American Brachytherapy Society recurrent carcinoma of the endometrium task force patterns of care and review of the literature

Design approach and benefits of the 3D-printed vaginal individualized applicator (VIA)

PURPOSE

Interstitial gynecologic brachytherapy necessitates precise needle placement, requiring time and expertise. We aimed to simplify interstitial procedures and facilitate optimal needle distribution with individualized vaginal templates to guide interstitial needles.

MATERIALS/METHODS

We developed the 3D-printed vaginal individualized applicator (VIA), a cylindrical template containing individualized internal channels that guide interstitial needles to cover the tumor extent. Eight patients underwent VIA only interstitial implants (VIA only), and five intact cervical cases were treated using tandem and customized VIA (VIA + T). Procedure length, number of needles utilized and dosimetric measures were evaluated.

RESULTS

VIA was successfully designed and used clinically for 24 procedures (8 VIA only, 16 VIA + T). Average procedure needle insertion time reduced from 80.9 min for traditional interstitial to 42.9 min for VIA only, approximately 47% shorter with a similar mean high risk CTV volume (28.3 cc VIA only vs. 32.4 cc) and excellent dosimetry with average CTV V100% (94.3% and 94.4%). VIA + T was particularly useful in patients with small vaginal canals and large tumor size. For the five VIA + T patients average tumor size was 68.0cc (range 26.6-143.5 cc). VIA + T procedures were approximately 20% shorter than hybrid procedures with other applicators with mean length of 20.1 min and an average of 6.8 needles (range 3-12).

CONCLUSION

Our novel 3D-printed VIA facilitates gynecologic interstitial brachytherapy by simplifying needle placement, reducing procedure time, and maintaining excellent dosimetry. VIA can be customized for various clinical scenarios, particularly beneficial for large tumors or small vaginal canals.

Radiation Therapy With or Without Cisplatin for Local Recurrences of Endometrial Cancer: Results From an NRG Oncology/GOG Prospective Randomized Multicenter Clinical Trial

PURPOSE

Pelvic recurrence is a frequent pattern of relapse for women with endometrial cancer. A randomized trial compared progression-free survival (PFS) after treatment with radiation therapy alone as compared with concurrent chemotherapy.

MATERIALS AND METHODS

Between February 2008 and August 2020, 165 patients were randomly assigned 1:1 to receive either radiation treatment alone or a combination of chemotherapy and radiation treatment. The primary objective of this study was to determine whether chemoradiation therapy was more effective than radiation therapy alone at improving PFS.

RESULTS

The majority of patients had low-grade (1 or 2) endometrioid histology (82%) and recurrences confined to the vagina (86%). External beam with either the three-dimensional or intensity modulated radiation treatment technique was followed by a boost delivered with brachytherapy or external beam. Patients randomly assigned to receive chemotherapy were treated with once weekly cisplatin (40 mg/m2). Rates of acute toxicity were higher in patients treated with chemoradiation as compared with radiation treatment alone. Median PFS was longer for patients treated with radiation therapy alone as compared with chemotherapy and radiation (median PFS was not reached for RT v 73 months for chemoradiation, hazard ratio of 1.25 (95% CI, 0.75 to 2.07). At 3 years, 73% of patients treated definitively with radiation and 62% of patients treated with chemoradiation were alive and free of disease progression.

CONCLUSION

Excellent outcomes can be achieved for women with localized recurrences of endometrial cancer when treated with radiation therapy. The addition of chemotherapy does not improve PFS for patients treated with definitive radiation therapy for recurrent endometrial cancer and increases acute toxicity. Patients with low-grade and vaginal recurrences who constituted the majority of those enrolled are best treated with radiation therapy alone.

Review of brachytherapy clinical trials: a cross-sectional analysis of ClinicalTrials.gov

INTRODUCTION

Characterizing the landscape of clinical trials including brachytherapy can provide an overview of the current status and research trends which may guide further areas of investigation.

METHOD

We queried 449,849 clinical trials from the ClinicalTrials.gov registry using brachytherapy-related keywords from 1980 to 2023, yielding 245 multi-arm and 201 single-arm, brachytherapy trials. Multi-arm and single-arm brachytherapy trials were compared using 12 trial protocol elements.

RESULTS

The number of trials including brachytherapy has increased over time, with over 60% of trials registered in 2010 onwards. The majority of clinical trials were Phase 2 or 3, evaluated both safety and efficacy, and were funded by academic sponsors. The most common tumor sites evaluated in brachytherapy clinical trials include prostate, cervix, liver, endometrium, and breast.

CONCLUSION

There remains continued interest in clinical trials including brachytherapy focused on evaluation of novel delivery systems, treatment planning, and new indications. More brachytherapy clinical trials are needed to define the optimal clinical utilization and advance prospective research in this field.

Patient-specific cylinder templates for hybrid interstitial vaginal brachytherapy: Feasibility of automated 3-D design, 3D printing, and dosimetric outlook

PURPOSE

Delivering highly conformal treatment plans for high-dose rate vaginal brachytherapy using commercially available applicators can be challenging. A partially automated workflow is presented for the in-house modeling and 3D printing of patient-specific cylindrical templates (PSCTs), which facilitate placement of flexible intracavitary and interstitial needles. To demonstrate feasibility, we compare PSCT treatment plans to retrospective interstitial brachytherapy plans delivered at our center. PSCTs derived from these plans were 3D printed to test the validity of the auto-design process. To facilitate clinical implementation, we validated the steam sterilization compatibility of PSCTs printed using polyetheretherketone (PEEK).

METHODS AND MATERIALS

Plans for ten patients treated using a combination of vaginal cylinder and interstitial needles were compared to PSCT-based plans created for the same patient. DVH parameters for the HRCTV (V100, V150, V200, D90) and OARs (D2 cm3) were evaluated, as well as the number of needles used and the total interstitial length. Each planned PSCT was printed and compared to the intended needle geometry. 3D printed models were sterilization validated by an independent contractor for an autoclave protocol.

RESULTS

PSCT plans demonstrated advantages over template based perineal BT in reducing the total interstitial needle length required while preserving or improving HRCTV and OAR dosimetry. All printed PSCTs matched planned geometry.

CONCLUSIONS

PSCTs stand to be an alternative to current HDR-BT templates/applicators for patients with vaginal and locally recurrent endometrial cancers. Clinically equivalent or improved treatment plans can be created and devices to deliver these plans can be accurately printed and sterilized.

GEC-ESTRO (ACROP)-ABS-CBG Consensus Brachytherapy Target Definition Guidelines for Recurrent Endometrial and Cervical Tumors in the Vagina

PURPOSE

Representatives from the Gynecologic Groupe European de Curietherapie-European Society for Radiation Therapy and Oncology (GYN GEC-ESTRO), the American Brachytherapy Society (ABS), and the Canadian Brachytherapy Group (CBG) met to develop international consensus recommendations for target definitions for image-guided adaptive brachytherapy for vaginal recurrences of endometrial or cervical cancer.

METHODS AND MATERIALS

Seventeen radiation oncologists and 2 medical physicists participated. Before an in-person meeting each participant anonymously contoured 3 recurrent endometrial/cervical cancer cases. Participants contoured the residual gross primary tumor volume (GTV-T_res), a high-risk clinical target volume (CTV-T_HR), and an intermediate-risk clinical target volume (CTV-T_IR), on T2-weighted magnetic resonance images (MRIs). All contours were drawn using Falcon EduCase. Contours were reviewed at an in-person meeting during which a consensus document was created defining agreed-upon target definitions (Trial 1). After establishing these definitions, the group was sent one of the cases again (recurrent cervical cancer vaginal recurrence) and asked to contour the targets again (Trial 2). The Computerized Environment for Radiation Research (CERR) software (The Mathworks, Natwick, MA) was used to analyze the contours. Kappa statistics were generated to assess level of agreement between contours. A conformity index (CI), defined as the ratio between the intersection and union volume of a given pair of contours, was calculated. A simultaneous truth and performance level estimation (STAPLE) contour was created for the CTV-T_HR and CTV-T_IR for the postmeeting case.

RESULTS

Consensus definitions for GTV-T_res, CTV-T_HR, and CTV-T_IR were established. Kappa statistics (Trial 1/Trial 2) for GTV-T_res, CTV-T_HR, and CTV-T_IR were 0.536/0.583, 0.575/0.743 and 0.522/0.707. Kappa statistics for Trial 2 for the CTV-T_HR and CTV-T_IR showed "substantial" agreement while the GTV-T_res remained at moderate agreement.

CONCLUSIONS

This consensus provides recommendations to facilitate future collaborations for MRI-guided adaptive brachytherapy target definitions in endometrial/cervical vaginal recurrences.

The Efficacy of Psychological Care and Chinese Herbal Decoction in Postoperative Chemotherapy Patients with Endometrial Cancer

Background. In recent years, the incidence of endometrial cancer (EC) has been on the rise worldwide. The purpose of this study was to investigate the efficacy of psychological care and Chinese herbal decoction in EC patients with postoperative chemotherapy. Methods. 80 EC patients with postoperative chemotherapy were randomly divided into the observation group and control group. The control group was given psychotherapy. The observation group was given psychological care plus Chinese herbal decoction treatment. HE4, CA125, traditional Chinese medicine (TCM) syndrome scores, toxic and side effects, and quality of life scores before and after treatment were observed. Results. After treatment, the total effective rate of the observation group was higher than that of the control group. After treatment, serum HE4 and CA125 levels in the observation group were lower than those in the control group. In addition, CD3+ and CD4+ levels in the observation group were higher than those in the control group. Meanwhile, the CD8+ level in the observation group was lower than that in the control group. Compared with the control group, the quality of life in the observation group was significantly improved, and the incidence of adverse reactions was reduced. Conclusion. Chinese herbal decoction combined with psychological care can improve the clinical symptoms, alleviate the toxic and side effects, and improve the life quality of EC patients with postoperative chemotherapy.

Recurrent Endometrial Cancer: Local and Systemic Treatment Options

The treatment of recurrent endometrial cancer is a challenge. Because of earlier treatments and the site of locoregional recurrence, in the vaginal vault or pelvis, morbidity can be high. A total of about 4 to 20% of the patients with endometrial cancer develop a locoregional recurrence, mostly among patients with locally advanced disease. The treatment options are dependent on previous treatments and the site of recurrence. Local and locoregional recurrences can be treated curatively with surgery or (chemo)radiotherapy with acceptable toxicity and control rates. Distant recurrences can be treated with palliative systemic therapy, i.e., first-line chemotherapy or hormonal therapy. Based on the tumor characteristics and molecular profile, there can be a role for immunotherapy. The evidence on targeted therapy is limited, with no approved treatment in the current guidelines. In selected cases, there might be an indication for local treatment in oligometastatic disease. Because of the novel techniques in radiotherapy, disease control can often be achieved at limited toxicity. Further studies are warranted to analyze the survival outcome and toxicity of newer treatment strategies. Patient selection is very important in deciding which treatment is of most benefit, and better prediction models based on the patient- and tumor characteristics are necessary.

Clinical results of image-guided interstitial brachytherapy with or without external beam radiotherapy for postsurgical vaginal recurrence of cervical and endometrial cancers

Purpose

This study aimed to evaluate the clinical outcome and efficacy of image-guided interstitial brachytherapy (ISBT) for postsurgical vaginal recurrence of cervical and endometrial cancers.

Materials and methods

The study included 11 patients who received CT-based image-guided high-dose-rate ISBT with or without external beam radiotherapy (EBRT). Local control, progression-free survival, and treatment-related toxicities were evaluated retrospectively.

Results

Of the 11 patients, 4 underwent ISBT with EBRT and the other 7 ISBT alone; two of the latter patients received previous pelvic radiotherapy. After a median follow-up of 43.9 months (range 3.9–92.7 months), the 2-year local control rate was 100%. The median equivalent doses in 2 Gy fractions received by at least 90% of the clinical target volume for ISBT with versus without EBRT were 82.2 Gy (range 60.4–84.2 Gy) versus 69.0 Gy (range 50.8–98.2 Gy). The 2-year progression-free survival rates after ISBT with versus without EBRT were 75% versus 80%, and the difference was not significant (p = 0.74). Grade 3 late toxicities occurred in two patients.

Conclusion

Our radiotherapy strategy using image-guided ISBT, either with or without EBRT, for postsurgical vaginal recurrence showed effective treatment outcomes.

Image-Guided Brachytherapy for Salvage Reirradiation: A Systematic Review

Simple Summary

Local recurrence in gynecological malignancies occurring in a previously irradiated field is a difficult clinical issue. Curative-intent treatment is salvage surgery and is associated with non-negligible peri-operative morbidity and has a substantial impact on long-term quality of life. Reirradiation, using three-dimensional image-guided brachytherapy (3D-IGBT), might be a suitable alternative, especially in non-operable patients. The aim of this review is to report outcomes and toxicities of reirradiation 3D-IGBT in this context. 3D-IGBT appears to be a feasible alternative to salvage surgery in inoperable patients, with an acceptable outcome for patients who have no other curative therapeutic options, however long-term toxicities were high in some studies. Each case should be referred to highly experienced expert centers.

Abstract

Background: Local recurrence in gynecological malignancies occurring in a previously irradiated field is a challenging clinical issue. The most frequent curative-intent treatment is salvage surgery. Reirradiation, using three-dimensional image-guided brachytherapy (3D-IGBT), might be a suitable alternative. We reviewed recent literature concerning 3D-IGBT for reirradiation in the context of local recurrences from gynecological malignancies. Methods: We conducted a large-scale literature research, and 15 original studies, responding to our research criteria, were finally selected. Results: Local control rates ranged from 44% to 71.4% at 2–5 years, and overall survival rates ranged from 39.5% to 78% at 2–5 years. Grade ≥3 toxicities ranged from 1.7% to 50%, with only one study reporting a grade 5 event. Results in terms of outcome and toxicities were highly variable depending on studies. Several studies suggested that local control could be improved with 2 Gy equivalent doses >40 Gy. Conclusion: IGBT appears to be a feasible alternative to salvage surgery in inoperable patients or patients refusing surgery, with an acceptable outcome for patients who have no other curative therapeutic options, however at a high cost of long-term grade ≥3 toxicities in some studies. We recommend that patients with local recurrence from gynecologic neoplasm occurring in previously irradiated fields should be referred to highly experienced expert centers. Centralization of data and large-scale multicentric international prospective trials are warranted. Efforts should be made to improve local control while limiting the risk of toxicities.

High-dose-rate interstitial brachytherapy for vaginal endometrial cancer recurrence after prior surgery and radiotherapy

PURPOSE

Characterize the clinical outcomes of endometrial cancer vaginal recurrences after previous surgery and radiation therapy treated with reirradiation including image-guided interstitial high-dose-rate (HDR) brachytherapy.

METHODS AND MATERIALS

A single-institution retrospective study identifying women receiving reirradiation for vaginal recurrence of endometrial cancer between 2004 and 2017.

RESULTS

Twenty-three women had vaginal recurrences of endometrial cancer, median 13.7 months (range 3.5-104.9) from initial radiation. All received reirradiation with interstitial HDR brachytherapy, and seven also received external beam radiation. Median reirradiation EQD2_10 was 48 Gy (range 24.0-68.81), and median cumulative EQD2_10 was 106.25 Gy (range 62.26-122.0). Median follow-up after reirradiation was 40.2 months (range 4.5-112.7). At 3 years, overall survival was 56%, cancer-specific survival was 61%, and disease-free survival was 46%. 14 patients experienced disease recurrence; 10 including distant sites, one at a regional node only. Three patients experienced local recurrences, two of whom did not complete the prescribed course of reirradiation. The overall crude local control rate was 87%. Three patients experienced Grade 3 vaginal toxicity. There was no bladder or rectal toxicity with Grade >2.

CONCLUSIONS

Reirradiation including interstitial HDR brachytherapy is a promising option for vaginal recurrences of endometrial cancer after prior radiation, with high rate of local control and acceptable toxicity. However, distant failure is common. Further studies are needed to determine cumulative radiation dose limits and the role of systemic therapy in this scenario.

Endometrial cancer: A society of gynecologic oncology evidence-based review and recommendations, part II

In 2014, the Society of Gynecologic Oncology's Clinical Practice Committee published a clinical update reviewing the treatment of women with endometrial cancer. At that time, there had been significant advances in the diagnosis, work-up, surgical management, and available treatment options allowing for more optimal care of affected women. This manuscript, Part II in a two-part series, includes specific recommendations on treatment of recurrent disease, post treatment surveillance and survivorship, considerations for younger women, and special situations. Part I covered histopathology and molecular pathology, risk factors, presentation and diagnostic approach, surgical approach and adjuvant therapy.

COVID-19 impact on timing of brachytherapy treatment and strategies for risk mitigation

PURPOSE

The purpose of this study was to highlight the importance of timely brachytherapy treatment for patients with gynecologic, breast, and prostate malignancies, and provide a framework for brachytherapy clinical practice and management in response to the COVID-19 pandemic.

METHODS AND MATERIALS

We review amassing evidence to help guide the management and timing of brachytherapy for gynecologic, breast, and prostate cancers. Where concrete data could not be found, peer-reviewed expert opinion is provided.

RESULTS

There may be a significant negative impact on oncologic outcomes for patients with gynecologic malignancies who have a delay in the timely completion of therapy. Delay of prostate or breast cancer treatment may also impact oncologic outcomes. If a treatment delay is expected, endocrine therapy may be an appropriate temporizing measure before delivery of radiation therapy. The use of shorter brachytherapy fractionation schedules will help minimize patient exposure and conserve resources.

CONCLUSIONS

Brachytherapy remains a critical treatment for patients and may shorten treatment time and exposure for some. Reduced patient exposure and resource utilization is important during COVID-19. Every effort should be made to ensure timely brachytherapy delivery for patients with gynecologic malignancies, and endocrine therapy may help temporize treatment delays for breast and prostate cancer patients. Physicians should continue to follow developing institutional, state, and federal guidelines/recommendations as challenges in delivering care during COVID-19 will continue to evolve.

Vaginal recurrence of endometrial cancer: MRI characteristics and correlation with patient outcome after salvage radiation therapy

Purpose

To evaluate MRI characteristics in vaginal recurrence of endometrial cancer (EC) including tumor volume shrinkage during salvage radiotherapy, and to identify imaging features associated with survival.

Methods

Patients with vaginal recurrence of EC treated with external beam radiotherapy (EBRT) followed by brachytherapy (BT), and with available pelvic MRI at two time points: baseline and/or before BT were retrospectively identified from 2004 to 2017. MRI features including recurrence location and tissue characteristics on T2- and T1-weighted images were evaluated at baseline only. Tumor volumes were measured both at baseline and pre-BT. Survival rates and associations were evaluated by Cox regression and Fisher’s exact test, respectively.

Results

Sixty-two patients with 36 baseline and 50 pre-BT pelvic MRIs were included (24/62 with both MRIs). Vaginal recurrence of EC was most commonly located in the vaginal apex (27/36, 75%). Tumors with a post-contrast enhancing peripheral rim or low T2 signal rim at baseline showed longer recurrence-free survival (RFS) (HR 0.2, 95% CI 0.1–0.9, P < 0.05 adjusted for histology; HR 0.2, 95% CI 0.1–0.8, P < 0.05, respectively). The median tumor shrinkage at pre-BT was 69% (range 1–99%). Neither absolute tumor volumes nor volume regression at pre-BT were associated with RFS. Lymphovascular space invasion (LVSI) at hysterectomy and adjuvant RT were associated with recurrence involving the distal vagina (both P < 0.05).

Conclusion

Vaginal recurrences with rim enhancement at baseline MRI predicted improved RFS, while tumor volume shrinkage at pre-BT did not. Distal vaginal recurrence was more common in patients with LVSI and adjuvant RT at EC diagnosis.

Salvage Re-irradiation With Single-modality Interstitial Brachytherapy for the Treatment of Recurrent Gynaecological Tumours in the Pelvis: A Multi-institutional Study

AIMS

Recurrent gynaecological tumours can cause significant morbidity with limited salvage options. This study investigates the strategy of salvage single-modality interstitial brachytherapy (SM-ISBT) for recurrent gynaecological pelvic cancer at two specialised ISBT centres.

MATERIALS AND METHODS

Patients who had received salvage SM-ISBT for pelvic recurrence of gynaecological cancers from September 2008 to January 2017 were included. None had distant metastasis at the time of recurrence. Local control, progression-free and overall survival and long-term toxicities were evaluated.

RESULTS

Twenty-six patients with a median follow-up of 24 months (range 2.5-106.3 months) after SM-ISBT were included. Primary cancer sites were endometrium (20), cervix (4), vulva (1) and vagina (1). All patients had prior whole-pelvic external beam irradiation and 16 had prior brachytherapy. The median disease-free survival prior to SM-ISBT was 20.3 months (interquartile range 9.9-30.5). SM-ISBT was delivered with high dose rate technique over three to six fractions. The median high-risk clinical target volume was 34.6 cm³, with a median D90 of 29.1 Gy (range 16.1-64.6). The median bladder, rectum and sigmoid D2cm³ were 15.5, 18.7 and 3.7 Gy, respectively. After SM-ISBT, complete and partial responses were achieved in 17 (64%) and 5 (19%) patients, respectively. Two (7.4%) patients had grade 3 toxicities (both vaginal stenosis), with no grade 4 complications. Eighteen patients (69%) recurred, including local, regional and metastatic in 14 (54%), 8 (30%) and 5 (19%) patients, respectively. Two-year local control, progression-free survival and overall survival were 50, 38 and 78%, respectively. In follow-up, 12 patients (46%) remained in local control.

CONCLUSIONS

Salvage SM-ISBT re-irradiation for pelvic recurrence of gynaecological malignancies was feasible and safe. With limited salvage options, the local control obtained in more than a quarter of patients seems reasonable. Further efforts are needed to establish a consensus about the optimal patient selection, dose fractionation, implant technique and combination with systemic therapies.

MRI-based interstitial brachytherapy for vaginal tumors: A multi-institutional study on practice patterns, contouring, and consensus definitions of target volumes

PURPOSE

Interstitial brachytherapy (ISBT) can be effective for vaginal tumors due to its ability to deliver conformal treatment with 3D planning. As there is no consensus for 3D vaginal brachytherapy (BT) contouring, the goals of this study are to evaluate the variability in practices and contouring, and to develop consensus concepts on target definitions.

METHODS

A survey/contouring study was conducted with 16 radiation oncologists from 10 Canadian academic centers. The study included three vaginal ISBT cases. Participants were provided staging, prebrachytherapy (pre-BT), and BT MRIs. Participants responded to a questionnaire and contoured on the provided images. Agreement between contours was analyzed. A meeting was held to develop consensus definitions of targets.

RESULTS

Median ISBT experience was 3.5 years. All 16 participants regularly contour with MRI, whereas three also plan on MRI. For the three cases, there was variation into how CTV_HR and CTV_IR was defined. Kappa statistics showed higher agreement with bulky tumors (mean 0.59) as compared with small residual tumors (mean 0.29). For all cases, kappa was highest in pre-BT GTV_res as compared with BT GTV_res (mean 0.58, 0.46). Consensus concepts to define targets were developed.

CONCLUSIONS

Variations exist in how ISBT targets are defined for vaginal tumors. Highest contouring variability was seen with small residual at BT. Contouring is more consistent on pre-BT MRI as compared with BT MRI suggesting a needle distortion effect. Consensus CTV_HR and CTV_IR definitions have been developed and further work is warranted to establish international standards.

Outcomes after definitive re-irradiation with 3D brachytherapy with or without external beam radiation therapy for vaginal recurrence of endometrial cancer

BACKGROUND

Limited outcome data exists on salvage re-irradiation for vaginal relapse of previously-irradiated endometrial cancer. We report our 10-year experience with management of vaginal recurrence using definitive intent re-irradiation brachytherapy with or without EBRT.

METHODS

A retrospective review was performed on 22 patients treated with definitive-intent re-irradiation brachytherapy ± EBRT for vaginal recurrence of endometrial cancer. The cumulative rectosigmoid and bladder D2cc (EQD2) were limited to <75 Gy and <90 Gy, respectively. Kaplan-Meier and Cox proportional hazards modeling were used to estimate survival. Severe (grade 3 or higher) radiation-related toxicities, defined according to CTCAE v4, were recorded.

RESULTS

Prior radiation therapy consisted of vaginal brachytherapy (54.5%), pelvic EBRT (22.7%), or combination pelvic EBRT and brachytherapy (22.7%). Median re-irradiation interval was 26.6 months. Salvage re-irradiation consisted of EBRT with brachytherapy in 50.0% and brachytherapy alone in 50.0%. Median HR-CTV D90 (EQD2) was 64.5 Gy (IQR: 49.6-75.8). Median cumulative D2cc for bladder, rectum, and sigmoid were 72.1 Gy (range: 30.3-81.8), 70.6 Gy (range: 32.0-80.5), and 52.7 Gy (range: 29.6-75.3), respectively. At a median follow-up of 27.6 months, 3-year local control, regional control, disease-free survival, and overall survival rates were 65.8%, 76.6%, 40.8%, and 68.1%, respectively. There were no grade ≥ 3 acute or late rectosigmoid or bladder toxicities.

CONCLUSION

Re-irradiation with 3D conformal brachytherapy for vaginal recurrence is feasible and safe as long as cumulative dose to surrounding normal organs is limited, and offers a chance to potentially salvage 40% of patients presenting with vaginal recurrence in the setting of prior pelvic radiation.

Image-based multichannel vaginal cylinder brachytherapy for the definitive treatment of gynecologic malignancies in the vagina

PURPOSE

Brachytherapy is integral to vaginal cancer treatment and is typically delivered using an intracavitary single-channel vaginal cylinder (SCVC) or an interstitial brachytherapy (ISBT) applicator. Multi-channel vaginal cylinder (MCVC) applicators allow for improved organ-at-risk (OAR) sparing compared to SCVC while maintaining target coverage. We present clinical outcomes of patients treated with image-based high dose-rate (HDR) brachytherapy using a MCVC.

METHODS AND MATERIALS

Sixty patients with vaginal cancer (27% primary vaginal and 73% recurrence from other primaries) were treated with combination external beam radiotherapy (EBRT) and image-based HDR brachytherapy utilizing a MCVC if residual disease thickness was 7 mm or less after EBRT. All pts received 3D image-based BT to a total equivalent dose of 70-80 Gy.

RESULTS

The median high-risk clinical target volume was 24.4 cm³ (interquartile range [IQR], 14.1), with a median dose to 90% of 77.2 Gy (IQR, 2.8). After a median follow-up of 45 months (range, 11-78), the 4-year local-regional control, distant control, DFS, and OS rates were 92.6%, 76.1%, 64.0%, and 67.2%, respectively. The 4-year LRC rates were similar between the primary vaginal (92%) and recurrent (93%) groups (p = 0.290). Pts with lymph node positive disease had a lower rate of distant control at 4 years (22.7% vs. 89.0%, p < 0.001). There were no Grade 3 or higher acute complications. The 4-year rate of late Grade 3 or higher toxicity was 2.7%.

CONCLUSIONS

Clinical outcomes of pts with primary and recurrent vaginal cancer treated definitively in a systematic manner with combination EBRT with image-guided HDR BT utilizing a MCVC applicator demonstrate high rates of local control and low rates of severe morbidity. The MCVC technique allows interstitial implantation to be avoided in select pts with ≤7 mm residual disease thickness following EBRT while maintaining excellent clinical outcomes with extended 4-year follow-up in this rare malignancy.