A novel low dose fractionation regimen for adjuvant vaginal brachytherapy in early stage endometrioid endometrial cancer

Dosimetric Evaluation of Organs at Risk From SAVE Protocol

PURPOSE

The objective of this work was to evaluate dosimetric characteristics to organs at risk (OARs) from short-course adjuvant vaginal cuff brachytherapy (VCB) in early endometrial cancer compared with standard of care (SOC) in a multi-institutional prospective randomized trial.

METHODS AND MATERIALS

SAVE (Short Course Adjuvant Vaginal Brachytherapy in Early Endometrial Cancer Compared to Standard of Care) is a prospective, phase 3, multisite randomized trial in which 108 patients requiring VCB were randomized to an experimental short-course arm (11 Gy × 2 fractions [fx] to surface) and SOC arm. Those randomized to the SOC arm were subdivided into treatment groups based on treating physician discretion as follows: 7 Gy × 3 fx to 5 mm, 5 to 5.5 Gy × 4 fx to 5 mm, and 6 Gy × 5 fx to surface. To evaluate doses to OARs of each SAVE cohort, the rectum, bladder, sigmoid, small bowel, and urethra were contoured on planning computed tomography, and doses to OARs were compared by treatment arm. Absolute doses for each OAR and from each fractionation scheme were converted to 2 Gy equivalent dose (EQD23). Each SOC arm was compared with the experimental arm separately using 1-way analysis of variance, followed by pairwise comparisons using Tukey's honestly significant difference test.

RESULTS

The experimental arm had significantly lower doses for rectum, bladder, sigmoid, and urethra compared with the 7 Gy × 3 and 5 to 5.5 Gy × 4 fractionation schemes; however, the experimental arm did not differ from the 6 Gy × 5 fractionation scheme. For small bowel doses, none of the SOC fractionation schemes were statistically different than the experimental. The highest EQD23 doses to the examined OARs were observed to come from the most common dose fractionation scheme of 7 Gy × 3 fx. With a short median follow-up of 1 year, there have been no isolated vaginal recurrences.

CONCLUSIONS

Experimental short-course VCB of 11 Gy × 2 fx to the surface provides a comparable biologically effective dose to SOC courses. Experimental short-course VCB was found to reduce or be comparable to D2cc and D0.1cc EQD23 doses to rectum, bladder, sigmoid, small bowel, and urethra critical structures. This may translate into a comparable or lower rate of acute and late adverse effects.

Vaginal cuff brachytherapy for endometrial cancer: a review of major clinical trials with a focus on fractionation

The use of vaginal cuff brachytherapy in the adjuvant management of endometrial cancer has increased over time. Recommendations from the American Brachytherapy Society, American Society of Radiation Oncology, and European Society for Medical Oncology help to guide the application of vaginal cuff brachytherapy. However, wide variation in practice remains regarding treatment techniques. This article reviews the use of vaginal cuff brachytherapy in the post-operative management of endometrial cancer. It covers risk stratification, treatment rationale, outcomes, and treatment planning recommendations with a specific focus on dose-fractionation regimens. The authors performed a thorough literature review of articles pertinent to the goals of this review. Also presented are early results of the Short Course Adjuvant Vaginal Cuff Brachytherapy in Early Endometrial Cancer Compared with Standard of Care (SAVE) trial of a two-fraction vaginal cuff brachytherapy regimen.

Adjuvant vaginal cuff brachytherapy for early-stage endometrial cancer results in excellent disease control with minimal toxicity. The PORTEC-2 trial showed that vaginal cuff brachytherapy is non-inferior to external beam radiation for vaginal recurrence in patients at high-intermediate risk. Vaginal cuff brachytherapy may also be used as a boost following external beam radiation in combination with chemotherapy for high-risk histologies. Numerous techniques can be used for vaginal cuff brachytherapy, including various medical devices, dose-fractionation schedules, and treatment planning approaches. The early control results of the SAVE trial are promising and we are hopeful that this trial establishes two fraction regimens as a viable option for vaginal cuff brachytherapy.

Biological Planning of Radiation Dose Based on In Vivo Dosimetry for Postoperative Vaginal-Cuff HDR Interventional Radiotherapy (Brachytherapy)

(1) Background: Postoperative vaginal-cuff HDR interventional radiotherapy (brachytherapy) is a standard treatment in early-stage endometrial cancer. This study reports the effect of in vivo dosimetry-based biological planning for two different fractionation schedules on the treatment-related toxicities. (2) Methods: 121 patients were treated. Group A (82) received 21 Gy in three fractions. Group B (39) received 20 Gy in four fractions. The dose was prescribed at a 5 mm depth or to the applicator surface according to the distance between the applicator and the rectum. In vivo dosimetry measured the dose of the rectum and/or urinary bladder. With a high measured dose, the dose prescription was changed from a 5 mm depth to the applicator surface. (3) Results: The median age was 66 years with 58.8 months mean follow-up. The dose prescription was changed in 20.7% of group A and in 41% of group B. Most toxicities were grade 1–2. Acute urinary toxicities were significantly higher in group A. The rates of acute and late urinary toxicities were significantly higher with a mean bladder dose/fraction of >2.5 Gy and a total bladder dose of >7.5 Gy. One patient had a vaginal recurrence. (4) Conclusions: Both schedules have excellent local control and acceptable rates of toxicities. Using in vivo dosimetry-based biological planning yielded an acceptable dose to the bladder and rectum.

Vaginal cuff brachytherapy: do we need to treat to more than a two-centimeter active length?

Purpose

American Brachytherapy Society (ABS) guidelines recommend using a 3-5 cm active length (AL) when treating vaginal cuff (VC) in adjuvant setting of endometrial cancer (EC). The purpose of this study was to evaluate local control and toxicity, using an AL of 1 or 2 cm and immobilization with a traditional table-mounted (stand) or patient-mounted (suspenders) device.

Material and methods

Between 2005 and 2019, 247 patients with EC were treated with adjuvant high-dose-rate vaginal cuff (HDR-VC) brachytherapy with or without external beam radiation (EBRT). Treatment was prescribed to a 0.5 cm depth, with an AL of 1 or 2 cm, using stand or suspenders. VC boost after EBRT was typically administered with 2 fractions of 5.5 Gy, while VC brachytherapy alone was typically applied with 3 fractions of 7 Gy or 5 fractions of 5.5 Gy.

Results

The combination of suspender immobilization and an AL of 2 cm (n = 126, 51%) resulted in 5-year local control of 100%. An AL of 2 cm compared to 1 cm correlated with better local control (99.1% vs. 88.5%, p = 0.0479). Regarding immobilization, suspenders correlated with improved local control compared to stand (100% vs. 86.7%, p = 0.0038). Immobilization technique was significantly correlated with AL (p < 0.0001). Only 5 (2.0%) patients experienced grade ≥ 3 toxicity, all of whom received EBRT.

Conclusions

In the present series, an AL of 2 cm provided excellent local control, while 1 cm was inadequate. Suspender immobilization was a practical alternative to stand immobilization in HDR brachytherapy of the vaginal cuff.

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.

Long-term outcomes of intensity-modulated radiation therapy (IMRT) and high dose rate brachytherapy as adjuvant therapy after radical hysterectomy for cervical cancer

OBJECTIVE

Compared with 3D-planned pelvic radiation, intensity-modulated radiation therapy (IMRT) has been shown to reduce acute toxicity in cervical cancer patients after radical hysterectomy. This study evaluated late toxicity and patterns of failure after post-operative pelvic IMRT interdigitated weekly with high dose rate brachytherapy.

METHODS

This retrospective study included 53 cervical cancer patients treated between January 2006 and August 2019 with radical hysterectomy, lymphadenectomy, and post-operative IMRT and high dose rate brachytherapy. The decision to include chemotherapy was made by the treating gynecologic oncologist based on patient-specific criteria including positive pelvic lymph nodes, positive surgical margins, or positive parametrial invasion. The actuarial rates of genitourinary and gastrointestinal toxicity, vaginal cuff/regional nodal/distant failure, and overall survival were calculated using the Kaplan-Meier method.

RESULTS

Median follow-up was 70 months (range 5.4-148) months and age at diagnosis was 47 (range 24-73) years. The 2018 International Federation of Gynecology and Obstetrics (FIGO) clinical stages were IB1 (n=19), IB2 (n=7), IIB (n=7), IIIC1 (n=19), and IIIC2 (n=1). Median radiation dose delivered in 160 cGy daily fractions was 5120 (range 4640-5120) cGy. Median brachytherapy dose prescribed to the vaginal surface delivered in six weekly fractions was 2400 (range 1200-4800) cGy. Concurrent chemotherapy was delivered in 35 (66%) patients. There were no acute grade >3 genitourinary or gastrointestinal toxicities. Late grade >3 occurred in two (3.8%) patients, including a small bowel obstruction and a ureteral stricture. The 5-year actuarial rate for gastrointestinal or genitourinary toxicity was 1.9%. There were no vaginal cuff recurrences. The 5-year actuarial rates for regional nodal failure, distant failure outside the radiation field, any failure, and overall survival were 11%, 11%, 14%, and 85%, respectively.

CONCLUSIONS

Post-operative IMRT with high dose rate brachytherapy for patients with cervical cancer is associated with excellent outcomes and limited rates of radiation-related non-hematologic toxicity.

Low-Dose Adjuvant Cylinder Brachytherapy for Endometrioid Endometrial Cancer

PURPOSE

Our purpose was to evaluate outcomes and sites of failure for women with early stage endometrial adenocarcinoma treated with adjuvant high-dose-rate (HDR) vaginal brachytherapy (VB) with a low dose scheme.

METHODS AND MATERIALS

Retrospective review identified 318 patients with International Federation of Gynecology and Obstetrics (FIGO) stage I-II endometrioid endometrial cancer who received adjuvant HDR VB to a dose of 24 Gray (Gy) in 6 fractions from 2005 to 2017. Patients with <6 months follow-up were excluded. Dose was prescribed to cylinder surface and computerized tomography (CT) imaging was performed before each fraction to assess cylinder placement. Rates of vaginal relapse (VR), pelvic nodal relapse, distant metastasis, recurrence-free survival, and overall survival were calculated by Kaplan-Meier method. Univariate analysis was performed by log rank test or Cox proportional hazards. Pretreatment CT images were analyzed for patients with VR.

RESULTS

Median follow-up was 42 months for 243 patients. The 3-year rates of VR, pelvic nodal relapse, distant metastasis, recurrence-free survival, and overall survival were 1.9%, 1.5%, 4.3%, 94.1%, and 98.9%, respectively. The 3-year VR rates by Gynecologic Oncology (GOG)-99 risk groups were 0%, 1.4%, and 3.2% for low risk, low-intermediate risk, and high-intermediate risk (HIR) disease (P = .5). By Post-operative Radiation Therapy in Endometrial Carcinoma (PORTEC) risk stratification, 3-year VR rate was 1.3% for HIR disease. On review of pretreatment CT images of the 6 patients with VR, 3 patients had relapse at the introitus outside of the treated vaginal length, and 3 had in-field recurrence at the vaginal apex. Higher body mass index (BMI) was associated with VR, with a 14% increase in risk per BMI unit (kg/m², P = .02). There were no reported grade 2 GI or any grade 3 toxicities.

CONCLUSIONS

Adjuvant HDR VB with a low-dose regimen results in excellent clinical outcomes for patients with early stage endometrioid endometrial cancer. Patients with higher BMI may be at increased risk of VR, and additional study is needed to optimize brachytherapy treatment parameters.

Clinical and Dosimetric Implications of Intrafractional Cylinder Movement During Vaginal Cuff Brachytherapy

Introduction To quantify the dosimetric and clinical effects of intrafractional cylinder movement in patients receiving high-dose-rate vaginal cuff brachytherapy (VBT) without a formal immobilization device and the implication of motion on institutional clinical outcomes. Methods From 2013-2018, 119 patients were treated with VBT with no formal immobilization device at a single institution. As a quality assessment study, pre-and post-cylinder brachytherapy kilovoltage (kV) images were acquired for 37 fractions in nine consecutive patients who underwent VBT and clinical care representative of institutional practice standards. The D90 and D90 EqD2 were calculated according to each patient's average intrafractional movement throughout the treatment course. The D2cc for organs-at-risk (OARs) were also re-evaluated following the simulated movements. The survival outcomes and toxicity were recorded from the 119 patients. Toxicity was graded as per Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. Results The measured mean ± standard deviation movement was 5.0 mm ± 3.5, with 62% moving caudad. The D90 from each patient's maximum and average movements were lower than the pre-planned doses: 71%, and 89%, respectively. The doses to the OARs were lower than the pre-planned doses. After a median follow-up of 20 months, there were three local recurrences with a median time of 14.5 months (range: 10-31). There were two acute grade 3+ toxicities and one late grade 3+ toxicity. There was a moderate correlation (r = 0.40) between body mass index (BMI) and intrafraction movement with caudad being more common in smaller BMIs (p = 0.0216). Conclusions Intrafractional vaginal cylinder movement without a table fixation device is about 5.0 mm, with the majority of movements moving caudad. While institutional outcomes suggest that local control may not be compromised, consideration of more formal immobilization devices is warranted, especially for those patients with lower BMIs.

The vaginal cylinder: Misunderstood, misused, or trivial? An in-depth dosimetric and multiinstitutional outcome investigation

PURPOSE

The purpose of the study was to investigate the impact on dose distribution and radiobiological metrics of common high-dose-rate vaginal brachytherapy treatment parameters and to analyze multiinstitutional data for clinically significant impact on outcomes in early-stage endometrial cancer.

METHODS AND MATERIALS

Treatment plans were created for all combinations of prescription parameters and used to quantify the dosimetric impact of each parameter and to estimate the dose delivered using common voxel-integrated radiobiological metrics. A rating system, based on risk grouping from GOG and PORTEC trials, was used to consolidate staging information into a cancer "aggressiveness" measure. Correlations between the rating, toxicity, disease recurrence, and plan parameters were investigated.

RESULTS

When prescribing to 5 mm depth, the variation caused by the diameter was very large across all dose metrics, ranging from 51% to 175% increase with the most divergence in BED_max. For surface prescription, changing the cylinder diameter from 4 cm to 2 cm caused the dose metrics of BED_min, D_min, and gBEUD (a = -3) to increase by 117%, 67%, and 52%, respectively. Prescription to 5-mm depth caused changes across all dose metrics of 260% compared with surface prescription for a 2-cm cylinder. Deeper prescription point (p = 0.005) and longer treatment length (p = 0.01) were correlated with increased stenosis rates. No correlation between recurrence and any plan parameter was found.

CONCLUSIONS

Dramatic differences in dose distributions arise by small variations of plan parameters, with large impact on rates of vaginal stenosis, but no clear relation with local recurrence. To help radiation oncologists interpret the magnitude of these effects for their patients, we created a tool that allows comparison between dose and fractionation parameters.

Do vaginal recurrence rates differ among adjuvant vaginal brachytherapy regimens in early-stage endometrial cancer?

PURPOSE

We sought to retrospectively examine clinical outcomes for three adjuvant vaginal high-dose-rate (HDR) brachytherapy regimens after hysterectomy for early-stage endometrial cancer.

METHODS

Included were women of all ages from two independent hospital systems diagnosed with Stage I-II endometrial cancer of any grade between 2000 and 2016 who underwent hysterectomy followed by adjuvant vaginal cylinder HDR brachytherapy with either 7.0 Gy × 3 fractions prescribed to 0.5 cm vaginal depth, 6.5 Gy × 3 fractions prescribed to 0.5 cm vaginal depth, or 6.0 Gy × 5 fractions prescribed to the vaginal surface. Outcomes included vaginal recurrence (VR), pelvic recurrence, distant recurrence, locoregional recurrence, recurrence-free survival, and overall survival.

RESULTS

Of the 348 women, 45 (13%) received 7.0 Gy × 3 fractions, 259 (74%) received 6.5 Gy × 3 fractions, and 44 (13%) received 6.0 Gy × 5 fractions. Women receiving 5-fraction brachytherapy were more likely to be younger with a higher performance status. At a median follow-up of 4.5 years, VR rates were 2.2%, 0.8%, and 4.5%, respectively. Multivariate analysis revealed no significant differences in the risks for VR among brachytherapy regimens. Risks for VR, pelvic recurrence, distant recurrence, locoregional recurrence, recurrence-free survival, and overall survival did not differ between propensity score-matched five- and 3-fraction brachytherapy cohorts.

CONCLUSIONS

VR rates after hysterectomy and adjuvant vaginal brachytherapy for early-stage endometrial cancer were low and not significantly different by HDR dose fractionation.

Quality of life and oncological outcome in endometrial cancer patients after vaginal brachytherapy: comparison of two dosing schemes

PURPOSE

Vaginal brachytherapy reduces the risk of local recurrence and was shown to be equieffective in preventing vaginal vault recurrence, but less toxic compared to external-beam radiotherapy in a subset of high intermediate-risk endometrial cancer patients and is administered as single adjuvant treatment in those patients. Different radiotherapeutic approaches with various dosing schemes exist toward brachytherapy. The aim of this study was to compare the outcome and long-term quality of life after brachytherapy with two different high-dose-rate dosing schemes.

METHODS

Retrospective analysis was conducted of the recurrence and survival rates of 104 patients with endometrial cancer FIGO stage I-II that underwent adjuvant brachytherapy with three times 5 Gy or four times 5 Gy to the upper two-thirds of the vaginal vault in two different institutions between January 2010 and December 2013. Quality of life was assessed by EORTC QLQ-30 questionnaire and EN 24 module.

RESULTS

The vaginal vault recurrence rates were 4.9% and 5.0% for patients treated with 3 × 5 Gy and 4 × 5 Gy, respectively (p = 0.98). We did not observe a difference in pelvic recurrence (p = 0.96), overall survival (p = 0.33) or quality of life between the different radiotherapy regimens. Metastatic recurrence and the use of chemotherapy contribute to impairment on quality of life. Younger patients (< 70 years) reported worse emotional functioning (p = 0.02) and higher symptom scales of diarrhea (p = 0.01) and financial problems (p = 0.03). Sexual activity was lower in patients younger than 70 years (p = 0.05).

CONCLUSIONS

Further prospective studies are needed to evaluate the effect of dosing schemes on recurrence rates and quality of life. Younger patients (< 70 years) seem to experience greater reduction in quality of life due to endometrial cancer diagnosis.

Retrospective Analysis of Intravaginal Brachytherapy in Adjuvant Treatment of Early Endometrial Cancer

The aim of this study was to determine the role of adjuvant endovaginal brachytherapy HDR (High Dose Rate) or observation, as well as identification of risk factors of tumor recurrence. The study included 178 women after radical hysterectomy. All patients belonged to the group of low- and medium-risk stage I FIGO. Analysis consisted of 3-, 5-, and 10-year OS, DFS, and LRFS in both groups. Follow-up was more than 6.5 years. The 5-OS, 5-DFS, and 5-LRFS were 93%, 96%, and 98% in the treated group and 95%, 94%, and 96% in the observed group, respectively. These differences were not statistically significant. There was a statistically significant difference in 5-OS in the treated group, between low- and medium-risk subgroups (100% versus 87.55%, p = 0.018). There was a better prognosis among the patients with FIGO IA compared to FIGO IB (5-DFS, 97 versus 86%, p = 0.047). Among the risk factors, there were only statistically significant differences in the 5-OS, between the ages of ≤ 70 years and >70 years. Use of brachytherapy may affect the reduction in the number of local recurrences at the vaginal stump (6% versus 2%). This is particularly noticeable in the low-risk subgroup (9% versus 0%).

Radiation-induced vaginal stenosis: current perspectives

Treatment of gynecological cancer commonly involves pelvic radiation therapy (RT) and/or brachytherapy. A commonly observed side effect of such treatment is radiation-induced vaginal stenosis (VS). This review analyzed the incidence, pathogenesis, clinical manifestation(s) and assessment and grading of radiation-induced VS. In addition, risk factors, prevention and treatment options and follow-up schedules are also discussed. The limited available literature on many of these aspects suggests that additional studies are required to more precisely determine the best management strategy of this prevalent group after RT.

American Brachytherapy Task Group Report: Adjuvant vaginal brachytherapy for early-stage endometrial cancer: A comprehensive review

This article aims to review the risk stratification of endometrial cancer, treatment rationale, outcomes, treatment planning, and treatment recommendations of vaginal brachytherapy (VBT) in the postoperative management of endometrial cancer patients. The authors performed a thorough review of the literature and reference pertinent articles pertaining to the aims of this review. Adjuvant VBT for early-stage endometrial cancer patients results in very low rates of vaginal recurrence (0-3.1%) with low rates of late toxicity which are primarily vaginal in nature. Post-Operative Radiation Therapy in Endometrial Cancer 2 (PORTEC-2) supports that VBT results in noninferior rates of vaginal recurrence compared to external beam radiotherapy for the treatment of high-intermediate risk patients. VBT as a boost after external beam radiotherapy, in combination with chemotherapy, and for high-risk histologies have shown excellent results as well though randomized data do not exist supporting VBT boost. There are many different applicators, dose-fractionation schedules, and treatment planning techniques which all result in favorable clinical outcomes and low rates of toxicity. Recommendations have been published by the American Brachytherapy Society and the American Society of Radiation Oncology to help guide practitioners in the use of VBT. Data support that patients and physicians prefer joint decision making regarding the use of VBT, and patients often desire additional treatment for a marginal benefit in risk of recurrence. Discussions regarding adjuvant therapy for endometrial cancer are best performed in a multidisciplinary setting, and patients should be counseled properly regarding the risks and benefits of adjuvant therapy.

A new short daily brachytherapy schedule in postoperative endometrial carcinoma. Preliminary results

PURPOSE

To evaluate the preliminary results of vaginal-cuff relapses (VCR) and complications of a short brachytherapy (BT) schedule in postoperative endometrial carcinoma.

METHODS AND MATERIALS

From September 2011 to December 2014, 102 patients were treated with postoperative BT for endometrial carcinoma. Seventy-four patients received a single 7 Gy dose after external beam irradiation (Group 1), and 28 intermediate-risk patients received three daily fractions of 6 Gy (Group 2). The dose was prescribed at 5 mm from the applicator surface. Toxicity was prospectively evaluated after the objective late effects of normal tissues-subjective, objective, management, analytic scores for vagina and RTOG scores for rectum and bladder.

STATISTICS

χ² and Student's t tests.

RESULTS

The mean followup was 28.85 months (9.6-58.5) in Group 1 and 31.19 months (7.7-62.3) in Group 2. No VCR was found during followup. Late toxicity: vagina toxicity was developed in 24.32% of the patients in Group 1 (G1-G2) and in 21.4% in Group 2 (G1-G2 but 1 G3). Rectal toxicity appeared in only 2.7% of patients in Group 1 (G1). Neither Group 1 nor Group 2 presented late bladder toxicity. No differences were found in late toxicity between Groups 1 and 2.

CONCLUSIONS

The present short BT schedule was safe in relation to VCR and late toxicity for the followup period studied. These results are similar to those of two larger previous schedules performed in our center in relation to the same point of followup.

Treatment outcomes after adjuvant radiotherapy following surgery for patients with stage I endometrial cancer

PURPOSE

The purpose of this study is to evaluate the treatment outcomes of adjuvant radiotherapy using vaginal brachytherapy (VB) with a lower dose per fraction and/or external beam radiotherapy (EBRT) following surgery for patients with stage I endometrial carcinoma.

MATERIALS AND METHODS

The subjects were 43 patients with the International Federation of Gynecology and Obstetrics (FIGO) stage I endometrial cancer who underwent adjuvant radiotherapy following surgery between March 2000 and April 2014. Of these, 25 received postoperative VB alone, while 18 received postoperative EBRT to the whole pelvis; 3 of these were treated with EBRT plus VB. The median EBRT dose was 50.0 Gy (45.0-50.4 Gy) and the VB dose was 24 Gy in 6 fractions. Tumor dose was prescribed at a depth of 5 mm from the cylinder surface and delivered twice per week.

RESULTS

The median follow-up period for all patients was 57 months (range, 9 to 188 months). Five-year disease-free survival (DFS) and overall survival (OS) for all patients were 92.5% and 95.3%, respectively. Adjuvant radiotherapy was performed according to risk factors and stage IB, grade 3 and lymphovascular invasion were observed more frequently in the EBRT group. Five-year DFS for EBRT and VB alone were 88.1% and 96.0%, respectively (p = 0.42), and 5-year OS for EBRT and VB alone were 94.4% and 96%, respectively (p = 0.38). There was no locoregional recurrence in any patient. Two patients who received EBRT and 1 patient who received VB alone developed distant metastatic disease. Two patients who received EBRT had severe complications, one each of grade 3 gastrointestinal complication and pelvic bone insufficiency fracture.

CONCLUSION

Adjuvant radiotherapy achieved high DFS and OS with acceptable toxicity in stage I endometrial cancer. VB (with a lower dose per fraction) may be a viable option for selected patients with early-stage endometrial cancer following surgery.

MRI-Based Evaluation of the Vaginal Cuff in Brachytherapy Planning: Are We Missing the Target?

PURPOSE

Although recurrences and toxicity occur after vaginal cuff (VC) brachytherapy, little is known about dosimetry due to the inability to clearly visualize the VC on computed tomography (CT). T2-weighted (T2W) magnetic resonance imaging (MRI) is superior to CT in this setting, and we hypothesized that it could provide previously unascertainable dosimetric information.

METHODS AND MATERIALS

In a cohort of 32 patients who underwent cylinder-based brachytherapy for endometrial cancer with available MR simulation images, the VC was retrospectively contoured on T2W images, and cases were replanned to treat the upper VC to a dose of 7 Gy/fraction prescribed to 5 mm. Relevant dose-volume parameters for the VC were calculated.

RESULTS

T2W MRI identified significant underdosing not observed on CT or T1-weighted imaging. Over two-thirds (69%) of patients had at least 1 cm(3) of VC that received less than 75% of the prescription dose and half (50%) of patients had a least 1 cm(3) of VC that received less than 50% of the prescription dose. The mean minimum point dose to the VC was 2.4 Gy, or 34% of the intended prescription dose (range: 0.53-6.4 Gy).

CONCLUSIONS

We identified previously unreported VC underdosing in over two-thirds of our patients, with most of these patients having volumes of undistended VC that received less than half of the prescription dose. The maximum dimension was along the craniocaudal axis in some patients or left-right/anterior-posterior axis in others, suggesting that suture material may be restricting access to the vaginal apex and that alternative applicators may be needed when the diameter of the apex is larger than the introitus. Additional follow-up will be needed to determine whether underdosing is associated with isolated VC failure or whether low failure rates across the cohort suggest that some patients are being exposed to excessive dose and unnecessary risk of toxicity.

Vaginal brachytherapy for postoperative endometrial cancer: 2014 Survey of the American Brachytherapy Society

PURPOSE

Report current practice patterns for postoperative endometrial cancer emphasizing vaginal brachytherapy (VBT).

METHODS AND MATERIALS

A 38-item survey was e-mailed to 1,598 American Brachytherapy Society (ABS) members and 4,329 US radiation oncologists in 2014 totaling 5,710 recipients. Responses of practitioners who had delivered VBT in the previous 12 months were included in the analysis. Responses were tabulated to determine relative frequency distributions. χ(2) analysis was used to compare current results with those from the 2003 ABS survey.

RESULTS

A total of 331 respondents initiated the VBT survey, of whom 289 (87.3%) administered VBT in the prior 12 months. Lymph node dissection and number of nodes removed influenced treatment decisions for 90.5% and 69.8%, respectively. High-dose-rate was used by 96.2%. The most common vaginal length treated was 4 cm (31.0%). Three-dimensional planning was used by 83.2% with 73.4% of those for the first fraction only. Doses to normal tissues were reported by 79.8%. About half optimized to the location of dose specification and/or normal tissues. As monotherapy, the most common prescriptions were 7 Gy for three fractions to 0.5-cm depth and 6 Gy for five fractions to the surface. As a boost, the most common prescriptions were 5 Gy for three fractions to 0.5-cm depth and 6 Gy for three fractions to the vaginal surface. Optimization points were placed at the apex and lateral vagina by 73.1%. Secondary quality assurance checks were performed by 98.9%.

CONCLUSIONS

VBT is a common adjuvant therapy for endometrial cancer patients, most commonly with HDR. Fractionation and planning processes are variable but generally align with ABS recommendations.

Predictors of vaginal stenosis after intravaginal high-dose-rate brachytherapy for endometrial carcinoma

PURPOSE

Intravaginal high-dose-rate brachytherapy is an effective adjuvant treatment for localized endometrial carcinoma. However, relatively little is known about risk factors of post-treatment vaginal stenosis (VS).

METHODS AND MATERIALS

We included patients treated with brachytherapy for endometrial carcinoma from September 2011 to January 2014 with at least 3 months of followup. Patients who received external beam radiation therapy were excluded. VS was prospectively graded at each followup visit per Common Terminology Criteria for Adverse Events, version 4.03. χ(2) and t test analyses were used to assess the association of VS with various patient, tumor, treatment, and post-treatment factors. Multivariable logistic regression analysis was used to identify independent predictors of VS Grade ≥1 and ≥2.

RESULTS

All 101 patients were disease free at last followup. Mean followup was 12.9 months (range, 3-34). Highest VS grades were zero in 67%, one in 26%, two in 6%, and three in 1%. Borderline significant variables associated with Grade ≥1 VS included vagina length, proportion of vagina treated, and total dose. Dilator use was significantly associated with Grade ≥2. Multivariable analysis revealed that proportion of vagina treated >60% (odds ratio [OR], 3.48; p = 0.009) and total dose >14 Gy (OR, 4.27; p = 0.015) were independent predictors of Grade ≥1 VS, and lack of consistent dilator use was an independent predictor of Grade ≥2 VS (OR, 5.60; p = 0.047).

CONCLUSIONS

Patients treated with a higher total dose to a larger proportion of the vagina were more likely to develop Grade ≥1 VS. Consistent dilator use may also be protective against Grade ≥2 VS.

A novel intracavitary applicator design for the treatment of deep vaginal fornices: preliminary dose metrics and geometric analysis

Purpose

To investigate the dose distributions associated with a novel balloon sleeve placed over a standard cylinder applicator.

Material and methods

A computed tomography (CT) scan of a sleeve balloon shaped to inflate into the vaginal fornices was used to digitize 1-, 3-, and 5-catheter configurations. Point doses for rectum, apex, and fornix were calculated and compared to the values associated with a standard cylinder plan not targeting the vaginal fornices. Inflation of the sleeve balloon in the vaginal fornices and dose coverage with constraints to the rectum, bladder, and sigmoid D_2cc were evaluated.

Results

Rectum, apex, and fornix doses were respectively 76%, 119%, and 44% for a standard cylinder; 190%, 310%, and 93% for a 1-catheter configuration; 98%, 109%, and 109% for a 3-catheter configuration; and 91%, 107%, and 96% for the 5-catheter configuration. In a patient analysis, expansion of the sleeve balloon into the vaginal fornices was confirmed. The 5-catheter configurations were associated with best coverage of the fornices and acceptable doses to rectum, bladder, and sigmoid.

Conclusions

A 1-catheter configuration cannot be used clinically due to high rectal and apex dose. In theoretical analysis, the 3- and 5-catheter configurations showed > 96% coverage to the vaginal fornices with a clinically acceptable rectal dose. In a treatment simulation in a patient, a 5-catheter configuration showed 90% coverage of the fornices with acceptable doses to the organs at risk. The treatment of deep vaginal fornices results in an increased rectal dose compared to a standard cylinder plan.

Postoperative brachytherapy for endometrial cancer using a ring applicator

BACKGROUND

To evaluate the rate of vaginal, pelvic, and distant failures and acute toxicity after postoperative vaginal vault brachytherapy (VBT) delivered by a ring applicator in women with high intermediate-risk endometrial cancer.

METHODS AND MATERIALS

A total of 100 patients were treated with VBT after a total abdominal hysterectomy and bilateral salpingo-oophorectomy for a Stage IA or IB (International Federation of Gynecology and Obstetrics 2009) intermediate-risk endometrial cancer; 26 patients received 30-Gy low-dose-rate, 74 patients received 28-Gy pulsed-dose-rate brachytherapy.

RESULTS

At a median followup of 37 months (range, 1-107), 6 (6%) patients showed failures. Three patients developed an in-field recurrence in the vaginal vault: 1 was isolate, whereas the other 2 showed simultaneous pelvic and/or distant failure. A fourth patient developed an out-of-field recurrence in the posterior vaginal wall of the proximal half of the vagina, including pelvic and distant failure. Two other patients showed only distant failure. The estimated 3-year actuarial rate of any vaginal recurrence was 2.6% (95% confidence interval, 0-6.3%). The 5-year overall survival was 84%, similar to that in the female Dutch population matched for age and date of diagnosis. The acute side effects were low, consisting mainly of the occurrence of temporary diarrhea (2%).

CONCLUSION

Postoperative VBT by a ring applicator results in a low recurrence risk, survival rates comparable with the normal female population, and a very low risk of acute morbidity.

Early recurrence of early stage endometrioid endometrial carcinoma: possible etiologic pathways and management options

The majority of endometrial cancers is early stage and of the endometrioid histological type, as the symptoms (mainly vaginal bleeding) of the disease lead to an early diagnosis. Close follow-up is nevertheless essential in such cancers staged early on, in which the rate of recurrence is relatively low. We retrieved the studies included in our narrative review after performing a systematic electronic search in the PubMed, Scopus and Cochrane databases. The incidence or recurrence of disease in such patients could be up to 2.6%, with the main sites of recurrence being the vaginal vault or metastases in distant parts of the body. Genetic factors such as p53 overexpression, inactivation of 14-3-3-sigma, KRAS amplification and KRAS mRNA expression, microsatellite instability and Lynch syndrome genes could be associated with such a recurrence. Black race is also correlated, as well as lymphovascular space involvement, lower uterine segment involvement and DNA aneuploidy. Longer hysteroscopy duration was not found to be associated. Close follow-up is suggested for early detection of recurrences, while surgical excision of isolated disease or exenteration of local disease as well as radiotherapy and chemotherapy are the main treatment options. This narrative review investigated the possible mechanisms of early recurrence in patients with endometrioid endometrial cancer as well as the further management of them.