CT based three dimensional dose-volume evaluations for high-dose rate intracavitary brachytherapy for cervical cancer

Role of the gel spacer in safely delivering whole pelvic radiation therapy without central shielding in computed tomography-based image-guided adaptive brachytherapy for uterine cervical cancer patients

BACKGROUND

To protect the rectum and bladder from high dose exposure, the Japanese guidelines for managing uterine cervical carcinoma recommend pelvic irradiation with central shielding (CS). Conversely, the European Society for Radiotherapy and Oncology (ESTRO) and the American Brachytherapy Society (ABS) guidelines recommend delivering ≥85 Gy to high-risk clinical target volume D90 (CTVHR D90%). In this study, we investigated whether a gel spacer can enable the safe delivery of the ESTRO/ABS-recommended doses to the target while observing dose constraints for the OARs without using CS in external beam radiation therapy (EBRT).

MATERIALS AND METHODS

Twenty patients who received definitive radiation therapy without CS and were treated by brachytherapy with a gel spacer between 2017 and 2022 were retrospectively reviewed. The cumulative doses of EBRT and brachytherapy treatment outcomes and incidence of adverse events were also examined.

RESULTS

The median cumulative CTVHR D90%, rectum D2cm3, and bladder D2cm3 were 86.6 Gy, 62.9 Gy, and 72.0 Gy, respectively. The 2-year local control rate was 95%. There were no CTCAE ≥Grade 3 late gastrointestinal or genitourinary adverse events.

CONCLUSIONS

The use of gel spacer can enable ESTRO/ABS-recommended dose constraints even without using CS in EBRT, with favorable outcomes and low adverse event rates.

Effective timing of hyaluronate gel injection in image-guided adaptive brachytherapy for uterine cervical cancer: a proposal of the 'adjusted dose score'

Hyaluronate gel injection (HGI) in the rectovaginal septum and vesicovaginal septum is effective in the setting of high-dose-rate image-guided adaptive brachytherapy (IGABT) for cervical cancer. We aimed to retrospectively investigate optimal conditions for HGI to achieve optimal dose distribution with a minimum number of HGI. We classified 50 IGABT plans of 13 patients with cervical cancer who received IGABT both with and without HGI in the rectovaginal septum and vesicovaginal septum into the following two groups: plan with (number of plans = 32) and plan without (number of plans = 18) HGI. The irradiation dose parameters of high-risk clinical target volume (CTVHR) and organs at risk per fraction were compared between these groups. We also developed the adjusted dose score (ADS), reflecting the overall irradiation dose status for four organs at risk and CTVHR in one IGABT plan and investigated its utility in determining the application of HGI. HGI reduced the maximum dose to the most exposed 2.0 cm3 (D2.0 cm3) of the bladder while increasing the minimum dose covering 90% of CTVHR and the percentage of CTVHR receiving 100% of the prescription dose in one IGABT plan without causing any associated complications. An ADS of ≥2.60 was the optimum cut-off value to decide whether to perform HGI. In conclusion, HGI is a useful procedure for improving target dose distribution while reducing D2.0 cm3 in the bladder in a single IGABT plan. The ADS can serve as a useful indicator for the implementation of HGI.

Hands-on-training tailored in response to pre-questionnaire-based survey on image-guided brachytherapy effectively reduces anxiety about its implementation

This study assessed the significance of hands-on-training (HoT) and questionnaire-based surveys on 3D image-guided brachytherapy (3D-IGBT) and a combination of intracavitary and interstitial brachytherapy, the so-called 'hybrid' BT (HBT), in uterine cervical cancer. In October 2023, 29 radiation oncologists, nurses, radiologic technologists and medical physicists from 10 Japanese facilities participated in an HoT on 3D-IGBT and HBT. Questionnaires were distributed to each participant before and after the HoT, and feedback was obtained through online channels. The questionnaire response rate was 83% (24/29), with at least one participant responding from each facility. 'Insertion of applicators and needles', 'human resource shortage' and 'pain relief and sedation' were the primary concerns of radiation oncologists. 'Applicator reconstruction', ' optimization of dwell positions', ' treatment planning' and ' human resource shortages ' were the primary concerns of radiological technologists and medical physicists. The HoT content was adjusted according to the results of preliminary surveys. The concerns expressed by the participants were addressed during the lectures and practical training. Significant reductions in anxiety were observed toward all items of the 10-point self-assessment after the HoT, regardless of the profession. The average score on satisfaction with the HoT (on a 10-point scale) was 9.52 (minimum of 8 and maximum of 10). In conclusion, HoT tailored in response to a pre-questionnaire-based survey effectively reduced participants' anxiety regarding the implementation of 3D-IGBT and HBT.

Transvaginal approach combined intracavitary and interstitial brachytherapy assisted by transrectal ultrasound: results from 30 patients with locally advanced cervical cancer

PURPOSE

This study evaluated the efficacy and safety of transvaginal approach combined intracavitary and interstitial brachytherapy (IC/IS BT) assisted by transrectal ultrasound (TRUS) for treatment of locally advanced cervical cancer (LACC).

MATERIALS AND METHODS

A total of 30 patients of LACC treated with external beam radiotherapy and IC/IS BT via transvaginal approach assisted by transrectal ultrasound were observed retrospectively. The 2-year local control (LC), progression-free survival (PFS), and overall survival (OS) were analyzed using the Kaplan-Meier method. Late adverse events were also evaluated to assess the safety of IC/IS BT.

RESULTS

The median follow-up period was 22 months. The 2-year LC, PFS, and OS were 90%, 61%, and 82%, respectively. We observed no critical complications related to the IC/IS BT technique. Late adverse events of grade 3 or more included one case of grade 4 colon perforation.

CONCLUSION

Our patient series demonstrated that radiotherapy combined with transvaginal approach, TRUS-assisted IC/IS BT achieves favorable local control and safety for LACC.

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.

CT-based image-guided brachytherapy in uterine cervical cancer: Effect of tumor dose and volume on local control

BACKGROUND AND PURPOSE

To determine the optimal primary tumor dose for cervical cancer treatment using computed tomography (CT)-based image-guided brachytherapy (IGBT).

MATERIALS AND METHODS

We retrospectively reviewed 171 patients with cervical cancer who underwent both external beam radiation therapy (EBRT) and IGBT between May 2015 and December 2019. Majority of EBRT plan included central shielding technique. CT-based IGBT was performed weekly a median of three times. Magnetic resonance imaging preceded the first and third session of IGBT for target delineation.

RESULTS

The median age of the patients was 64 years (range: 30-91 years). The median follow-up time for living patients was 43 months (range: 6-76 months). The 3-year local control rates according to the International Federation of Gynecology and Obstetrics (FIGO, 2008) stages were 89%, 100%, 92%, 89%, 78%, and 100% for stages IB, IIA, IIB, IIIA, IIIB, and IVA, respectively. The median EBRT dose to the central pelvis and parametrium/pelvic wall was 41.4 Gy and 50.4 Gy, respectively. Patients who received a cumulative 2 Gy equivalent dose (EQD2) (α/β = 10 Gy) of high-risk clinical target volume (HR CTV) D90% ≥ 75 Gy achieved a long-term local control rate of 93%, compared with 80% in those who received <75 Gy (p = 0.02).

CONCLUSION

This is one of the largest CT-based IGBT series examining the treatment of cervical cancer based on the tumor dose-volume relationship. An HR CTV D90% ≥75 Gy was significantly associated with favorable local control in this study.

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.

Tumor size before image-guided brachytherapy is an important factor of local control after radiotherapy for cervical squamous cell carcinoma: analysis in cases using central shielding

We analyzed the local control (LC) of cervical squamous cell carcinoma treated by computed tomography (CT)-based image-guided brachytherapy (IGBT) using central shielding (CS). We also examined the value of tumor diameter before brachytherapy (BT) as a factor of LC. In total, 97 patients were analyzed between April 2016 and March 2020. Whole-pelvic (WP) radiotherapy (RT) with CS was performed, and the total pelvic sidewall dose was 50 or 50.4 Gy; IGBT was delivered in 3-4 fractions. The total dose was calculated as the biologically equivalent dose in 2 Gy fractions, and distribution was modified manually by graphical optimization. The median follow-up period was 31.8 months (6.3-63.2 months). The 1- and 2-year LC rates were 89% and 87%, respectively. The hazard ratio was 10.11 (95% confidence interval: 1.48-68.99) for local recurrence in those with a horizontal tumor diameter ≥ 4 cm compared to those with < 4 cm before BT. In CT-based IGBT for squamous cell carcinoma, favorable LC can be obtained in patients with a tumor diameter < 4 cm before BT. However, if the tumor diameter is ≥ 4 cm, different treatment strategies such as employing interstitial-BT for dose escalation may be necessary.

An Asian multi-national multi-institutional retrospective study comparing intracavitary versus the hybrid of intracavitary and interstitial brachytherapy for locally advanced uterine cervical carcinoma

This study is an international multi-institutional retrospective study comparing the clinical outcomes between intracavitary brachytherapy (ICBT) and the hybrid of intracavitary and interstitial brachytherapy (HBT) for locally advanced cervical cancer patients treated with definitive radiation therapy. Locally advanced cervical cancer, the initial size of which is larger than 4 cm and treated by concurrent chemoradiotherapy and image-guided adaptive brachytherapy, were eligible for this retrospective study. Patients who received HBT at least once were included in the HBT group, and patients who received only ICBT were included in the ICBT group. Anonymized data from 469 patients from 13 institutions in Japan, one from Korea and one from Thailand, were analyzed. Two hundred eighty and 189 patients were included in the ICBT group and the HBT group, respectively. Patients in the HBT group had more advanced stage, non-Scc histopathology, a higher rate of uterine body involvement, larger tumor at diagnosis, larger tumor before brachytherapy and a lower tumor reduction ratio. With a median follow-up of 51.3 months (2.1-139.9 months), 4-y local control (LC), progression-free survival (PFS) and overall survival (OS) for the entire patient population were 88.2%, 64.2% and 83%, respectively. The HBT group received a higher HR-CTV D90 than that of the ICBT group (68.8 Gy vs 65.6 Gy, P = 0.001). In multivariate analysis, the non-Scc histological subtype, HR-CTV D95 ≤ 60 Gy, reduction ratio ≤ 29% and total treatment time (TTT) ≥ 9 weeks were identified as the independent adverse prognostic factors for LC. Regarding LC, no difference was found between ICBT and HBT (4-y LC 89.3% vs 86.8%, P = 0.314). After adjustment for confounding factors by propensity score matching, no advantage of applying HBT was demonstrated regarding LC, PFS, or OS. Despite the fact that HBT patients had more adverse clinical factors than ICBT patients, HBT delivered a higher dose to HR-CTV and resulted in comparable LC.

Point-A vs. volume-based brachytherapy for the treatment of cervix cancer: A meta-analysis

BACKGROUND & PURPOSE

To report disease-free survival (DFS) for volume-based and point-A based brachytherapy (BT) in locally advanced cervical cancer.

MATERIALS & METHODS

We conducted a meta-analysis of studies assessing the effects of point-A and volume-based brachytherapy on 3-year DFS. Studies including stage I-IVA cervical cancer patients were included if standard treatment of concomitant chemo-radiotherapy and high-dose- or pulsed dose rate BT was delivered. The primary outcome was 3-year DFS, and secondary outcomes were 3-year local control (LC), 3-year overall survival (OS) and late toxicity. A random-effects subgroup meta-analysis was done.

RESULTS

In total, 5499 studies were screened, of which 24 studies with 5488 patients were eligible. There was significant heterogeneity among point-A studies (1538 patients) (I² = 82%, p < 0.05) relative to volume-based studies (3950 patients) (I² = 58, p = 0.01). The 3-year DFS for point-A and volume-based studies were 67% (95% CI 60%-73%) and 79% (95% CI 76%-82%) respectively (p = 0.001). Three-year LC for point-A and volume-based studies were 86% (95% CI 81%-90%) and 92% (91%-94%) respectively (p = 0.01). The difference in 3-year OS (72% vs. 79%, p = 0.12) was not statistically significant. The proportion of prospectively enrolled patients was 23% for point-A studies and 33% for volume-based studies. There was no difference in late grade 3 or higher gastrointestinal (3% vs. 4%, p = 0.76) genitourinary toxicities (3% vs. 3% p = 0.45) between the two groups.

CONCLUSION

Volume-based BT results in superior 3-year DFS and 3-year LC. In the absence of randomized trials, this meta-analysis provides the best evidence regarding transition to 3D planning.

3D-Image-Guided Multi-Catheter Interstitial Brachytherapy for Bulky and High-Risk Stage IIB-IVB Cervical Cancer

Simple Summary

The prognosis of locally advanced cervical cancer still remains poor. Recently, image-guided brachytherapy ameliorated local control and pelvic control in these patients. Additionally, concurrent chemoradiotherapy with interstitial brachytherapy (ISBT) demonstrated more favorable outcomes than that with intracavity brachytherapy. The purpose of our study was to evaluate the efficacy and safety of CT-MRI-guided multi-catheter ISBT for bulky (≥4 cm) and high-risk stage IIB-IVB cervical cancer. Total of 18 patients with squamous cell carcinoma received concurrent chemoradiotherapy with ISBT were assessed. Four (22.2%), seven (38.9%), and seven (38.9%) patients were diagnosed with stage II, III, and IV cervical cancer, respectively. The four-year local control, pelvic control, disease-free survival, and overall survival rates were 100%, 100%, 81.6%, and 87.8%, respectively. Although three (16.7%) patients experienced grade 3 late adverse events, no one had procedure-related complications. CT-MRI-guided multi-catheter ISBT could be a promising treatment strategy for locally advanced cervical cancer.

Abstract

This study aimed to evaluate the efficacy and safety of computed tomography-magnetic resonance imaging (CT-MRI)-guided multi-catheter interstitial brachytherapy for patients with bulky (≥4 cm) and high-risk, stage IIB–IVB advanced cervical cancer. Eighteen patients who underwent concurrent chemoradiotherapy with multi-catheter interstitial brachytherapy between September 2014 and August 2020 were enrolled. The prescribed dose of external beam radiotherapy was 45–50.4 Gy, and the brachytherapy high-dose-rate aim was 25–30 Gy per 5 fractions. The endpoints were four-year local and pelvic control rates, four-year disease-free and overall survival rates, and the adverse events rate. The median follow-up period was 48.4 months (9.1–87.5 months). Fifteen patients received concurrent cisplatin therapy (40 mg/m², q1week). Four (22.2%), seven (38.9%), and seven (38.9%) patients had stage II, III, and IV cervical cancer, respectively. Pelvic and para-aortic lymph node metastases were observed in 11 (61.1%) and 2 (11.1%) patients, respectively. The median pre-treatment volume was 87.5 cm³. The four-year local control, pelvic control, disease-free survival, and overall survival rates were 100%, 100%, 81.6%, and 87.8%, respectively. Three (16.7%) patients experienced grade 3 adverse events, and none experienced grade 4–5 adverse events. CT-MRI-guided multi-catheter interstitial brachytherapy could be a promising treatment strategy for locally advanced cervical cancer.

Combined Interstitial and Intracavitary High-Dose Rate Brachytherapy of Cervical Cancer

High-dose-rate brachytherapy by remote afterloading is now performed under three-dimensional image guidance by CT or MRI. Three-dimensional image-guided brachytherapy in cervical cancer disclosed that the traditional intracavitary brachytherapy by Manchester method cannot deliver an adequate dose to the large tumor with resulting local recurrence. To improve the local control rate, combined interstitial and intracavitary (hybrid) brachytherapy can increase the dose to the large parametrial involvement without increasing the dose to the rectum and bladder. Whether hybrid brachytherapy can be performed safely on a multi-institutional basis remains to be studied. From 2015, phase I/II study of hybrid brachytherapy was launched in Japan, and it was revealed that hybrid brachytherapy can be performed safely and with a high quality of radiation dose distribution in a multi-institutional study. In Japan, the number of patients undergoing hybrid brachytherapy in cervical cancer is rapidly rising. Education and clinical trial are very important to establish hybrid brachytherapy in the management of cervical cancer.

Comparative dosimetry of brachytherapy treatment planning between a volume-based plan by CT and a point-based plan by TAUS in CT datasets for brachytherapy

Aim:

To evaluate comparative dosimetry of brachytherapy treatment planning between a volume-based plan by computed tomography (CT) and a point-based plan by transabdominal ultrasound (TAUS) in CT datasets for brachytherapy.

Materials and methods:

From 2019 to 2021, 59 different datasets of CT images were collected from 38 patients treated by intracavitary brachytherapy with tandem ovoid or tandem ring applicators. At that time, TAUS was performed to prevent uterine perforation and to evaluate topography of the cervix during application. In volume-based planning by CT, the target dose was used to keep the dose at 90% of high-risk clinical target volume (HR-CTV), to give a dose of at least 7Gy, while in the point-based plan by TAUS, the target dose was used to keep the minimum dose to eight cervix reference points (measured by TAUS), to give a dose of at least 7Gy. The doses to targets and organs at risk were evaluated and compared between volume-based planning by CT and the point-based plan by TAUS.

Results:

Of 59 fractions, a tandem ovoid applicator was used in 48 fractions (81·3%). In the volume-based plan by CT, the mean doses to HR-CTV(D90), intermediate-risk clinical target volume (IR-CTV)(D90), bladder(D2cc), rectum(D2cc) and sigmoid colon(D2cc) were 7·0, 3·9, 4·9, 2·9 and 3·3 Gy, respectively, while in the point-based plan by TAUS, the mean doses to HR-CTV(D90), IR-CTV(D90), bladder(D2cc), rectum(D2cc) and sigmoid colon(D2cc) were 8·2, 4·6, 5·9, 3·4 and 3·9 Gy, respectively. The percentages of mean dose differences between TAUS and CT of HR-CTV(D90), IR-CTV(D90), bladder(D2cc), rectum(D2cc) and sigmoid colon(D2cc) were 17·7, 19·5, 20·5, 19·5, 21·3 and 19·8%, respectively. With the target dose to the point-based plan by TAUS (7 Gy to the cervix reference points), this was close to D98 of HR-CTV with a mean percentage of difference of 0·6%.

Findings:

The point-based plan by TAUS showed higher values to targets and organs at risk than the volume-based plan by CT. With the point-based plan by TAUS, it was close to D98 of HR-CTV.

Dosimetric feasibility of computed tomography-based image-guided brachytherapy in locally advanced cervical cancer: a Japanese prospective multi-institutional study

The aim of this study was to assess the feasibility of planning dose-volume histogram (DVH) parameters in computed tomography-based 3D image-guided brachytherapy for locally advanced cervical cancer. In a prospective multi-institutional study, 60 patients with stage IIA2-IVA cervical cancer from eight institutions were treated with external beam radiotherapy using central shielding and intracavitary or hybrid (combined intracavitary/interstitial) brachytherapy (HBT). The dose constraints were set as a cumulative linear quadratic equivalent dose (EQD2) of at least 60 Gy for high-risk clinical target volume (HR-CTV) D90, D2cc ≤ 75 Gy for rectum, D2cc ≤ 90 Gy for bladder and D2cc ≤ 75 Gy for sigmoid. The median HR-CTV D90 was 70.0 Gy (range, 62.8-83.7 Gy) in EQD2. The median D2cc of rectum, bladder and sigmoid was 57.1 Gy (range, 39.8-72.1 Gy), 68.9 Gy (range, 46.5-84.9 Gy) and 57.2 Gy (range, 39.2-71.2 Gy) in EQD2, respectively. In 76 of 233 sessions (33%), 23 patients underwent HBT, and the median number of interstitial needles was 2 (range, 1-5). HBT for a bulky HR-CTV (≥40 cm3) significantly improved the HR-CTV D90 compared with intracavitary brachytherapy alone (P = 0.010). All patients fulfilled the dose constrains for target and at risk organs by undergoing HBT in one-third of sessions. We conclude that the planning DVH parameters used in our protocol are clinically feasible.

Non-anesthetist-administered moderate sedation with midazolam and fentanyl for outpatient MRI-aided hybrid intracavitary and interstitial brachytherapy in cervix cancer: a single-institution experience

Purpose

The aim of the study was to determine the feasibility of interstitial brachytherapy under non-anesthetist-administered moderate sedation, to identify factors influencing the insertion, and the total procedural time.

Material and methods

A total of 47 insertions with hybrid intracavitary and interstitial applicators were performed in 23 patients from March 2017 to March 2020. Moderate sedation was achieved with intravenous midazolam and fentanyl administered by non-anesthetist. Insertion time and procedural time was recorded. Univariate and multivariate analysis were performed to evaluate the impact of different factors on insertion and procedural time.

Results

A total of 238 needles (range, 2-8 per insertion) were implanted, with an average insertion depth of 30 mm (range, 20-40 mm). The mean doses for midazolam and fentanyl were 3 mg (standard deviation [SD] = 1) and 53.3 mcg (SD = 23.9) per insertion, respectively. The median insertion time was 30 minutes (interquartile range [IQR] = 22-40), and the median total procedural time was 4.3 hours (IQR = 3.6-5.2). First time insertion, insertions performed before 2019, and higher midazolam dose were associated with significantly longer insertion time, whereas longer insertion time, MRI-based planning, and insertions performed before 2019 were associated with significantly longer total procedural time.

Conclusions

Outpatient interstitial brachytherapy with non-anesthetist-administered sedation is achievable and well-tolerated. This method may significantly lessen the burden on hospital resources and has the potential to be cost-effective.

Dosimetric and clinical outcomes of CT based HR-CTV delineation for HDR intracavitary brachytherapy in carcinoma cervix - a retrospective study

Background

Brachytherapy for carcinoma cervix has moved from Point A based planning to optimization of dose based on HR-CTV. Guidelines have been published by GEC ESTRO on HR-CTV delineation based on clinical gynecological examination and MR sequences. These have given significant clinical results in terms of local control. However, many centers around the country and worldwide still use CT based planning, which restricts HR-CTV delineation, as disease and cervix can rarely be differentiated on a planning CT. Various studies have been done to develop CT based contouring guidelines from the available data, but enough evidence is not available on the clinical outcome when treatment is optimized to HR-CTV contoured on CT images. The purpose of this study is to find out the relation between local control and dosimetry of HR-CTV as delineated on CT images.

Materials and methods

Patients of locally advanced carcinoma cervix treated radically with EBRT of 50 Gy in 25# and at least 4 cycles of concurrent weekly Cisplatin having a complete or partial response to EBRT were taken for study. All patients had completed CT based Intracavitary brachytherapy to 21 Gy in 3# of 7 Gy per # with dose prescription at point A and optimizing dose to reduce bladder and rectal toxicity. Follow up data on locoregional recurrence was obtained. HR-CTV delineation was done retrospectively on the treatment plan following guidelines by Viswanathan et al. EQD2 doses for EBRT+BT were calculated for point A and HR-CTV D90. The dosimetric data to HR-CTV and to Point A were then compared with patients with locoregional control and with local recurrence.

Results

48 patients were taken, all had squamous cell carcinoma. The median age was 48 years. 33.33% were stage IIA, the rest were stage IIB. Median follow-up was 30 months with 25% developing recurrence of the disease. HR-CTV D90 EQD2 dose was significantly higher in patients with locoregionally controlled disease than in patients with local recurrence (83.97 Gy₁₀ vs. 77.96 Gy₁₀, p = 0.002). Patients with HR-CTV D90 EQD2 dose greater than or equal to 79.75 Gy 10 had better locoregional control than patients receiving dose less than 79.75 Gy₁₀ (p = 0.015). Kaplan Meier plot for PFS showed significantly improved PFS for patients receiving HR-CTV D90 dose of at least 79.75 Gy₁₀ (log-rank p-value = 0.007). Three year progression free survival was 87.1% in patients receiving HR-CTV D90 dose of at least 79.75 Gy₁₀.

Conclusion

CT based HR-CTV volume delineation with the help of pre brachytherapy clinical diagrams and MRI imaging may be feasible in a select subgroup of patients with complete or near-complete response to external beam radiation.

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.

Comparison of clinical outcomes achieved with image-guided adaptive brachytherapy for cervix cancer using CT or transabdominal ultrasound

PURPOSE

This study aimed to evaluate retrospectively the treatment results when using various image-guided adaptive brachytherapy treatments for cervical cancer treated by radical radiotherapy.

METHODS AND MATERIALS

From 2014 to 2017, 188 patients with cervical carcinoma were treated by whole pelvic radiotherapy plus four fractions of image-guided brachytherapy. Eight patients were excluded because of missing data. Consequently, 180 patients were analyzed. Of 180 patients, 92 were treated by CT-based brachytherapy (CT-BT), and transabdominal ultrasound-based brachytherapy (TAUS-BT) was used to treat another group. The treatment results and toxicity outcomes were evaluated by comparing the image-guidance techniques.

RESULTS

The mean follow-up time was 32 months (interquartile range 29.5-42 months). The mean age was 57 years (interquartile range from 50 to 65 years). In the CT-BT group, the mean cumulative doses to high-risk clinical target volume, bladder, rectum, and sigmoid were 87.2 Gy, 84.0 Gy, 68.8 Gy, and 69.8 Gy, respectively. In the TAUS-BT group, the mean cumulative doses to the cervix reference, bladder, and rectum points were 84.0 Gy, 65.5 Gy, and 74.0 Gy, respectively. There were no differences in the 2-year local control rate (p = 0.88) and disease-free survival rate (p = 0.34) in both groups. No difference in gastrointestinal and genitourinary toxicity was observed in both groups, but there was higher vaginal toxicity in the TAUS-BT group compared with the CT-BT group (p = 0.03).

CONCLUSIONS

No difference in treatment results was observed between CT-based and TAUS-based approaches. However, TAUS-BT had higher vaginal toxicity in our retrospective analysis.

Association between cancer immunity and treatment results in uterine cervical cancer patients treated with radiotherapy

OBJECTIVE

To evaluate proteins related to tumor immune response and treatment outcome from radiotherapy for uterine cervical cancer patients.

METHODS

We performed a retrospective immunohistochemical staining of 81 patients with uterine cervical cancer who underwent definitive radiotherapy. We examined the expression of programmed death ligand 1, human leukocyte antigen class I, tumor-infiltrating CD8+, and forkhead box P3+ (FoxP3+) T cells in tumor tissues.

RESULTS

In biopsy specimen, patients with a higher number of CD8+ T cells and FoxP3+ T cells had a better disease-specific survival than patients with a lower number of CD8+ T cells and FoxP3+ cells (P = 0.018 and P = 0.009). Multivariate analysis showed that equivalent dose in 2 Gy fractions (EQD2) of the minimum dose to 90% of the high-risk clinical target volume, FoxP3+ T cells and expression of human leukocyte antigen class I were significant prognostic factors. When the EQD2 is 70 Gy or more, a higher local control rate is obtained regardless of the number of CD8- or FoxP3-positive cells. When EQD2 is <70 Gy, the number of CD8-positive cells has a significant impact on treatment outcome: the recurrence rate (local recurrence rate + distant metastasis rate) was 46.2% in the group with a CD8 value of 230 or higher, whereas the recurrence rate was 75.7% in the group with a CD8 value of less than 230.

CONCLUSION

The combination of CD8 or FoxP3 with EQD2 can be potentially useful to predict the treatment results of radiotherapy for cervical cancer, leading to individualized optimal selection of treatment for cervical cancer.

Configuration analysis of the injection position and shape of the gel spacer in gynecologic brachytherapy

PURPOSE

In this single-institution retrospective study, configuration analysis was performed to determine the optimal location and volume of hyaluronic acid gel spacer injection into the rectovaginal or vesicovaginal septum for effective dose reduction (DR) to the organs at risk (OARs), the rectum and bladder.

METHODS AND MATERIALS

70 and 50 intracavitary brachytherapy treatment plans used only vaginal cylinders with gel spacers for the rectal and bladder sides, respectively, whereas 28 did not use spacers. Correlation analysis was performed between the geometrical parameters and injection position of the gel spacers and the 2-cm³ covering doses of the OARs for each treatment.

RESULTS

A higher DR was predicted for hyaluronic acid gel spacer injection within ±5 mm and ±2.5 mm in the lateral-medial direction from the midpoint on the rectal and bladder sides, and ±10 mm in the cranial-caudal direction from the midpoint on the rectal side. There were correlations between 2-cm³ covering doses and the gel spacer parameters: the volume on the rectal (p = 0.02) and bladder (p = 0.04) sides; the craniocaudal length on the rectal side (p << 0.05); and ventrodorsad thickness on each OAR (p << 0.05) sides. There was no significant difference in the DR between a volume of ∼10 cm³ and that of a higher volume (p >> 0.05).

CONCLUSIONS

A gel spacer volume of ∼10 cm³ provides sufficient OAR DR if its gravity point is on the midpoint between the cylinder applicator and OAR, and its craniocaudal length covers the active length of the cylinder applicator.

Modern development of high-dose-rate brachytherapy

Brachytherapy is an invasive therapy with placement of radiation source into or near the tumor. The difference between planning target volume and clinical target volume is minimal, and the dose out of the tumor reduces rapidly due to the inverse-square law. High-dose-rate brachytherapy enables three-dimensional image guidance, and currently, tumor dose as well as doses of the surrounding normal structures can be evaluated accurately. High-dose-rate brachytherapy is the utmost precision radiation therapy even surpassing carbon ion therapy. Biological disadvantages of high-dose rate have been overcome by the fractional irradiation. High-dose-rate brachytherapy is indispensable in the definitive radiation therapy of cervical cancer. Also in prostate cancer and breast cancer, high-dose-rate brachytherapy plays a significant role. Brachytherapy requires techniques and skills of radiation oncologists at the time of invasive placement of the radiation source into the tumor area. Education of young radiation oncologists is most urgent and important.

Preliminary survey of 3D image-guided brachytherapy for cervical cancer at representative hospitals in Asian countries

3D image-guided brachytherapy (3D-IGBT) has become a standard therapy for cervical cancer. However, the use of 3D-IGBT is limited in East and Southeast Asia. This study aimed to clarify the current usage patterns of 3D-IGBT for cervical cancer in East and Southeast Asia. A questionnaire-based survey was performed in 11 countries within the framework of the Forum for Nuclear Cooperation in Asia. The questionnaire collected the treatment information of patients with cervical cancer who underwent 3D-IGBT. The cumulative external beam radiotherapy and 3D-IGBT doses were summarized and normalized to a biological equivalent dose of 2 Gy per fraction (EQD2) using a linear-quadratic model. Of the 11 institutions representing the participating countries, six (55%) responded to the questionnaire. Overall, data of 36 patients were collected from the six institutions. Twenty-one patients underwent whole-pelvic irradiation and 15 underwent whole-pelvic irradiation with central shielding. Patients received a median of four treatment sessions of 3D-IGBT (range, 2-6). All 3D-IGBT sessions were computed tomography (CT)-based and not magnetic resonance image-based. The median doses to the high-risk clinical target volume D90, bladder D2cc, rectum D2cc and sigmoid colon D2cc were 80.9 Gy EQD2 (range, 58.9-105.9), 77.7 Gy EQD2 (range, 56.9-99.1), 68.0 Gy EQD2 (range, 48.6-90.7) and 62.0 Gy EQD2 (range, 39.6-83.7), respectively. This study elucidated the current patterns of 3D-IGBT for the treatment of cervical cancer in East and Southeast Asia. The results indicate the feasibility of observational studies of CT-based 3D-IGBT for cervical cancer in these countries.

Dose-effect response in image-guided adaptive brachytherapy for cervical cancer: A systematic review and meta-regression analysis

PURPOSE

This study aimed to integrate and update the dose-effect relationship between volumetric dose and local control for cervical cancer brachytherapy.

METHODS AND MATERIALS

We identified studies that reported high-risk clinical target volume (HR-CTV) D₉₀ and local control probability by searching PubMed, Web of Science, and the Cochrane Library databases through Oct 27, 2019. The regression analyses were performed using a probit model between HR-CTV D₉₀, D₁₀₀, intermediate-risk clinical target volume (IR-CTV) D₉₀, and dose to Point A vs. local control probability. Subgroup analyses were performed according to stratification: time of local control, income level of the country or region, stage of cancer, pathology, mean volume of HR-CTV, dose rate, image modality, concurrent chemoradiotherapy proportion, interstitial proportion, and mean overall treatment time.

RESULTS

Thirty-three studies encompassing 2893 patients were included. The probit model showed a significant relationship between the HR-CTV D₉₀ value and the local control probability, p < 0.0001. The D₉₀ corresponding to a probability of 90% local control was 83.7 Gy_EQD2,10 (80.6-87.8 Gy_EQD2,10). Of the 33 studies included in our analysis, eight studies, including 1172 patients, reported the IR-CTV D₉₀ value, ranging from 59.1 Gy_EQD2,10 to 72.3 Gy_EQD2,10. The probit model also showed a significant relationship between the IR-CTV D₉₀ value and the local control probability, p = 0.0464. The 60 Gy_EQD2,10 for IR-CTV D₉₀ corresponded to an 86.1% local control probability (82.0%-89.8%).

CONCLUSIONS

A significant dependence of local control on HR-CTV D₉₀ and IR-CTV D₉₀ was found. A tumor control probability of >90% can be expected at doses >84 Gy_EQD2,10 and 69 Gy_EQD2,10, respectively, based on an updated meta-regression analysis.

Retrospective DVH analysis of point A based intracavitary brachytherapy for uterine cervical cancer

Combining external beam radiotherapy (EBRT) with intracavitary brachytherapy (ICBT) is important for definitive treatment of cervical cancer. In cervical cancer patients receiving radiotherapy, we evaluated treatment outcomes in relation to dose-volume histogram parameters, including the computed tomography (CT)-based high-risk clinical target volume (HR-CTV) for ICBT. Between 2010 and 2015, 89 consecutive cervical cancer patients were mostly treated with 40 Gy of EBRT in 20 fractions and 18 Gy of ICBT prescribed to point A in 3 fractions. CT scans were obtained during ICBT. The HR-CTV D90 was calculated and the total doses of ICBT and EBRT were converted to the equivalent dose in 2 Gy fractions (EQD2). When the patients were divided into four groups according to EQD2 of the HR-CTV D90, the 3-year local recurrence-free survival rates were 95.2, 78.4, 52.7 and 42.9% for patients receiving >80 , 70-80 , 60-70 and <60 Gy, respectively. There was a significant negative correlation between EQD2 of the HR-CTV D90 and the HR-CTV volume at first ICBT (r = -0.713). Local recurrence was more frequent when the HR-CTV volume was ≥22 cc and EQD2 of the HR-CTV D90 was <70 Gy. Multivariate analysis showed that EQD2 of the HR-CTV D90 and concurrent chemotherapy (≥4 cycles) were significant determinants of overall survival. HR-CTV D90 was an important prognostic indicator for local recurrence. HR-CTV D90 >70 Gy is required for the better local control, especially in patients with a larger HR-CTV (≥22 cc at initial ICBT).

Definitive radiotherapy consisting of whole pelvic radiotherapy with no central shielding and CT-based intracavitary brachytherapy for cervical cancer: feasibility, toxicity, and oncologic outcomes in Japanese patients

BACKGROUND

This prospective study investigated the feasibility, toxicity, and oncologic outcomes of definitive radiotherapy (RT) consisting of whole pelvic radiotherapy with no central shielding (noCS-WPRT) and CT-based intracavitary brachytherapy (ICBT) in Japanese patients with cervical cancer.

METHODS

Patients with cervical cancer of FIGO stages IB1-IVA were eligible. The treatment protocol consisted of noCS-WPRT of 45 Gy in 25 fractions and CT-based high dose-rate ICBT of 15 or 20 Gy in 3 or 4 fractions prescribed at point A. The prescribed ICBT dose was decreased if the manual dwell time/position optimization failed to meet organs-at-risk constraints. Graphical optimization and additional interstitial needles were not applied.

RESULTS

We enrolled 40 patients. FIGO stages were IB1: 11, IB2: 13, IIA2: 1, IIB: 11, IIIB: 3, and IVA: 1. Median (range) pretreatment tumor diameter was 47 (14-81) mm. Point A doses were decreased in 19 of 153 ICBT sessions (12%). The median follow-up duration was 33 months. The 2-year rates of pelvic control, local control (LC), and progression-free survival were 83%, 85%, and 75%, respectively. Pre-ICBT tumor diameter, high-risk clinical target volume (HR-CTV), total HR-CTV D90, and overall treatment time (OTT) significantly affected LC. Late adverse events (grade ≥ 3) were observed in 3 patients (2 in the bladder, 1 in the rectum).

CONCLUSIONS

Definitive RT consisting of noCS-WPRT and CT-based ICBT was feasible for Japanese patients with cervical cancer. To further improve LC, additional interstitial needles for patients with a large HR-CTV and shorter OTT should be considered.

Hyaluronic acid gel injection in rectovaginal septum reduced incidence of rectal bleeding in brachytherapy for gynecological malignancies

PURPOSE

The purpose of this study was to report our initial clinical results of hyaluronic acid gel injection (HGI) in the rectovaginal septum (RVS) to reduce the incidence of rectal bleeding in vaginal brachytherapy for gynecologic malignancies.

METHODS AND MATERIALS

Since 2008, CT based image-guided adaptive brachytherapy (IGABT) was initiated, and since 2015, HGI in the RVS was introduced in our institution. Vaginal cylinder with or without tandem or additional interstitial needles were applied for patients with gynecologic malignancies. Rectum dosimetric parameters and incidence of late rectum bleeding were compared between patients with and without HGI in the RVS.

RESULTS

Between May 2008 and October 2017, 83 patients with gynecologic malignancies were treated with IGABT involving vaginal cylinder. Eleven patients who were treated for palliative intention were excluded, and 72 patients were subjected to the analysis. Of the total 72 patients 46 were with uterine cervical cancer, 19 uterine corpus cancer, five vaginal cancer, one vulvar cancer, and one ovarian cancer. Fifteen and 57 patients were irradiated with and without HGI in the RVS, respectively. With a median follow-up period of 57.7 (4.7-123.1) months, 30 (41.7%) patients suffered from radiation-related rectal bleeding. Patients with HGI in the RVS had a statistically significant lower incidence of rectal bleeding compared with those without it (13.3% vs. 49.1%, p = 0.01).

CONCLUSIONS

HGI in the RVS reduced the incidence of late rectal bleeding for patients with gynecologic malignancies treated by vaginal cylinder and was not associated with HGI-procedure-related adverse events.

Impact of CT-based brachytherapy in elderly patients with cervical cancer

PURPOSE

Three-dimensional image-guided brachytherapy (3D-IGBT) has become the standard therapy for patients with cervical cancer. However, in this population, the impact of 3D-IGBT in elderly individuals remains unknown. This study assessed the efficacy of 3D-IGBT for elderly patients with cervical cancer.

METHODS AND MATERIALS

We performed a retrospective chart review of 105 consecutive patients with cervical squamous cell carcinoma aged ≥70 years who received radiotherapy alone between January 2001 and September 2014. All patients were treated with external beam radiotherapy and high-dose-rate intracavitary brachytherapy. We assessed the treatment outcomes in all patients. We then compared outcomes between two groups: patients treated by changing the Point A dose at brachytherapy (Group A, n = 71) and those treated with 3D-IGBT at least twice (Group B, n = 34).

RESULTS

The median followup period was 59 (range, 6-203) months; the median age was 77 years. The 5-year local control and cause-specific survival rates were 89% and 78%, respectively. The 5-year cumulative rates of late toxicities of the rectum and bladder of Grade ≥3 were 2.0% and 4.2%, respectively. No statistically significant differences were observed in the local control and cause-specific survival rates, or in the incidence of rectal toxicities between groups. The 3-year cumulative rates of urinary toxicity of Grade ≥1 were 20.4% and 6.9% in Group A and Group B, respectively (p = 0.035).

CONCLUSION

In elderly patients with cervical cancer, 3D-IGBT could be performed safely and effectively and contributed to decreasing urinary toxicity incidence rates.

Dose-volume parameters and local tumor control in cervical cancer treated with central-shielding external-beam radiotherapy and CT-based image-guided brachytherapy

Definitive radiotherapy for cervical cancer consists of external-beam radiotherapy (EBRT) and brachytherapy. In EBRT, a central shield (CS) reduces the dose to the rectum and bladder. The combination of whole-pelvic (WP)- and CS-EBRT and brachytherapy is the standard radiotherapy protocol in Japan. Despite clinical studies, including multi-institutional clinical trials, showing that the Japanese treatment protocol yields favorable treatment outcomes with low rates of late radiation toxicities, dose-volume parameters for the Japanese treatment protocol remain to be established. We conducted a retrospective dose-volume analysis of 103 patients with uterine cervical cancer treated with the Japanese protocol using computed tomography-based adaptive brachytherapy. The 2-year overall survival and 2-year local control rates according to FIGO stage were 100% and 100% for Stage I, 92% and 94% for Stage II, and 85% and 87% for Stage III-IV, respectively. Late adverse effects in the rectum and bladder were acceptable. Receiver operating characteristic analysis discriminated recurrence within the high-risk clinical target volume (HR-CTV) (n = 5) from no local recurrence (n = 96), with the optimal response obtained at a dose of 36.0 GyEQD2 for HR-CTV D90 and 28.0 GyEQD2 for HR-CTV D98. These values were used as cut-offs in Fisher exact tests to show that high HR-CTV D90 and HR-CTV D98 doses for brachytherapy sessions were significantly associated with tumor control within the HR-CTV. These data suggest a contribution of brachytherapy to local tumor control in WP- and CS-EBRT and brachytherapy combination treatment, warranting validation in multi-institutional prospective studies.

Global Collaborations for Cervical Cancer: Can the East-West Alliance Facilitate Treatment for all?

Despite the advances in the primary prevention of cervical cancer, there is an absolute increase in the incidence of cervical cancer as a result of an increase in world population. A vast majority of patients in low and low-middle income countries continue to present at a locally advanced stage, necessitating treatment with chemoradiation and brachytherapy. There is a dearth of equipment and trained professionals for the treatment of cervical cancer, especially in low and low-middle income countries. There is an urgent need to improve treatment availability and develop better treatments. Worldwide trends, however, reveal a low number of therapeutic and innovative research trials in cervical cancer. The present article elucidates the existing challenges and provides solutions to improve outcomes. The proposed strategies hinge on strengthening collaborations for global advocacy.

Impact of different dose prescription schedules on EQD2 in high-dose-rate intracavitary brachytherapy of carcinoma cervix

PURPOSE

To observe the effect of different high-dose-rate (HDR) intracavitary brachytherapy dose schedules on equieffective dose in 2 Gy per fraction (EQD2).

MATERIAL AND METHODS

It is a retrospective study involving 50 cervical cancer patients, who received external radiotherapy of 45 Gy in 25 fractions and underwent intracavitary brachytherapy (ICBT). Computed tomography (CT) simulation was done after insertion of the applicators. High-risk clinical target volume (CTVHR) and organs at risk (OARs) such as bladder, rectum, and sigmoid were contoured. Four different plans were generated for each patient, with dose prescriptions of 5.5 Gy × 5 fractions (plan A), 6.5 Gy × 4 fractions (plan B), 7 Gy × 4 fractions (plan C), and 9 Gy × 2 fractions (plan D), delivered to CTVHR. The total EQD2 for 0.1 cm3 and 2 cm3 of bladder, rectum, and sigmoid as well as dose received by 90% of the CTVHR (D90) and point A were calculated. The values were analyzed and compared with available literature.

RESULTS

The mean CTVHR volume was 47.12 ±13.8 cm3. All plans delivered similar EQD2 for 0.1 cm3 and 2 cm3 of sigmoid. Plan D delivered lesser EQD2 compared to other plans for bladder, rectum, D90 CTVHR, and point A (p = 0.0001). Plan C delivered higher EQD2 to OARs compared to other plans (p = 0.001). Plan A, B, and plan C delivered similar EQD2 for D90 CTVHR and point A.

CONCLUSIONS

EQD2 of bladder, rectum, sigmoid, D90 CTVHR, and point A were similar with 5.5 Gy × 5 fractions, 6.5 Gy × 4 fractions, and 7 Gy × 4 fractions, whereas EQD2 of 9 Gy × 2 fractions was significantly unfavorable compared to other schedules. Further clinical studies are recommended to observe clinical outcomes.

A hybrid technique of intracavitary and interstitial brachytherapy for locally advanced cervical cancer: initial outcomes of a single-institute experience

BACKGROUND

Locally advanced uterine cervical cancer (LAUCC) with lateral tumor extension may not always be covered adequately by conventional intracavitary brachytherapy (ICBT). Hybrid intracavitary and interstitial brachytherapy (HBT) seems to be an effective alternative by improving anatomy-oriented dose optimisation. The purpose of this study was to report initial clinical result for LAUCC treated by HBT.

METHODS

Between January 2012 and November 2015, 42 patients with LAUCC (T1b2-4a) were treated with primary radiation therapy including HBT. Patients with distant metastasis other than para-aortic lymph node spread were excluded from this study. A retrospective analysis was performed for toxicity evaluation and oncological outcome calculation.

RESULTS

Median follow-up was 23.2 months (range 13.2-71.4). Two-year overall survival, progression free survival, and local control rate were 81.6, 54.4, and 80.2%, respectively. Seven patients experienced local recurrence (16.6%). Of those, five were confined to the uterus and two at the parametria. Late adverse events ≥ grade 3 were seen in 3 patients.

CONCLUSIONS

HBT can generate favorable local control in tumors which cannot be adequately covered by ICBT.

A 3-year follow-up study of radiotherapy using computed tomography-based image-guided brachytherapy for cervical cancer

Outcomes for patients with Stage IB1-IVA cervical cancer treated with computed tomography (CT)-based image-guided brachytherapy (IGBT) were examined in this study. A total of 84 patients were analyzed between March 2012 and June 2015. Whole-pelvic radiotherapy with a central shield was performed for each patient, and the total pelvic sidewall dose was 50 Gy. IGBT was delivered in 2-4 fractions. The initial prescription dose (6.8 Gy) was delivered at Point A, and the dose distribution was modified manually by graphical optimization. The total dose was calculated as the biologically equivalent dose in 2 Gy fractions (EQD2). Concurrent chemotherapy was administered to 64 patients (76%). The median follow-up period was 36 months (range 2-62 months). The 3-year overall survival, local control, and progression-free survival rates were 94%, 89% and 81%, respectively. The mean EQD2 for HR-CTV D90 was 73.4 Gy, and the EQD2 for HR-CTV D90 was not significantly associated with the local control rate. In multivariate analysis, adenocarcinoma (P = 0.03) and tumor size ≥45 mm (P = 0.06) were risk factors for local control. The patients were divided into four groups based on histology (squamous cell carcinoma vs adenocarcinoma) and tumor size (<45 vs ≥45 mm). Those with large adenocarcinomas had significantly worse outcomes. In conclusion, CT-based IGBT achieved favorable local control, but different treatment strategies may be necessary for large adenocarcinomas.

Hyaluronic gel injection into the vesicovaginal septum for high-dose-rate brachytherapy of uterine cervical cancer: an effective approach for bladder dose reduction

Purpose

The purpose of this study was to report our initial experience of hyaluronic acid gel injection (HGI) in the vesicovaginal septum (VVS) for bladder dose reduction in brachytherapy (BT) for uterine cervical carcinoma.

Material and methods

Between September 2016 and May 2018, 15 uterine cervical cancer patients received HGI in the VVS as a part of their definitive radiotherapy (RT) treatment consisting of external beam radiation therapy (EBRT) with additional BT. Of those, 9 patients received BT both with and without HGI, and remaining 6 patients were excluded because these 6 patients received HGI in the VVS for all BT fractions. All 9 patients received HGI in the rectovaginal septum. For these patients, the dosimetric parameters bladder D_2cc, HR-CTV D₉₀, and rectum D_2cc were selected, and two groups were generated (BT with vs. without HGI in the VVS) for dosimetric comparison.

Results

The median cumulative EQD₂ for HR-CTV, rectum D_2cc, and bladder D_2cc for the 9 patients were 73.3, 52.8, and 67.1, respectively. While no statistical difference could be detected for rectal dose reduction, bladder dose was significantly less in the group with HGI in the VVS compared to that without (449 cGy [range, 416-566, 1SD = 66.1] vs. 569 cGy [range, 449-647, 1SD = 59.5], p = 0.033), with no compromising of target coverage. Although it did not reach statistically significance, there was a trend toward better HR-CTV D₉₀ in the group with HGI compared to that without HGI in the VVS (713 cGy vs. 706 cGy, p = 0.085). No severe bleeding, hematuria, bladder wall injury, or urethral injury requiring hospitalization was experienced in association with HGI in the VVS.

Conclusions

HGI in the VVS can be performed safely and can effectively reduce the bladder dose in BT for uterine cervical cancer patients.

Dose constraints in the rectum and bladder following carbon-ion radiotherapy for uterus carcinoma: a retrospective pooled analysis

Background

Carbon-ion radiotherapy (C-ion RT) provides better dose distribution in cancer treatment compared to photons. Additionally, carbon-ion beams provide a higher biological effectiveness, and thus a higher tumor control probability. However, information regarding the dose constraints for organs at risk in C-ion RT is limited. This study aimed to determine the predictive factors for late morbidities in the rectum and bladder after carbon-ion C-ion RT for uterus carcinomas.

Methods

Between June 1995 and January 2010, 134 patients with uterus carcinomas were treated with C-ion RT with curative intent; prescription doses of 52.8–74.4 Gy (relative biological effectiveness) were delivered in 20–24 fractions. Of these patients, 132 who were followed up for > 6 months were analyzed. We separated the data in two subgroups, a 24 fractions group and a 20 fractions group. Late morbidities, proctitis, and cystitis were assessed according to the Radiation Therapy Oncology Group/European Organisation for Research and Treatment of Cancer criteria. The correlations of clinical and dosimetric parameters, V10–V60, D_5cc, D_2cc, and Dmax, with the incidence of ≥grade 1 morbidities were retrospectively analyzed.

Results

In the 24 fractions group, the 3-year actuarial occurrence rates of ≥grade 1 rectal and bladder morbidities were 64 and 9%, respectively. In addition, in the 20 fractions group, the 3-year actuarial occurrence rates of ≥grade 1 rectal and bladder morbidities were 32 and 19%, respectively. Regarding the dose–volume histogram data on the rectum, the D_5cc and D_2cc were significantly higher in patients with ≥grade 1 proctitis than in those without morbidity. In addition, the D_5cc for the bladder was significantly higher in patients with ≥grade 1 cystitis than in those without morbidity. Results of univariate analyses showed that D_2cc of the rectum was correlated with the development of ≥grade 1 late proctitis. Moreover, D_5cc of the bladder was correlated with the development of ≥grade 1 late cystitis.

Conclusions

The present study identified the dose–volume relationships in C-ion RT regarding the occurrence of late morbidities in the rectum and bladder. Assessment of the factors discussed herein would be beneficial in preventing late morbidities after C-ion RT for pelvic malignancies.

Trial registration

Retrospectively registered (NIRS: 16–040).

Electronic supplementary material

The online version of this article (10.1186/s13014-018-1061-7) contains supplementary material, which is available to authorized users.

Computed tomography-based image-guided brachytherapy for cervical cancer: correlations between dose-volume parameters and clinical outcomes

This study evaluated the oncologic outcomes and complications of cervical cancer patients in terms of CT-based image-guided brachytherapy (IGBT) parameters. Of 68 cervical cancer patients treated with definitive radiotherapy/concurrent chemoradiotherapy, most received whole-pelvis external beam RT (EBRT) of 40 Gy in 20 fractions, pelvic EBRT with central shield of 10 Gy in 5 fractions, and CT-based IGBT of 18 Gy in 3 fractions prescribed to point A. Cumulative EBRT and IGBT doses were calculated as the total equivalent dose in 2 Gy fractions (EQD2). The median follow-up was 31 (3-52) months. The 2-year overall survival, local control, pelvic control, and disease-free survival rates of the 68 patients were 92%, 83%, 82% and 73%, respectively. The HR-CTV D90, length from the tandem axis to left/right margin of the HR-CTV (T-LR), and HR-CTV volume were significant IGBT parameters for predicting local/pelvic control. Patients who received an HR-CTV D90 of >60 Gy, compared with ≤60 Gy, had significantly better local/pelvic control. Furthermore, 70 Gy was a marginally significant HR-CTV D90 cut-off affecting local control. T-LR was an independent IGBT parameter predicting local/pelvic control on multivariate analysis. Three patients developed Grade 3 or higher treatment-related complications. The D2cm3 of organs at risk were not significant predictors of complications. Future challenges for further improving outcomes include additional interstitial needles for irregularly shaped HR-CTVs, and moderate dose escalation, especially for patients with poor tumor responses.

In-room computed tomography-based brachytherapy for uterine cervical cancer: results of a 5-year retrospective study

Herein, we investigate the long-term clinical outcomes for cervical cancer patients treated with in-room computed tomography-based brachytherapy. Eighty patients with Stage IB1-IVA cervical cancer, who had undergone treatment with combined 3D high-dose rate brachytherapy and conformal radiotherapy between October 2008 and May 2011, were retrospectively analyzed. External beam radiotherapy (50 Gy) with central shielding after 20-40 Gy was performed for each patient. Cisplatin-based chemotherapy was administered concurrently to advanced-stage patients aged ≤75 years. Brachytherapy was delivered in four fractions of 6 Gy per week. In-room computed tomography imaging with applicator insertion was performed for treatment planning. Information from physical examinations at diagnosis, and brachytherapy and magnetic resonance imaging at diagnosis and just before the first brachytherapy session, were referred to for contouring of the high-risk clinical target volume. The median follow-up duration was 60 months. The 5-year local control, pelvic progression-free survival and overall survival rates were 94%, 90% and 86%, respectively. No significant differences in 5-year local control rates were observed between Stage I, Stage II and Stage III-IVA patients. Conversely, a significant difference in the 5-year overall survival rate was observed between Stage II and III-IVA patients (97% vs 72%; P = 0.006). One patient developed Grade 3 late bladder toxicity. No other Grade 3 or higher late toxicities were reported in the rectum or bladder. In conclusion, excellent local control rates were achieved with minimal late toxicities in the rectum or bladder, irrespective of clinical stage.

Recommendations for high-risk clinical target volume definition with computed tomography for three-dimensional image-guided brachytherapy in cervical cancer patients

Our purpose was to develop recommendations for contouring the computed tomography (CT)-based high-risk clinical target volume (CTVHR) for 3D image-guided brachytherapy (3D-IGBT) for cervical cancer. A 15-member Japanese Radiation Oncology Study Group (JROSG) committee with expertise in gynecological radiation oncology initiated guideline development for CT-based CTVHR (based on a comprehensive literature review as well as clinical experience) in July 2014. Extensive discussions occurred during four face-to-face meetings and frequent email communication until a consensus was reached. The CT-based CTVHR boundaries were defined by each anatomical plane (cranial-caudal, lateral, or anterior-posterior) with or without tumor progression beyond the uterine cervix at diagnosis. Since the availability of magnetic resonance imaging (MRI) with applicator insertion for 3D planning is currently limited, T2-weighted MRI obtained at diagnosis and just before brachytherapy without applicator insertion was used as a reference for accurately estimating the tumor size and topography. Furthermore, utilizing information from clinical examinations performed both at diagnosis and brachytherapy is strongly recommended. In conclusion, these recommendations will serve as a brachytherapy protocol to be used at institutions with limited availability of MRI for 3D treatment planning.

Outcomes with volume-based dose specification in CT-planned high-dose-rate brachytherapy for stage I-II cervical carcinoma: A 10-year institutional experience

OBJECTIVE

To determine prognostic factors for progression-free survival (PFS) and overall survival (OS) for stage I-II cervical-cancer patients treated using computed-tomography (CT)-planned high-dose-rate (HDR) intracavitary brachytherapy (BT).

METHODS

A total of 150 patients were treated for Stage I-II cervical cancer using CT-planned BT between 4/2004 and 10/2014. Of these, 128 were eligible for inclusion. Kaplan-Meier local control (LC), pelvic control (PC), overall survival (OS), and PFS estimates were calculated.

RESULTS

After a median follow-up of 30months, the 2-year LC rate was 96%, PFS was 88%, and OS was 88%. Overall, 18 patients (14%) experienced any recurrence (AR), 8 had distant recurrence only and 10 had a combination of local, pelvic, regional, and distant recurrence. No patients had LR only. A prognostic factor for AR was tumor size >4cm (p=0.01). Patients with tumors >4cm were 3.3 times more likely to have AR than those with tumors ≤4cm (hazard ratio [HR]=3.3; 95% confidence interval [CI] 1.28-9.47). Point A was 85% of prescription for tumors < 4 cm and decreased approximately 3% over 5 fractions compared to 90% of prescription for tumors > 4 cm that decreased approximately 4% over 5 fractions. Two patients (2%) experienced grade≥2 late toxicity. There were no acute or late grade≥3 toxicities.

CONCLUSION

CT-planned BT resulted in excellent local control and survival. Large tumor size was associated with an increased risk of recurrence outside the radiation field and worse PFS and OS. A volume-optimized plan treated a smaller area than a point A standard plan for patients with Stage I-II cervical cancer that have received chemoradiation. Given the outstanding LC achieved with modern therapy including chemoradiation, HDR, and image-based BT, further efforts to combat spread outside the radiation field with novel therapies are warranted.

The role of interstitial brachytherapy in the management of primary radiation therapy for uterine cervical cancer

Purpose

The aim of this study was to report the clinical results of uterine cervical cancer patients treated by primary radiation therapy including brachytherapy, and investigate the role of interstitial brachytherapy (ISBT).

Material and methods

All consecutive uterine cervical cancer patients who were treated by primary radiation therapy were reviewed, and those who were treated by ISBT were further investigated for clinical outcomes and related toxicities.

Results

From December 2008 to October 2014, 209 consecutive uterine cervical cancer patients were treated with primary radiation therapy. Among them, 142 and 42 patients were treated by intracavitary and hybrid brachytherapy, respectively. Twenty-five patients (12%) were treated by high-dose-rate (HDR)-ISBT. Five patients with distant metastasis other than para-aortic lymph node were excluded, and 20 patients consisted of the analysis. Three-year overall survival (OS), progression-free survival (PFS), and local control (LC) rate were 44.4%, 38.9%, and 87.8%, respectively. Distant metastasis was the most frequent site of first relapse after HDR-ISBT. One and four patients experienced grade 3 and 2 rectal bleeding, one grade 2 cystitis, and two grade 2 vaginal ulcer.

Conclusions

Feasibility and favorable local control of interstitial brachytherapy for locally advanced cervical cancer was demonstrated through a single institutional experience with a small number of patients.

A phase I/II clinical trial for the hybrid of intracavitary and interstitial brachytherapy for locally advanced cervical cancer

Background

This paper describes about a study protocol of phase I/II multicenter prospective clinical trial evaluating the feasibility and efficacy of the hybrid of intracavitary and interstitial brachytherapy (HBT) for locally advanced uterine cervical cancer patients.

Methods and design

Patients with histologically confirmed FIGO stage IB2, IIA2, IIB, and IIIB uterine cervical carcinoma width of which is larger than 5 cm assessed by MRI will be entered to this clinical trial. Protocol therapy is 30-30.6 Gy in 15-17 fractions of whole pelvic radiotherapy concurrent with weekly CDDP (40 mg/m²), followed by 24 Gy in 4 fractions of HBT and central shield EBRT up to 50-50.4 Gy in 25-28 fractions. Tumor width is assessed again within one week before the first HBT and if the tumor width is larger than 4 cm, patients proceed to the secondary registration. In phase I section, feasibility of this will be investigated. If less than 10 % out of 20 patients experienced greater than grade 3 acute non-hematologic adverse effects, the study proceeds to phase II part. In phase II part a total of 55 patients will be accrued and the efficacy of the HBT will be investigated comparing with historical control data. If the lower margin of 90 % confidence interval of the 2-year pelvic progression-free survival of the HBT trial is higher than 64 %, the HBT is considered to be more effective than conventional ICBT.

Discussion

The aim of this study is to demonstrate the feasibility and efficacy of the HBT for locally advanced cervical cancer. This trial will clarify the indication, feasibility, and efficacy of this new technique.

Trial registration

UMIN000019081; Registration date: 2015/9/30

Dose-volume histogram analysis of composite EQD2 dose distributions using the central shielding technique in cervical cancer radiotherapy

PURPOSE

To analyze the dose-volume histogram of the central shielding technique for cervical cancer radiotherapy by computing the composite three-dimensional EQD2 dose distributions of external-beam radiotherapy plus intracavitary brachytherapy.

METHODS AND MATERIALS

On a phantom, three patterns of high-risk clinical target volume (HR-CTV) with right-left diameters of 3, 4, and 5 cm were created using clinical data. Four patterns of combinations of whole-pelvis irradiation plus "pelvis irradiation using the central shielding technique" (CS) (shielding width, 3 or 4 cm) were created: 20 Gy/10 fractions + 30 Gy/15 fractions, 30 Gy/15 fractions + 20 Gy/10 fractions, 40 Gy/20 fractions + 10 Gy/5 fractions, and 50 Gy/25 fractions + 0 Gy. The intracavitary brachytherapy plan was set as 24 Gy/4 fractions prescribed to the Point A. The HR-CTV D90/D98 and modeled bladder/rectum D2cc were computed using the composite EQD2 dose distributions of all the treatment combinations.

RESULTS

If appropriate combinations of the treatment plans were selected on the basis of the CS doses and the HR-CTV sizes, the D90/D98 of HR-CTV 3 cm, HR-CTV 4 cm, and HR-CTV 5 cm were 89.7 Gy/80.6 Gy, 77.3 Gy/72.0 Gy, and 73.0 Gy/69.2 Gy in the case of CS width 3 cm, respectively; and 86.2 Gy/76.0 Gy, 73.3 Gy/67.6 Gy, and 70.9 Gy/67.1 Gy in the case of CS width 4 cm, respectively. The contributions of CS to the HR-CTV D90/bladder D2cc/rectum D2cc values were 24-56%/28-32%/9% of the CS plan doses for shielding width of 3 cm and were 13-35%/11-16%/5-6% for shielding width of 4 cm.

CONCLUSION

The dose contributions of CS were variable but not negligible when analyzing the total doses delivered to the HR-CTV.

Phase II study of concurrent chemoradiotherapy with weekly cisplatin and paclitaxel in patients with locally advanced uterine cervical cancer: The JACCRO GY-01 trial

OBJECTIVE

A multicenter phase II trial was conducted to assess the efficacy and toxicity of concurrent chemoradiotherapy (CCRT) with weekly cisplatin (CDDP) and paclitaxel (PTX) in patients with locally advanced uterine cervical cancer.

METHODS

Patients with FIGO stage III-IVA uterine cervical cancer without para-aortic lymphadenopathy were enrolled. Patients received definitive radiotherapy (RT) consisting of external beam whole-pelvic RT and high-dose-rate intracavitary brachytherapy. The cumulative linear quadratic equivalent dose was 62-65Gy prescribed at point A. weekly CDDP at 30mg/m(2) and PTX at 50mg/m(2) were administered concurrently with RT for ≥5 courses.

RESULTS

Sixty-eight of the 70 registered patients were eligible. The complete response rate was 76.5% (95% confidence interval [CI], 66.4-86.6%). With a median follow-up of 27months (range, 7.9-33.5), the 2-year cumulative progression-free survival and the 2-year cumulative overall survival rates were 83.8% (95% CI, 75.1-92.6%) and 92.7% (95% CI, 86.4-98.9%), respectively. The pelvic cumulative disease progression-free and the 2-year cumulative distant metastasis rates were 89.6% (95% CI, 82.3-96.9%) and 13.2% (95% CI, 5.2-21.3%), respectively. The 2-year cumulative late complication rates were 25% for all grades, 13.2% for grade 1, 5.9% for grade 2, 2.9% for grade 3, and 2.9% for grade 4.

CONCLUSIONS

For locally advanced cervical cancer, CCRT with weekly CDDP 30mg/m(2) and PTX at 50mg/m(2) demonstrated favorable antitumor activity, and was feasible and safe with respect to the protocol-specified serious adverse reactions and events. Evaluation of this regimen in phase III trials is warranted.