can typically permit extension of dose coverage by an additional 1-2 cm beyond what can be achieved with an IC alone technique.

CONCLUSION

HBT allows for improved therapeutic ratio by improving target volume coverage and/or lowering doses to OARs. Brachytherapists should be trained on the practical aspects of administering HBT to be able to offer a less invasive and impactful treatment option when appropriate.

Boost modalities in cervical cancer: dosimetric comparison between intracavitary BT vs. intracavitary + interstitial BT vs. SBRT

PURPOSE / OBJECTIVE

This study compares the dosimetric plans of three distinct boost modalities in cervical cancer (CC): intracavitary (IC) with tandem/ovoids brachytherapy (BT), IC + interstitial (IS) BT, and Stereotactic-Body-Radiotherapy (SBRT). The aim is to determine the dosimetric impact in terms of target coverage and organ at risk (OAR) doses.

MATERIALS AND METHODS

24 consecutive IC + IS BT boost treatment plans were retrospectively identified. For each plan included, two additional plans were created: IC-BT and SBRT. Importantly, no planning target volume (PTV) or planning (organ at) risk volume (PRV) margins were generated, therefore all structures were identical for any boost modality. Two different normalizations were performed: (1) Normalization to the target: prescription of 7.1 Gy to the D90% (defined as the minimum dose covering 90%) of the high-risk clinical target volume (HR-CTV); (2) Normalization to the OARs. HR-CTV coverage and OARs sparing were compared. The equivalent doses in 2 Gy fractions (EQD2) of EBRT and BT for CTV-HR and OARs were calculated using the linear-quadratic model with α/β of 10 (EQD2₁₀) and 3 (EQD2₃), respectively RESULTS: A total of 72 plans were investigated. In the first normalization, the mean EQD2_3-D2cc (defined as the minimal dose of the 2 cc) of OAR was significantly higher in the IC-BT plans, and the bladder D2cc hard constraint could not be reached. IC + IS BT leads to a 1 Gy mean absolute decrease of bladder EQD2₃-D2cc (relative dose: -19%), allowing to reach the hard constraint. SBRT (without PTV) delivers the lowest EQD2₃-D2cc to the OAR. In the second normalization, IC-BT provides a significantly lower dose to the EQD2₁₀-D90% (6.62 Gy) and cannot achieve the coverage goal. SBRT (without PTV) yields the highest dose to the D90% of HR-CTV and a significantly lower EQD2₁₀-D50% and D30%.

CONCLUSION

The key dosimetric benefit of BT over SBRT without PTV is a significantly higher D50% and D30% in the HR-CTV, which increases the local and conformal dose to the target. IC + IS BT vs. IC-BT provides significantly better target coverage and a lower dose to the OARs, making it the preferred boost modality in CC.

ESGO/ESTRO quality indicators for radiation therapy of cervical cancer

BACKGROUND

The European Society of Gynaecological Oncology (ESGO) has previously defined and established a list of quality indicators for the surgical treatment of cervical cancer. As a continuation of this effort to improve overall quality of care for cervical cancer patients across all aspects, ESGO and the European SocieTy for Radiotherapy and Oncology (ESTRO) initiated the development of quality indicators for radiation therapy of cervical cancer.

OBJECTIVE

To develop a list of quality indicators for radiation therapy of cervical cancer that can be used to audit and improve clinical practice by giving to practitioners and administrators a quantitative basis to improve care and organizational processes, notably for recognition of the increased complexity of modern external radiotherapy and brachytherapy techniques.

METHODS

Quality indicators were based on scientific evidence and/or expert consensus. The development process included a systematic literature search for identification of potential quality indicators and documentation of scientific evidence, consensus meetings of a group of international experts, an internal validation process, and external review by a large international panel of clinicians (n = 99).

RESULTS

Using a structured format, each quality indicator has a description specifying what the indicator is measuring. Measurability specifications are detailed to define how the quality indicators will be measured in practice. Targets were also defined for specifying the level which each unit or center should be aiming to achieve. Nineteen structural, process, and outcome indicators were defined. Quality indicators 1-6 are general requirements related to pretreatment workup, time to treatment, upfront radiation therapy, and overall management, including active participation in clinical research and the decision making process within a structured multidisciplinary team. Quality indicators 7-17 are related to treatment indicators. Quality indicators 18 and 19 are related to patient outcomes.

DISCUSSION

This set of quality indicators is a major instrument to standardize the quality of radiation therapy in cervical cancer. A scoring system combining surgical and radiotherapeutic quality indicators will be developed within an envisaged future ESGO accreditation process for the overall management of cervical cancer, in an effort to support institutional and governmental quality assurance programs.

ESGO/ESTRO quality indicators for radiation therapy of cervical cancer

BACKGROUND

The European Society of Gynaecological Oncology (ESGO) has previously defined and established a list of quality indicators for the surgical treatment of cervical cancer. As a continuation of this effort to improve overall quality of care for cervical cancer patients across all aspects, ESGO and the European SocieTy for Radiotherapy and Oncology (ESTRO) initiated the development of quality indicators for radiation therapy of cervical cancer.

OBJECTIVE

To develop a list of quality indicators for radiation therapy of cervical cancer that can be used to audit and improve clinical practice by giving to practitioners and administrators a quantitative basis to improve care and organizational processes, notably for recognition of the increased complexity of modern external radiotherapy and brachytherapy techniques.

METHODS

Quality indicators were based on scientific evidence and/or expert consensus. The development process included a systematic literature search for identification of potential quality indicators and documentation of scientific evidence, consensus meetings of a group of international experts, an internal validation process, and external review by a large international panel of clinicians (n=99).

RESULTS

Using a structured format, each quality indicator has a description specifying what the indicator is measuring. Measurability specifications are detailed to define how the quality indicators will be measured in practice. Targets were also defined for specifying the level which each unit or center should be aiming to achieve. Nineteen structural, process, and outcome indicators were defined. Quality indicators 1-6 are general requirements related to pretreatment workup, time to treatment, upfront radiation therapy, and overall management, including active participation in clinical research and the decision making process within a structured multidisciplinary team. Quality indicators 7-17 are related to treatment indicators. Quality indicators 18 and 19 are related to patient outcomes.

DISCUSSION

This set of quality indicators is a major instrument to standardize the quality of radiation therapy in cervical cancer. A scoring system combining surgical and radiotherapeutic quality indicators will be developed within an envisaged future ESGO accreditation process for the overall management of cervical cancer, in an effort to support institutional and governmental quality assurance programs.

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.

Outcome analysis of HDR compared to PDR IGABT in locally advanced cervical cancer: a single-center cohort analysis

PURPOSE

This monocentric study aimed to assess the impact of technical advancement in brachytherapy (BT) on local control (LC) and cancer-specific survival (CSS) in locally advanced cervical cancer (LACC).

METHODS

Since 2010, 211 patients with LACC have been treated with 45/50.4 Gy or 60 Gy radiochemotherapy (RTCT) followed by image-guided adaptive brachytherapy (IGABT) at the authors' institution. In 2013, combined intracavitary and interstitial brachytherapy (BT IC/IS) was implemented and in 2018, pulsed-dose-rate BT (PDR-BT) was replaced by high-dose-rate BT (HDR-BT). LC, CSS, and morbidity according to the RTOG/EORTC scoring system were analyzed. Dose-volume parameters for the high-risk clinical target volume (HRCTV) and organs at risk (OAR) were reported.

RESULTS

While 27 (12.8%) patients died of LACC, complete local remission was achieved in 199 (94.3%). Local relapse decreases with a high D95 in the HRCTV (hazard ratio, HR = 0.85, p = 0.0024). D95 in the HRCTV is lower after 60 Gy even if interstitial BT is used. Mean D95 in the HRCTV is 78.2 Gy, 83.3 Gy, and 83.4 Gy with PDR-BT IC, PDR-BT IC/IS, and HDR-BT IC/IS, respectively, after 45/50.4 Gy. D2 cc of OARs is significantly reduced by using interstitial BT. The mean rectum and sigmoid D2 cc are about 61.5 Gy with PDR-BT IC/IS and significantly decreased with HDR-BT IC/IS. This translates into a low fistula incidence. A very low rate of severe gastrointestinal (3.4%) and genitourinary (2.3%) toxicity was observed with HDR-BT IC/IS.

CONCLUSION

This large monocentric study provides further evidence that implementation of BT IC/IS has an impact on D95 in the HRCTV, LC, and CSS. There are no differences between HDR and PDR in terms of efficacy, D95 in the HRCTV, and toxicity grade ≥ 3.

A novel approach for Venezia ovoid commissioning with a comprehensive analysis of source positions in high-dose-rate brachytherapy

PURPOSE

The lunar design of a Venezia ovoid makes commissioning of the applicator very challenging with traditional autoradiography. In this study, we propose a novel solution to ovoid commissioning and a quality assurance (QA) workflow to effectively assess the entire source path.

METHODS AND MATERIALS

A two-step commissioning process, using electron radiation and radiochromic films, was developed to verify the most distal source position. The ovoid was first attached to a film and was irradiated with a 12 MeV linac beam. This process was repeated on a separate, unexposed film, followed by irradiating it with a HDR source at the most distal position. Two lengths, including the ovoid thickness and the distance between the irradiated spot and the ovoid's outer surface, were obtained from the films' intensity maps. The offset value was calculated from the subtraction of the two measured lengths. Besides acquiring the offset, a source positional simulator (SPS) and a series of planar x-rays from two orthogonal orientations were used to characterize source movement within the ovoid.

RESULTS

Compared to x-ray-based autoradiography, the electron exposure significantly improved the ovoid's visibility on film. Our approach did not use surrogate, which further improved measurement outcomes by decreasing inherent uncertainties. The SPS results suggested the source movement was complex within the cervicovaginal area, but it was predictable with the proposed QA workflow.

CONCLUSION

We introduced a novel, surrogate-free method to commission the Venezia ovoid, which facilitated a manual applicator reconstruction. Additionally, we recommended QA multiple source positions to safely use the ovoid in clinical settings.

Commissioning and Dosimetric Results of an Indigenously Developed Intra-Vaginal Template for Interstitial Plus Intracavitary High dose Rate Image-Guided Brachytherapy of Advanced Cervix Cancer

Aim

The goal of this study is to discuss the commissioning and dosimetric parameters achieved during the clinical implementation of an indigenously developed intracavitary (IC) plus interstitial (IS) template for high dose rate (HDR) image-guided brachytherapy (IGBT) in cancer (Ca) cervix. We want to discuss our achieved values of cumulative equi-effective doses (EQD2) for high-risk clinical target volume (HRCTV) and organ at risk (OAR) and compare it with available published results.

Materials and Methods

Medanta anterior oblique/lateral oblique template has a total of 19 needles including the central tandem. For commissioning the template with needles, the indigenously made acrylic phantom was used. Oblique and straight needles were placed inside the acrylic phantom and a computed tomography (CT) scan was performed. Sixteen patients were treated in HDR IGBT using this template after external-beam radiotherapy. The IGBT plans were evaluated based on EQD2 of target coverage i.e., dose received by 98% (D98%_HRCTV), 90% (D90%_HRCTV), and 50% (D50%_HRCTV) volume of HRCTV, and dose received by 2 cc (D2cc) and 0.1 cc (D0.1cc) of OAR using linear quadratic (LQ) radiobiological model.

Results

The autoradiographic in radiochromic film shows that the distance between the needle tip and the middle of the source position is 6 mm. The mean D98%_HRCTV and D90%_HRCTV was 76.8 Gy (range: 70-87.7 Gy, P < 0.01) and 84.49 Gy (range: 76.6-96.7 Gy, P < 0.01), respectively. Mean EQD2 of D2cc of the bladder, rectum, and sigmoid was 85.6 Gy (range: 77.5-99.6 Gy, P < 0.03), 74.3 Gy (range: 70.9-76.7 Gy, P < 0.05), and 58.3 Gy (range: 50.6-67.9 Gy, P = 0.01), respectively. The mean total reference air kerma at a 1 m distance is 0.489cGy (range: 0.391-0.681cGy).

Conclusions

The indigenously developed template could attain satisfactory standards in terms of set parameters for commissioning and acceptable dose volume relations in our clinical use for treating the advanced Ca cervix patients who need IC + IS type of HDR IGBT. The comparative analysis with contemporary applicators was acceptable.

The changing role for extended resections in an era of advanced radiotherapy techniques and novel therapies in gynaecological malignancy

Pelvic exenteration, first described in 1948 and subsequently refined, may be offered as a last hope of cure to patients with recurrent or locally advanced pelvic tumours, where radiotherapy is not an option. It is a complex, morbid, ultra-radical procedure involving en-bloc resection of the female reproductive organs, lower urinary tract, and a portion of the rectosigmoid. This article discusses the evolution of and current indications for pelvic exenteration in gynaecologic oncology as well as the reasons for its decline: primary and secondary prevention of cervical cancer (the recurrence of which is the most common indication for exenteration); improvements in treatment of cervical, endometrial, vaginal and vulvar cancer in the primary and recurrent setting; and the advent of novel therapies.

Change in image-guided planning strategies over time impacts oncologic and survival outcomes for intracavitary cervical cancer brachytherapy

PURPOSE

Intracavitary cervical brachytherapy (BT) has transitioned from a two-dimensional nonvolumetric (NV) dosimetry system to three-dimensional computed tomography (CT) and/or magnetic resonance imaging (MRI)-based planning techniques. The purpose of this study is to retrospectively evaluate the relative improvements in image-guided planning strategies over time with regards to dosimetry, survival, and toxicity.

METHODS AND MATERIALS

A single site retrospective review of 95 locally advanced cervical cancer patients treated with concurrent chemoradiation and high dose rate BT from 2009 to 2016 were divided into three BT planning groups: point-A based NV dosimetry using CT imaging (n = 37), CT-based volumetric dosimetry (n = 33), and MRI-based volumetric dosimetry (n = 25). Overall survival (OS), progression free survival (PFS), and pelvic control (PC) at 5 years were plotted using Kaplan-Meier curves. Univariate and multivariate (MVA) cox proportional-hazards models calculated hazard-ratios (HZ). Finally, acute and late grade 3-4 toxicities were compared between the cohorts.

RESULTS

Both MRI and CT had significantly less D2cc to bowel (p < 0.001) and sigmoid (p < 0.001) compared to NV-based planning. On MVA, age (<60 vs. ≥60 years) was significant for worse 5-year OS (HZ: 2.48) and PC (HZ: 5.25). MRI, with NV as the reference, had significantly improved 5-year OS (HZ: 0.26), PFS (HZ: 0.34) and PC (HZ: 0.16). There was no significant difference in grade ≥3 toxicities between the cohorts.

CONCLUSIONS

CT and MRI-based 3D planning had significantly less D2cc to bowel and sigmoid. MRI-based planning had significant improvement in 5-year OS, PFS, and LC compared to NV on MVA.

Now is it time to implement spacers in cervical cancer brachytherapy?

Although the international study on MRI-guided brachytherapy in cervical cancer (EMBRACE-I) demonstrated excellent local control regardless of the T stage, up to 14.6% of grade 3-5 late radiation-related toxicities were observed, which is unacceptable. While the efficacy of hydrogel spacers has been established in prostate radiotherapy, its implementation speed in cervical cancer brachytherapy is relatively slow, despite the fact that several articles have reported its efficacy in cervical cancer brachytherapy. The authors believe that using a spacer in cervical cancer brachytherapy and brachytherapy for other gynecologic malignancies will reduce late radiation-related toxicity and improve patients' quality of life; therefore, its rapid implementation is required.

Japanese Society for Radiation Oncology Consensus Guidelines of combined intracavitary and interstitial brachytherapy for gynecological cancers

It has been postulated that the combination of intracavitary and interstitial brachytherapy (IC/IS) is effective and safe for large and irregularly shaped uterine cervical cancer patients. However, due to its invasiveness compared to conventional intracavitary brachytherapy (ICBT), it has to be said that the implementation speed of IC/IS is slow. Until now, there have been no guidelines for required equipment, human resources, and procedural guide focusing solely on IC/IS. The purpose of this guideline is to provide radiation oncologists and medical physicists who wish to start IC/IS with practical and comprehensive guidance for a safe IC/IS introduction and to help accelerate the spread of the utilization of IC/IS nationwide. This is the English translation of the Japanese IC/IS Guidelines, and it was created in an effort to share the Japanese approach to the management of locally advanced uterine cervical cancer worldwide.

Brachytherapy workflow for locally advanced cervical cancer: A survey of Canadian Medical Physicists

PURPOSE

To report on brachytherapy (BT) workflows for image-based treatments of locally advanced cervical cancer (CC) in Canada.

METHODS

Medical Physicists in every Canadian cancer center were contacted and those with a CC-BT program were emailed a 44-item electronic questionnaire surveying workflow patterns including: fractionation schedules, prescription, equipment, imaging, and treatment delivery.

RESULTS

Of 47 centers contacted, all 34 who performed CC-BT participated in the survey. Brachytherapy boost, following external beam treatments, was delivered using high-dose-rate (HDR); one center also used pulsed-dose-rate. Intracavitary and/or interstitial treatments were done in 47% centers for 25-80% of their patients. All centers used image-based planning: CT (32%), CT planned with MRI for contouring (47%), MRI (18%), or cone beam CT (3%). For those performing volume-based planning (74%), the contours commonly included Clinical Target Volume (CTV)-High Risk (HR), CTV-Intermediate Risk, rectum, sigmoid, and bladder. The most common HDR dose-fractionation schedule was 7 [4.6 - 10] Gy in 4 [3 - 6] fractions with radiobiological dose prescriptions performed in 62% centers. Medical physics contribution was significant during most activities along the BT treatment pathway in all centers, especially in planning (88%), second checks (68%), and during treatment delivery (88%).

CONCLUSIONS

Compared to previous surveys, there is an increasing trend in the use of image-based volumetric planning, interstitial procedures, and radiobiological dose prescription. Cervical cancer brachytherapy in Canada is becoming more streamlined with the use of international practice guidelines. Involvement of medical physicists is vital to all stages of CC-BT, including program implementation, routine quality control, dosimetry, and treatment delivery.

Clinical advantage and outcomes of computed tomography-based transvaginal hybrid brachytherapy performed only by sedation without general or saddle block anesthesia

BACKGROUND

Three-dimensional image-guided brachytherapy is the standard of care in cervical cancer radiotherapy. In addition, the usefulness of the so-called "hybrid brachytherapy (HBT)" has been reported, which involves the addition of needle applicators to conventional intracavitary brachytherapy for interstitial irradiation.

AIM

To evaluate the clinical outcomes of CT-based HBT consisting of transvaginal insertion of needle applicators (CT-based transvaginal HBT) and only intravenous sedation without general or saddle block anesthesia.

METHODS AND RESULTS

This is a retrospective chart review of patients who received definitive radiotherapy, including CT-based transvaginal HBT, between February 2012 and July 2019. The inclusion criteria were as follows: (i) histologically diagnosed disease, (ii) untreated cervical cancer, (iii) International Federation of Gynecology and Obstetrics (FIGO) stage IB1-IVA disease in the 2008 FIGO staging system, and (iv) patients who underwent CT-based transvaginal HBT at least once in a series of intracavitary brachytherapy. Overall, 54 patients fulfilled the eligibility criteria in the present study. The median follow-up period was 32 (IQR, 19-44) months. No patient complained of symptoms such as persistent bleeding or abdominal pain after the treatment. The 3-year local control (LC), disease-free survival, and overall survival rates for all 54 patients were 86.6%, 60.3%, and 90.7% (95% CI [81.3%-100.0%]), respectively. The 3-year LC rate was 87.7% in patients with FIGO III-IVA and 90.4% in tumor size >6.0 cm. The incidence rate of late adverse events, grade ≥3, in the rectum and bladder was 0% and 1.8%, respectively. In the dose-volume histogram analyses, transvaginal HBT increased the dose of HR-CTV_D90 by ~7.5% without significantly increasing the dose of organs at risk.

CONCLUSION

Considering the favorable clinical outcomes, CT-based transvaginal HBT may be a good option for treating cervical cancer.

Advances in Radiation Oncology for the Treatment of Cervical Cancer

Background: Over the past two decades, there has been significant advancement in the management of cervical cancer, particularly in the domain of definitive chemoradiotherapy for locally advanced cervical cancer (LACC). Indeed, radiation treatment paradigms have shifted from a two-dimensional (2D) approach solely based on anatomical bony landmarks, to an image-guided three-dimensional (3D) approach, with the goal of delivering doses more precisely to clinical targets with an increased sparing of organs-at-risk. Methods: This is a narrative review on the advances in radiation technologies for the treatment of cervical cancer. Using the PubMed database, we identified articles published in English up until November 18, 2021 on the treatment of LACC with external beam radiotherapy (EBRT) and brachytherapy. A search of the Clinicaltrials.gov and Clinicaltrialsregister.eu retrieved information on ongoing clinical trials on the topic of combined immunotherapy and radiotherapy in cervical cancer. Results: We highlight the historical evolution from the use of 2D radiotherapy to 3D-conformal radiotherapy, and then intensity modulated radiotherapy (IMRT) for the delivery of EBRT. We also discuss advances in brachytherapy, notably the transition to 3D image-guided adaptive brachytherapy (3D-IGABT). In this context, we highlight large cohort studies that were recently constructed and have shown significant improvement in local control and treatment-related toxicities with 3D-IGABT. Finally, we discuss other advances in the field, notably the use of stereotactic body radiotherapy (SBRT) as a substitute to brachytherapy, and the addition of immunotherapy to chemoradiation. Conclusions: The use of IG-IMRT and 3D-IGABT have considerably improved treatment outcomes and toxicity profiles for patients with LACC, and are now considered the gold standard in many countries. The use of SBRT boost as a replacement for brachytherapy has been associated with increased toxicity and decreased efficacy and should be used with caution in the context of clinical trials. New experimental approaches include the addition of immunotherapy to chemoradiation regimens.

Risk factors for late persistent fatigue after chemoradiotherapy in locally advanced cervical cancer: an analysis from the EMBRACE-I study

Objective To evaluate patient- and treatment-related risk factors for late persistent fatigue within the prospective, multi-center XXX study. Methods Fatigue was prospectively assessed (CTCAE v.3) at baseline and during regular follow-up in 993 locally advanced cervical cancer patients, after treatment with chemoradiotherapy and MRI-guided brachytherapy. Risk factors for baseline and late persistent fatigue were evaluated with multivariable logistic regression. Late persistent fatigue was defined, when either G≥1 or G≥2 was scored in at least half of follow-ups. Results Median follow-up was 57 months. Baseline fatigue G≥1/G≥2 (35.8%/6.3%, respectively) was associated with pre-existing co-morbidities, WHO Performance Status, underweight, severe pain and tumor volume. Late persistent G≥1/G≥2 fatigue (36.3%/5.8%, respectively) was associated with patient-related factors (baseline fatigue, younger age, obesity), alongside the size of irradiated volumes and the level of radiation doses from external beam radiotherapy (EBRT) and brachytherapy (EBRT: V43Gy, V57Gy; EBRT+brachytherapy: V60Gy EQD2). Large volume lymph node (LN) boost compared to no LN boost, increased the risk for late persistent fatigue G≥2 by 18% and 5% (in patients with and without baseline fatigue, respectively). The risk for late persistent fatigue G≥1 increased by 7% and 4% with V43Gy <2000cm³ versus >3000cm³ (in patients with and without baseline fatigue, respectively). Late persistent G≥1 fatigue occurred in 13% of patients without late persistent organ-related symptoms (gastro-intestinal, genito-urinary and vaginal), versus 34-43%, 50-58% and 73% in patients suffering from persistent symptoms involving 1,2 or 3 organs, respectively. Conclusion Late persistent fatigue occurs in a considerable number of patients after chemoradiotherapy. It is associated with patient-related factors, the size of volumes irradiated to intermediate and high EBRT and brachytherapy doses, and other persistent organ-related morbidity. These findings support the importance of ongoing efforts to better tailor the target dose and reduce irradiation of healthy tissue without compromising target coverage, using highly conformal EBRT and brachytherapy techniques.

Practical needle selection for Vienna-style applicators: improving therapeutic ratio in hybrid intracavitary-interstitial brachytherapy

Purpose

Hybrid intracavitary and interstitial (IC/IS) applicators improve dose distribution compared to traditional IC applicators in cervical high-dose-rate (HDR) brachytherapy. There is a learning curve to these applicators, and initial standard needle insertion patterns have not been well-established. In this study, we quantified dosimetric benefits of IC/IS applicators, and offer practical initial interstitial needle-selection, insertion depths, and dwell position recommendations.

Material and methods

Fifteen patients previously treated with a tandem and ring IC applicator and magnetic resonance (MR)-guidance were re-planned at first fraction using a digital template of Vienna-style interstitial needles. IC/IS plans maintained identical high-risk clinical target volume (HR-CTV) D_90% while reducing dose to organs at risk (OARs). To assess the validity of planning using virtual needles, virtual needle templates were overlaid on twelve clinical IC/IS plans, and the displacements between 40 physical and virtual needles were measured at 3 cm depth.

Results

The median HR-CTV volume in the present study was 19.6 cc (range, 6.6-60.5 cc). HR-CTV D_90% was maintained in all re-plans. Median bladder D_2cc decreased from 5.4 Gy per fraction to 4.8 Gy (p = 0.003); median rectum D_2cc decreased from 2.4 Gy per fraction to 2.0 Gy (p = 0.007). We suggest that a standard loading pattern should include needles in lateral channels 4, 5, and 9, 10 inserted 3 cm deep, with dwell times < 20% of the combined tandem and ring dwells. The mean displacement between planned and physical needles was 1.8 mm. All needles but three deviated less than 3.3 mm, demonstrating the validity of re-planning with virtual needles.

Conclusions

Hybrid IC/IS applicators maintain excellent D_90% coverage while improving dose to OARs compared to IC-only applicators, even in non-bulky HR-CTVs. We offer practical recommendations for needle selection, insertion depth, and relative weighting for Vienna-style applicators in small HR-CTVs. These results support previous publications, offering practical recommendations for users of Vienna-style hybrid applicators.

Knowledge-based dose prediction models to inform gynecologic brachytherapy needle supplementation for locally advanced cervical cancer

PURPOSE

The use of interstitial needles, combined with intracavitary applicators, enables customized dose distributions and is beneficial for complex cases, but increases procedure time. Overall, applicator selection is not standardized and depends on physician expertise and preference. The purpose of this study is to determine whether dose prediction models can guide needle supplementation decision-making for cervical cancer.

MATERIALS AND METHODS

Intracavitary knowledge-based models for organ-at-risk (OAR) dose estimation were trained and validated for tandem-and-ring/ovoids (T&R/T&O) implants. Models were applied to hybrid cases with 1-3 implanted needles to predict OAR dose without needles. As a reference, 70/67 hybrid T&R/T&O cases were replanned without needles, following a standardized procedure guided by dose predictions. If a replanned dose exceeded the dose objective, the case was categorized as requiring needles. Receiver operating characteristic (ROC) curves of needle classification accuracy were generated. Optimal classification thresholds were determined from the Youden Index.

RESULTS

Needle supplementation reduced dose to OARs. However, 67%/39% of replans for T&R/T&O met all dose constraints without needles. The ROC for T&R/T&O models had an area-under-curve of 0.89/0.86, proving high classification accuracy. The optimal threshold of 99%/101% of the dose limit for T&R/T&O resulted in classification sensitivity and specificity of 78%/86% and 85%/78%.

CONCLUSIONS

Needle supplementation reduced OAR dose for most cases but was not always required to meet standard dose objectives, particularly for T&R cases. Our knowledge-based dose prediction model accurately identified cases that could have met constraints without needle supplementation, suggesting that such models may be beneficial for applicator selection.

Severity and persistency of late gastrointestinal morbidity in locally advanced cervical cancer: lessons learned from EMBRACE-I and implications for the future

PURPOSE

To evaluate patient- and treatment-related risk factors for physician-assessed and patient-reported gastrointestinal (GI) symptoms after radio(chemo)therapy and image guided adaptive brachytherapy (IGABT) in locally advanced cervical cancer (LACC).

MATERIAL AND METHODS

Of 1416 patients from the XXX study, 1199 and 1002 were prospectively evaluated using physician-assessed (CTCAE) and patient-reported (EORTC) GI symptoms, respectively. CTCAE severe grade (G≥3) events were pooled according to the location in the GI tract (anus/rectum, sigmoid and colon/small bowel). CTCAE G≥2 and EORTC "very much" and "quite a bit"+"very much" scores (≥"quite a bit") were analyzed for individual symptoms with Cox regression. Logistic regression was used for persistent G≥1 and EORTC ≥"quite a bit" symptoms, defined if present in at least half of follow-ups.

RESULTS

Incidence of G≥3 events was 2.8%, 1.8% and 2.3% for G≥3 anus/rectum, sigmoid and colon/small bowel events, respectively. Among G≥2 symptoms, diarrhea and flatulence were the most prevalent (8.4% and 9.9%, respectively). Among patient-related factors, baseline morbidity, increasing age, smoking status and low body-mass-index were associated to GI symptoms with different impact. Among treatment-related factors, rectum D_2cm3 and ICRU recto-vaginal reference point (RV-RP) correlated with G≥3 anus/rectum events, and moderate/persistent diarrhea, proctitis, bleeding, abdominal cramps and difficulty in bowel control. Bowel D_2cm3 correlated with G≥3 sigmoid and colon/small bowel events, and moderate/persistent diarrhea and flatulence. For external beam radiotherapy (EBRT), prescription dose correlated with G≥3 anus/rectum, diarrhea and difficulty in bowel control. Patients with large lymph-node boost (V57Gy) were at higher risk for G≥3 sigmoid events, moderate/persistent diarrhea, proctitis and cramps.

CONCLUSION

The analysis showed that both EBRT and IGABT contribute to GI symptoms after LACC treatment. Rectum D_2cm3, ICRU RV-RP and bowel D_2cm3 are risk factors for GI morbidity. The risk for various symptoms was lower with an EBRT prescription of 45Gy than 50Gy, and increased with larger V57Gy.

Evaluation of dose differences between intracavitary applicators for cervical brachytherapy using knowledge-based models

PURPOSE

Currently, there is a lack of patient-specific tools to guide brachytherapy planning and applicator choice for cervical cancer. The purpose of this study is to evaluate the accuracy of organ-at-risk (OAR) dose predictions using knowledge-based intracavitary models, and the use of these models and clinical data to determine the dosimetric differences of tandem-and-ring (T&R) and tandem-and-ovoids (T&O) applicators.

MATERIALS AND METHODS

Knowledge-based models, which predict organ D_2cc, were trained on 77/75 cases and validated on 32/38 for T&R/T&O applicators. Model performance was quantified using ΔD_2cc=D_2cc,actual-D_{2cc,predicted}, with standard deviation (σ(ΔD_2cc)) representing precision. Model-predicted applicator dose differences were determined by applying T&O models to T&R cases, and vice versa, and compared to clinically-achieved D_2cc differences. Applicator differences were assessed using a Student's t-test (p < 0.05 significant).

RESULTS

Validation T&O/T&R model precision was 0.65/0.55 Gy, 0.55/0.38 Gy, and 0.43/0.60 Gy for bladder, rectum and sigmoid, respectively, and similar to training. When applying T&O/T&R models to T&R/T&O cases, bladder, rectum and sigmoid D_2cc values in EQD2 were on average 5.69/2.62 Gy, 7.31/6.15 Gy and 3.65/0.69 Gy lower for T&R, with similar HRCTV volume and coverage. Clinical data also showed lower T&R OAR doses, with mean EQD2 D_2cc deviations of 0.61 Gy, 7.96 Gy (p < 0.01) and 5.86 Gy (p < 0.01) for bladder, rectum and sigmoid.

CONCLUSIONS

Accurate knowledge-based dose prediction models were developed for two common intracavitary applicators. These models could be beneficial for standardizing and improving the quality of brachytherapy plans. Both models and clinical data suggest that significant OAR sparing can be achieved with T&R over T&O applicators, particularly for the rectum.

Advances in management of locally advanced cervical cancer

Globally, cervical cancer has the fourth highest cancer incidence and mortality in women. Cervical cancer is unique because it has effective prevention, screening, and treatment options. This review discusses the current cervical cancer advances with a focus on locally advanced cervical cancer. Topics discussed include diagnostic imaging principles, surgical management with adjuvant therapy and definitive concurrent chemoradiotherapy. Emphasis is given on current advances and future research directions in radiation therapy (RT) with an emphasis on three-dimensional brachytherapy, intensity-modulated RT, image-guided RT, proton RT and hyperthermia.

Advances in External Beam Radiation Therapy and Brachytherapy for Cervical Cancer

The standard of care for the definitive treatment of locoregionally advanced cervical cancer is external beam radiation therapy (EBRT) with concurrent chemotherapy followed by a brachytherapy boost. Historically, EBRT was delivered via a two-dimensional technique based primarily on bony landmarks. This gave way to three-dimensional conformal radiation therapy, which allows for dose calculation and adjustment based on individual tumour and patient anatomy. Further technological advances have established intensity-modulated radiation therapy (IMRT) as a standard treatment modality, given the ability to maintain tumoricidal doses to target volumes while reducing unwanted radiation dose to nearby critical structures, thereby reducing toxicity. Routine image guidance allows for increased confidence in patient alignment prior to treatment, and the ability to visualise the daily position of the targets and organs at risk has been instrumental in allowing safe reductions in treated volumes. Additional EBRT technologies, including proton therapy and stereotactic body radiation therapy, may further improve the therapeutic index. In the realm of brachytherapy, a shift from point-based dose planning to image-guided brachytherapy has been associated with improved local control and reduced toxicity, with additional refinement ongoing. Here we will discuss these advances, the supporting data and future directions.

Analysis of Applicator Insertion Related Acute Side Effects for Cervical Cancer Treated With Brachytherapy

Purpose

To report applicator insertion-related acute side effects during brachytherapy (BT) procedure for cervical cancer patients.

Materials and Methods

Between November 2017 and December 2019, 407 BT fractions were performed in 125 patients with locally advanced cervical cancer. Acute side effects recorded comprised anesthesia-related side effects, mechanical-related side effects and infection, whose frequency and degree were recorded. Pain was assessed using numeric rating scale; vaginal bleeding volume was counted by weighing gauze pieces used in packing. The BT procedure comprised eight stages: anesthesia, applicator insertion, image acquisition, transport, waiting for treatment, dose delivery, applicator removal, and removed which denoted 0.5-12.0 h period after removal, with time of each stage recorded. Factors influencing acute side effects were assessed by Spearman correlation and Mann-Whitney U test.

Results

The most common acute side effect was pain, followed by vaginal bleeding. The mean scores for pain were highest during removal time, 4.9 ± 1.6 points. The mean vaginal bleeding volume was 44.4 ml during removal time. Mean total procedure time was 218.8 (175-336) min, having positive relationship with frequency of acute side effects. The total procedure time with acute side effects was longer than that without acute side effects. The longest procedure time was waiting time, 113.0 (91.0-132.0) min. More needles generated higher pain scores and larger volume of vaginal bleeding.

Conclusion

Pain and vaginal bleeding were the most common acute side effects, especially during removal time, which physicians should focus on. Shortening patients' waiting time helps to reduce the total procedure time, thus, reduce acute side effects. While meeting dose requirement, less needles are helpful to reduce acute side effects.

Characterization of combined intracavitary/interstitial brachytherapy including oblique needles in locally advanced cervix cancer

PURPOSE

To characterize and report on dosimetric outcomes of image guided adaptive brachytherapy (IGABT) using intracavitary and interstitial (IC/IS) applicators including oblique needles (O-needles) in locally advanced cervical cancer (LACC).

METHODS AND MATERIALS

Twenty LACC patients treated with radio-chemotherapy and offered IC/IS-IGABT including O-needles were analyzed. An in-house 3D-printed vaginal template was used to steer the needles parallel and obliquely in relation to the tandem, supplemented with free-hand needles if needed. Implant characteristics and loading patterns were analyzed. Using the equivalent dose in 2Gy-fractions (EQD2) concept, cumulative (EBRT+BT) V85, V75, V60Gy, targets/OARs doses and high dose volumes (150%, 200% and 300% (100% = 85 Gy EQD2₁₀)) were evaluated.

RESULTS

Median(range) tumor width at diagnosis was 5.5(3.6; 7.5)cm; CTV_HR volume was 45(23; 136)cm³ with maximum distance from tandem to CTV_HR border of 3.4(2.5; 4.8)cm. T-stage distribution was IIB/III/IVA in 6(30%)/9(45%)/5(25%) of patients. At BT, 13(65%) patients had distal parametrial/pelvic wall infiltration. Median(range) number of needles per patient was 11(8-18). Average distribution of intrauterine, vaginal and interstitial dwell times were 31%, 25% and 44%, respectively. Median(range) dwell-time per dwell position was 11(2-127)% of average point-A based standard loading. Median V_85Gy/V_150%/V_200%/V_300% were 85(38; 171)/41(21; 93)/22(12; 41)/7(4; 19) cm³; CTV_HR D_90% was 93(83; 97)Gy EQD2₁₀; bladder/rectum/sigmoid/bowel D_2cm3 were 78(64; 104)/65(52; 76)/59(53; 69)/61(47; 76)Gy EQD2₃.

CONCLUSIONS

The use of O-needles in patients with large and/or unfavorable tumors resulted in excellent target coverage and OARs sparing. Intrauterine and vaginal loadings were reduced compared to standard loading and almost half of the loading was shifted into IS needles. This was achieved with gentle loading in the majority of dwell positions.

Radiotherapy for cervical cancer: Chilean consensus of the Society of Radiation Oncology

Background

Cervical cancer is a public health problem in Latin America. Radiotherapy plays a fundamental role both as definitive or adjuvant treatment. There are important intra and inter-country differences regarding access and availability of radiotherapy facilities in this region. The aim of a study was to standardize the basic clinical and technical criteria for the radiation treatment of patients with CC in Chile and provide a guide for Latin American Radiation Oncologists.

Materials and methods

Forty-one expert radiation oncologists from the Chilean Radiation Oncology Society made a consensus using the Delphi methodology.

Results

There was a high degree of agreement for each of the recommendations. Those with the lowest percentage were related to the definition of the conformal 3D technique as the standard for definitive external radiotherapy (81%) and the criteria for extended nodal irradiation (85%).

Conclusions

These recommendations present an updated guide for radiotherapy treatment of patients with cervical cancer for Latin America. Those should be implemented according to local resources of each institution.

Hybrid tandem and ovoids brachytherapy in locally advanced cervical cancer: impact of dose and tumor volume metrics on outcomes

PURPOSE

To report the impact of dose and tumor volume metrics at brachytherapy on outcomes for locally advanced cervical cancer treated with tandem and ovoids intracavitary/interstitial brachytherapy.

MATERIAL AND METHODS

FIGO stage IB1-IIIB locally advanced cervical cancer treated with intracavitary/interstitial brachytherapy via a tandem and ovoids hybrid applicator were analyzed. Median high-risk clinical target volume (HR-CTV), rate of tumor volume reduction, EQD2 D90, organ at risk doses, and outcomes were recorded. Univariable and multivariable Cox regression was applied for survival analysis, and logistic regression was used for toxicity analysis.

RESULTS

Seventy-one patients were identified. Median follow-up was 24.9 months, with a 2-year local control of 83.6%, loco-regional control of 72.0%, and overall survival of 88.6%. Median HR-CTV D90 was 87.4 Gy (IQR = 85.7-90.2). Median HR-CTV D90 > 90 Gy10 showed a trend toward improved local control (LC) (p = 0.19). Median HR-CTV was 37.9 cm3, and median V100 was 86.5%. A median HR-CTV of ≥ 40 cm3 demonstrated worse loco-regional control (LRC) (p = 0.018) and progression-free survival (p = 0.021). Two-year LC and LRC for stage IIB patients with a median HR-CTV < 40 cm3 were significantly improved as compared to ≥ 40 cm3 at 100% and 71.8%, respectively (p = 0.019) and 100% and 56.5%, respectively (p = 0.001). However, this trend was not statistically significant for stage IIIB patients. Higher percent per day reduction in HR-CTV during brachytherapy showed improved LRC (p = 0.045). Four percent of patients experienced acute grade 3 genitourinary toxicity, 1% late grade 3 genitourinary and 1% late grade 3 gastrointestinal toxicity.

CONCLUSIONS

Tandem and ovoids intracavitary/interstitial brachytherapy provides satisfactory outcomes with modest toxicity. Higher HR-CTV D90 coverage demonstrated a trend toward improved tumor control. Tumor volume based on median HR-CTV ≥ 40 cm3 at brachytherapy was prognostic for poor outcomes, even within initial FIGO stage groups warranting caution.

MRI-guided brachytherapy for locally advanced cervical cancer: Program initiation, learning curve and dose delivery results in Kuopio University Hospital

BACKGROUND AND PURPOSE

Image guided adaptive brachytherapy, the standard treatment for locally advanced cervical cancer (LACC), is a complex medical procedure that requires an experienced multidisciplinary team. The aims of this analysis were to assess (1) the learning curve of brachytherapy team, (2) dose-volume parameters, (3) the use of an interstitial component, and (4) the overall treatment time (OTT).

MATERIALS AND METHODS

Our study cohort comprised 117 LACC patients treated in Kuopio University Hospital with magnetic resonance imaging guided intracavitary (IC) or combined intracavitary/interstitial (IC/IS) high dose rate brachytherapy during 2009-2018. Target volumes and organs at risk (OAR) were contoured according to ICRU/GEC-ESTRO recommendations. Treatment plans were optimized individually without using standard loading patterns.

RESULTS

Mean dose to 90% of the high-risk clinical target volume (HR-CTV D90) improved after the first 15 patients, however the team's learning curve to reliably fulfill the main planning aim (PA) of 85 Gy required a total 43 patients and more than 10 patients annually. Significant difference was detected between IC and IC/IS brachytherapy in achieving the PA of HR-CTV D90. Especially, HR-CTV volumes >30 cm³ benefitted from IS needles. Needle insertion did not cause serious complications. With the brachytherapy program, the OTT of patients from outside institutions was reduced to the same level as our own patients.

CONCLUSION

Brachytherapy requires good experience of multidisciplinary team and the continuous development of the program to fulfill PA and to avoid OTT prolongation. The use of IS needles is safe and improves the fulfillment of PA to target volume.

Impact of pre-brachytherapy magnetic resonance imaging on dose-volume histogram of locally advanced cervical cancer patients treated with radiotherapy including high-dose-rate brachytherapy

Purpose

This study investigated the suitability of brachytherapy technique selection based on pre-brachytherapy magnetic resonance imaging (MRI) findings in cervical cancer by evaluating dose-volume histogram parameters.

Material and methods

We retrospectively evaluated data from 61 patients with cervical cancer who underwent pre-brachytherapy MRI within 7 days before their first high-dose-rate brachytherapy treatment, selected according to pre-brachytherapy MRI findings. Combined intracavitary brachytherapy with interstitial techniques (IC/ISBT) or interstitial brachytherapy (ISBT) were favored treatments for poor-responding tumors after concurrent chemoradiotherapy, asymmetrical tumors, bulky parametrial extensions, bulky primary disease, and extensive paravaginal or distal vaginal involvement. Intracavitary brachytherapy (ICBT) was the preferred treatment for small tumors without extensive involvement of the vagina and parametrium.

Results

The median tumor size was 58 mm on pre-treatment MRI and 38 mm on pre-brachytherapy MRI. On pre-brachytherapy MRI, 13 patients had a tumor with severe vaginal invasion, 15 patients presented with an asymmetrical bulky tumor, and 4 patients had bulky residual tumors. IC/ISBT or ISBT were administered to 26 patients (43%). Median equivalent dose in 2 Gy fractions of clinical target volume D₉₀ was 70.8 Gy for all patients. Median clinical target volume D₉₀ in each brachytherapy session exceeded the prescribed dose in both patients treated with ICBT and IC/ISBT or ISBT. Median equivalent dose in 2 Gy fractions of D_2cc to the bladder, sigmoid colon, and rectum was 69.5, 52.0, and 58.4 Gy, respectively. All cases remained within the doses recommended for organs at risk.

Conclusions

Pre-brachytherapy MRI may be helpful in selecting suitable candidates for each type of brachytherapy and deliver the recommended doses to the tumor and organs at risk, particularly in cases with large tumors, poor response to concurrent chemoradiotherapy, asymmetrical tumors, severe vaginal invasion, extensive parametrial invasion, and/or corpus invasion.

Venezia applicator with oblique needles improves clinical target volume coverage in distal parametrial tumor residue compared to parallel needles only

Purpose

Residual distal parametrial involvement after radiochemotherapy is a true challenge for brachytherapists since the width and asymmetry of high-risk clinical target volume (HR-CTV) are difficult to cover properly with a standard implant.

Material and methods

Dosimetric plans of five patients treated with Venezia advanced gynecological applicator at our institution were reviewed. For each patient, we compared the original plan with a new plan where oblique needles were removed and re-optimized manually. Optimization process was halted when EQD2₁₀ D₉₀ HR-CTV reached 90 Gy, when one hard constraint to organs at risk (OARs) was reached according to the EMBRACE II protocol, or when dose-rate of one of OARs exceeded 0.6 Gy/h.

Results

Tumors were large; median HR-CTV volume was 64 cc and median distance between tandem and outer contour of HR-CTV was 40 mm. For the five patients, HR-CTV EQD2₁₀ D₉₀ was superior in the plan using oblique needles, with a median difference of 6.5 Gy (range, 1.7-8.5 Gy). Median D₉₀ HR-CTV and intermediate-risk CTV (IR-CTV) were significantly increased with oblique needles: 85.9 Gy (range, 83.2-90.3 Gy) vs. 81.5 Gy (range, 77.4-84 Gy), and 68.7 Gy (range, 66.3-72.3 Gy) vs. 67 Gy (range, 64.3-69.1 Gy), p = 0.006 for both. There were no significant differences in the dose to OARs. Plans with only parallel needles had less favorable dose distribution, with cold spots on the outer parametria and higher vaginal activation to compensate parametrial coverage in its inferior part.

Conclusions

Venezia^TM applicator permits reproducible application to increase CTV coverage in patients with distal parametrial tumor residue during brachytherapy, while maintaining acceptable dose to OARs.

Risk factors and dose-effects for bladder fistula, bleeding and cystitis after radiotherapy with imaged-guided adaptive brachytherapy for cervical cancer: An EMBRACE analysis

PURPOSE

To identify patient- and treatment-related risk factors for fistula, bleeding, cystitis, pain and difficulty in voiding in locally advanced cervical cancer patients treated with radio(chemo)therapy and image-guided adaptive brachytherapy (IGABT).

MATERIAL AND METHODS

Morbidity within the EMBRACE-I study was prospectively reported for physician-assessed (CTCAE) fistula, bleeding and cystitis and patient-reported (EORTC) pain and difficulty in voiding. Analysis of risk factors was performed in patients without bladder infiltration. Risk factors were tested with Cox regression for grade (G) ≥ 3 cystitis, for G ≥ 2 fistula, bleeding and cystitis, and for EORTC "very much" and "quite a bit" or worse.

RESULTS

Of 1416 patients enrolled, 1153 and 884 patients without bladder infiltration were evaluable for the analysis of CTCAE and EORTC items, respectively. Median follow-up was 48[3-120] months. Crude incidence rates for G ≥ 2 fistula, bleeding and cystitis were 0.7%, 2.7% and 8.8%, respectively, and 16% and 14% for "quite a bit" or worse pain and difficulty in voiding, respectively. Baseline urinary morbidity and overweight/obesity were significant risk factors for most endpoints. Bladder D_2cm3 correlated with G ≥ 2 fistula, bleeding and cystitis, while ICRU bladder point dose correlated with EORTC pain "quite a bit" or worse. An increase from 75 Gy to 80 Gy in bladder D_2cm3 resulted in an increase from 8% to 13% for 4-year actuarial estimate of G ≥ 2 cystitis.

CONCLUSION

Clinical and treatment-related risk factors for bladder fistula, bleeding and cystitis were identified within a prospective and multi-institutional setting. A dose-effect was established with bladder D_2cm3, reinforcing the importance of continued optimization during individualized IGABT planning.

Complications of intracavitary brachytherapy for gynecologic cancers and their management: A comprehensive review

Intracavitary gynecologic brachytherapy in the form of tandem-based brachytherapy and vaginal cylinder-based brachytherapy represents a fundamental component of the treatment of women with cervical or uterine cancer due to the ability to deliver a therapeutic dose of radiation with sharp dose falloff. This results in highly effective treatment in terms of oncologic outcomes with an overall favorable toxicity profile. Still, complications and side effects of brachytherapy do exist. While advances in brachytherapy techniques have led to a significant decrease in the rates of toxicity, a thorough understanding of the potential complications is crucial to ensuring optimal outcomes for women with gynecologic cancer undergoing brachytherapy. Use of equivalent dose at 2 Gy per fraction (EQD2) models has allowed incorporation of external beam radiotherapy dose to the brachytherapy dose leading to development of consolidated dose constraints for organs-at-risk in the modern era. This manuscript offers a comprehensive review of potential complications associated with intracavitary brachytherapy for gynecologic cancer including predictive factors, mitigation tactics, and management strategies.

Simulation-based graduate medical education in MR-guided brachytherapy for cervical cancer

PURPOSE

Brachytherapy is critical for the curative treatment of locally advanced cervical cancer. Although brachytherapy use is declining in the United States (U.S.), novel interstitial or intracavitary applicators and advances in image guidance for applicator placement and treatment planning have allowed for tumor dose escalation while reducing normal tissue toxicity. Recent survey data have suggested insufficient brachytherapy training for radiation oncology trainees in the United States. This study aimed to address these gaps by developing and piloting a simulation-based education (SBE) workshop for MR-guided cervical cancer brachytherapy.

METHODS AND MATERIALS

An SBE workshop was developed for graduate medical education (GME) trainees focusing on MR-guided brachytherapy for cervical cancer. Four hands-on stations, simulating aspects of the procedure, were led by a team of gynecological brachytherapy experts. The learners were radiation oncology residents and fellows in a U.S. GME training program. The primary outcome was feasibility, assessed by completion of the workshop within the time constraints of the curriculum. Learners completed preworkshop and postworkshop surveys to provide information on efficacy.

RESULTS

The workshop was successfully completed in a 1-h block of GME didactic time. Ten trainees completed all four stations, and all completed preworkshop and postworkshop surveys, which showed improvements in knowledge and technical proficiency. Feedback was positive, and trainees requested additional learning opportunities.

CONCLUSIONS

This study showed that GME-focused SBE in MR-guided cervical cancer brachytherapy was feasible. SBE provided a nonclinical environment in which to practice aspects of MR-guided brachytherapy. Ongoing work includes collaboration with other U.S. institutions. Future studies should focus on international adaptation.

Predicting which patients may benefit from the hybrid intracavitary+interstitial needle (IC/IS) applicator for advanced cervical cancer: A dosimetric comparison and toxicity benefit analysis

PURPOSE

The purpose of this study is to compare the predicted rate of local control and bladder and rectum toxicity rates for image-guided adaptive brachytherapy plans using a tandem and ovoid (T/O) applicator versus using a simulated hybrid intracavitary/interstitial tandem and ring applicator with needles (T/R + N) for patients with locally advanced cervical cancer (LACC).

METHODS AND MATERIALS

Patients with ≥ FIGO Stage IIB locally advanced cervical cancer treated with T/O from a single institution were included. Simulated treatment plans were created with a T/R + N applicator for the best high-risk clinical target volume (CTV) coverage and minimal dose to organs at risk. Three-year local control rate was estimated using published dose-volume effect relationships. Next, the high-risk CTV EQD2 D90 of T/R + N plans were calculated, and bladder and rectum toxicity rates were estimated. Analysis was performed in subpatient groups defined based on tumor volume and ratio of maximal and minimal tumor radii (RR) that reflects tumor shape asymmetry.

RESULTS

Improvements in predicted local control rate for the T/R + N were 0.8, 4.1, 1.6, and 3.9% for groups with tumor volume <35 cc, ≥35 cc, RR < 2.0, and ≥2.0, respectively, with the latter three being statistically significant. Predicted reductions in Grade 2-4 toxicity rates of bladder and rectum were significant in all groups except bladder toxicity in tumor volume <35 cc, when T/R + N plans were normalized to the same CTV coverage as the T/O plans. Comparing unnormalized T/R + N plans and T/O plans, predicted toxicity reductions were significant in all groups except rectum toxicity in RR ≥ 2.0. Predicted reduction of toxicity rate was larger for patients with large tumor or large tumor RR, although some reductions were relatively small.

CONCLUSIONS

Cases with large tumor (volume ≥35 cc) or large tumor asymmetry (RR ≥ 2.0) would probably benefit more from the use of hybrid applicators.

Importance of the ICRU bladder point dose on incidence and persistence of urinary frequency and incontinence in locally advanced cervical cancer: An EMBRACE analysis

PURPOSE

To identify patient- and treatment-related risk factors and dose-effects for urinary frequency and incontinence in locally advanced cervical cancer (LACC) treated with radio(chemo)therapy and image-guided adaptive brachytherapy (IGABT).

MATERIAL AND METHODS

Physician-assessed (CTCAE) and patient-reported (EORTC) frequency and incontinence recorded in the EMBRACE-I study were analysed. Risk factors analysis was performed in patients without bladder infiltration and with baseline morbidity available. Cox regression was used for CTCAE grade (G) ≥ 3 and G ≥ 2 and for EORTC "very much" and "quite a bit" or worse. Logistic regression was used for late persistent morbidity defined when CTCAE G ≥ 1 or EORTC ≥ "quite a bit" were scored in at least half of follow-ups.

RESULTS

Longitudinal data on 1153 and 884 patients were available for CTCAE and EORTC analysis, respectively. Median follow-up was 48[3-120] months. Crude incidence rates of G≥2 were 13% and 11% for frequency and incontinence, respectively. Baseline morbidity and overweight-obesity were risk factors for both symptoms. Elderly patients were at higher risk for incontinence. Patients receiving conformal-radiotherapy were at higher risk for frequency. ICRU bladder point (ICRU-BP) dose was a stronger predictor for incontinence than bladder D_2cm3. The 5-year actuarial estimate of G ≥ 2 incontinence increased from 11% to 20% with ICRU-BP doses > 75 Gy compared to ≤ 65 Gy. Frequency showed weaker associations with dose.

CONCLUSION

ICRU-BP dose, in addition to clinical parameters, is a risk factor for urinary incontinence and shows a dose-effect after radio(chemo)therapy and IGABT. ICRU-BP dose should be monitored during treatment planning alongside volumetric parameters. Frequency seems associated with larger irradiated volumes.

Dose-Volume Effects and Risk Factors for Late Diarrhea in Cervix Cancer Patients After Radiochemotherapy With Image Guided Adaptive Brachytherapy in the EMBRACE I Study

PURPOSE

To evaluate patient- and treatment-related risk factors associated with incidence and persistence of late diarrhea after radiochemotherapy and image guided adaptive brachytherapy (IGABT) in locally advanced cervical cancer.

MATERIALS AND METHODS

Of 1416 patients from the EMBRACE I study, 1199 were prospectively evaluated using physician-reported (Common Terminology Criteria for Adverse Events version 3 [CTCAEv3]) assessment for diarrhea; median follow-up 48 months. Patient-reported outcome (EORTC) was available in 900 patients. Incidence of CTCAE G≥2, G≥3, and EORTC "very much" diarrhea was analyzed with Cox proportional hazards regression. Binary logistic regression was used for analysis of persistent G≥1 and EORTC "quite a bit" - "very much" (≥"quite a bit") diarrhea, defined if present in at least half of all follow-ups.

RESULTS

Crude incidences of G≥2 and G≥3 diarrhea were 8.3% and 1.5%, respectively, and 8% of patients reported "very much" diarrhea. Persistent G≥1 and ≥"quite a bit" diarrhea was present in 16% and 7%, respectively. Patient-related risk factors were baseline diarrhea, smoking, and diabetes with hazard ratios of 1.4 to 7.3. Treatment-related risk factors included prescribed dose, V43 Gy, V57 Gy (lymph node boost), and para-aortic irradiation for external beam radiation therapy (EBRT). G≥2 diarrhea at 3 years increased from 9.5% to 19.9% with prescribed dose 45 Gy versus 50 Gy, 8.7% to 14.0% with V43 Gy <2500 cm³ versus >3000 cm³ and 9.4% to 19.0% with V57 Gy <165 cm³ versus ≥165 cm³. Brachytherapy-related bowel and rectum D_2cm3 were also associated with diarrhea.

CONCLUSION

Dose and volume effects have been established for late diarrhea after radiochemotherapy and IGABT in both CTCAE and EORTC reporting. The risk of diarrhea was lower with a pelvic EBRT prescription of 45 Gy, and higher with larger lymph node boosts volumes (ie, ≥165 cm³). The importance of EBRT volumes as determinants of late toxicity underline the need for continuous quality assurance of target contouring, dose planning, and conformity. The findings of brachytherapy dosimetric factors related to the intestines may become more important with highly conformal EBRT.

Initiatives for education, training, and dissemination of morbidity assessment and reporting in a multiinstitutional international context: Insights from the EMBRACE studies on cervical cancer

In 2008, the GEC ESTRO Gyn network launched the first multiinstitutional, observational, and prospective international study on MRI-guided brachytherapy in locally advanced cervical cancer patients (EMBRACE-I). EMBRACE-I was followed by EMBRACE-II from 2016 and ongoing. Among the aims of the EMBRACE studies are to benchmark morbidity outcomes and develop dose-volume effects and predictive models for morbidity. The EMBRACE studies collect both physician (CTCAE v.3) and patient (EORTC QLQ-C30/CX24) reported outcomes, including baseline information, in a regular follow-up schedule. The EMBRACE studies feature high numbers of patients (EMBRACE-I N = 1416, EMBRACE-II N = 1500 expected) enrolled from many institutions worldwide (EMBRACE-I n = 23, EMBRACE-II n = 45). This large-scale multiinstitutional approach offers a unique opportunity to investigate and develop new strategies for improving the quality of assessment and reporting of morbidity. This report presents an overview of the challenges and pitfalls regarding the assessment and reporting of morbidity encountered during more than a decade of development and research activities within the EMBRACE consortium. This includes the recognition and evaluation of inconsistencies in the morbidity assessment, and consequently, the provision of assistance and training in the scoring procedure to reduce systematic assessment bias. In parallel, a variety of methodological approaches were tested to comprehensively summarize morbidity outcomes, and a novel approach was developed to refine dose-effect models and risk factor analyses. The purpose of this report is to present an overview of these findings, describe the learning process, and the strategies that have consequently been implemented regarding educational activities, training, and dissemination.

Early outcomes after definitive chemoradiation therapy with Vienna/Venezia hybrid high-dose rate brachytherapy applicators for cervical cancer: A single-institution experience

PURPOSE

The Vienna and Venezia (Elekta) are hybrid intracavitary/interstitial brachytherapy (BT) applicators for cervical cancers unsuitable for intracavitary BT alone to improve target coverage or reduce critical organ dose. There is limited outcome data with the use of these applicators outside published experience of the EMBRACE group. We report feasibility and early outcomes with the use of these hybrid applicators at our institution.

METHODS AND MATERIALS

Hybrid applicators were used to treat 61 patients with cervical cancer from November 2011 to December 2019. Indications for hybrid applicator use were involvement of the vagina in 10 patients (16%), residual central or parametrial disease in 46 patients (75%), and a narrow introitus in 5 patients (9%). Toxicities were graded using the CTCAE v4.0. Outcomes were assessed with the Kaplan-Meier method.

RESULTS

Median follow-up was 16 months (IQR 9-32 mos). Median HRCTV volume was 31.6 cm³ (IQR 25-48 cm³). Median HRCTV D90 was 86.1 Gy (IQR 84.3-88.0 Gy). In 54 patients with follow-up PET/CT at 3 months, complete initial imaging response locally was seen in 46 patients.Estimated 12-month Kaplan-Meier overall survival, locoregional control, distant control, and recurrence-free survival estimates were 86.9%, 80.6%, 73.8%, and 65.9%, respectively. The 12-month incidence of Grade 3+ GI/GU chronic toxicities was 5.7%, consisting of vesicovaginal fistula, rectovaginal fistula, and ureterovesical fistula.

CONCLUSIONS

Our single-institution data support the use of the hybrid applicators, as an alternative to traditional BT applicators when clinically warranted. Use of hybrid applicators is feasible with adequate coverage of disease in the vagina and parametrium.