Effects of vaginal cylinder position on dose distribution in patients with endometrial carcinoma in treatment of vaginal cuff brachytherapy

Gastrointestinal and genitourinary toxicity following high dose rate vaginal cuff brachytherapy for endometrial cancer

PURPOSE

There are currently no organs at risk dose constraints for adjuvant HDR vaginal cuff brachytherapy (VBT). This study evaluates OAR dosimetry and the association with acute and chronic gastrointestinal (GI) or genitourinary (GU) toxicity.

METHODS

Patients treated at a single institution with VBT of 21 Gray (Gy) in 3 fractions (Fx) prescribed to 5 mm depth twice weekly and CT-based 3D planning were reviewed. OAR doses (D2cc, D1cc, and D0.1cc) were recorded. Acute and chronic toxicities were graded by Common Terminology Criteria for Adverse Events v5.0. Boxplot and Wilcoxon-Mann-Whitney tests compared dose thresholds.

RESULTS

177 patients with stage I-IV endometrial cancer received a mean D2cc to rectum, sigmoid, small bowel, and bladder of 5.7 Gy (range: 2.8-8.7), 3.3 Gy (0.6-9.3), 3.8 Gy (0.0-9.1), and 5.4 Gy (2.0-8.2). Overall, 6.2% (n = 11) and 7.3% (n = 13) of patients experienced acute GI and GU toxicity of any grade. 14.7% (n = 26) and 14.7% (n = 26) of patients experienced chronic GI and GU toxicity of any grade, respectively. There were two grade 3 toxicities include one chronic GI and one acute GU. No dosimetric factors were identified that correlated with a higher likelihood of acute or chronic toxicity.

CONCLUSIONS

The overall rate of GI and GU toxicity following VBT of 21 Gy in 3 Fx is low, and there are no dosimetric parameters that correlate with toxicity. The optimal dose fractionation schedule that balances high local control with minimal toxicity is yet to be determined.

Isolated vaginal recurrence in women with stage I endometrial cancer

OBJECTIVE

To compare clinical and pathologic characteristics of women with surgical stage I endometrial carcinoma by location of first recurrence and describe characteristics of isolated vaginal recurrence.

METHODS

Patients with 2009 International Federation of Obstetrics and Gynecology (FIGO) stage I endometrial carcinoma treated at two large cancer centers from 1/1/2009-12/31/2017 were identified. Sarcoma histology was excluded. Recurrences were grouped into isolated vaginal or extravaginal. Isolated vaginal recurrences were localized by anatomic location within the vaginal vault. Clinical and pathologic variables were compared with chi-square analysis, and Kaplan-Meier curves with log-rank tests.

RESULTS

Of 2815 women identified, 278 (10%) experienced a recurrence. Sixty-one patients (2%) had an isolated vaginal recurrence, including 42 (69%) at the vaginal apex; 217 (8%) had an extravaginal recurrence, including 18 with a vaginal component. Median time to recurrence was 11 months (range, 1-68) for isolated vaginal recurrence and 20 months (range, 1-98) for extravaginal recurrence (P < .004). Of 960 patients (34%) treated with adjuvant vaginal brachytherapy (VBT), 156 (16%) recurred; 19 (2%) had an isolated vaginal recurrence, including 16 (84%) at the vaginal apex. Three-year PFS rates for isolated vaginal recurrence were 97.6% (SE ± 0.4%) with minimally invasive surgery (MIS) versus 96.9% (SE ± 1.1%) with open (P = .8), and for extravaginal recurrence were 91.8% (SE ± 0.7%) with MIS versus 90.8% (SE ± 1.8%) with open (P = .8).

CONCLUSIONS

Isolated vaginal recurrences in stage I endometrial cancer are detected earlier than non-vaginal recurrences. Surgical approach does not appear to impact recurrence. Adjuvant VBT after primary surgery carries a 1%-2% risk of isolated vaginal apex recurrence.

Applicators used for vaginal high dose rate brachytherapy: Effect of type and shape on dose distribution and toxicity, a literature review

The aim of this article is to represent a literature review on the applicators used for vaginal high dose rate brachytherapy for patients with endometrial cancer. The different types and shapes of the clinically used applicator as well as the effects of their characteristics on dose distribution, target coverage and dose received by organs at risk are discussed in detail.

A novel use of 3D-printed template in vaginal HDR brachytherapy

PURPOSE

The High-Dose-Rate (HDR) vaginal cylinder treatment is typically designed using the initial CT, while the subsequent implants are verified using rudimentary methods (i.e., visual inspection, ruler measurements, etc.) and/or X-ray imaging. We are proposing the use of a 3D-printed individualized template that could provide simple and reproducible vaginal cylinder insertion.

MATERIAL AND METHODS

Six patients were included in the study with prescriptions of 6 Gy/fraction for 2 to 5 fractions (total 27 treatments). The first 1 to 2 treatments were delivered without the template and the rest with the CT-based 3D-printed templates. Cone beam CTs (CBCTs) were acquired to verify the cylinder placement for all treatments. D_2cc of the bladder and rectum are recorded on both planning CT and the following on-treatment CBCTs.

RESULTS

By using the templates, the tip position variation on average (±1 SD) reduced from 0.8±0.5 cm to 0.6±0.4 cm, and angular difference decreased from 5.3±3.5° to 4.7±2.4°. The pitch and yaw deviation are reduced from 0.9 ± 5.8° and 0.4±2.9° to 0.0±3.9° and -0.2±3.0°, respectively. The deviation of D_2cc to bladder from the plan reduced from 6±4% to 5±3%, and rectum from 5±2% to 4±4%.

CONCLUSION

The 3D-printed patient-specific cylinder templates could potentially improve the geometrical reproducibility of cylinder treatments at no cost of additional imaging. The D_2cc for the bladder and rectum are determined by the treatment length rather than their respective volumes.

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.

Vaginal cuff brachytherapy practice in endometrial cancer patients: a report from the Turkish Oncology Group

Purpose

The American Brachytherapy Association is attempting to develop standards for delivering brachytherapy, although differences in practice have been reported in the literature. This study evaluated vaginal cuff brachytherapy (VBT) practice and quality of life-related recommendations among Turkish radiation oncologists.

Material and methods

A nationwide web-based 17-item survey was distributed to the members of the Turkish Society for Radiation Oncology. These members received e-mail notifications, and a link was posted on the Turkish Society for Radiation Oncology internet site to solicit voluntary responses The survey addressed the simulation processes, target volume, prescribed dose, delivery schedules, and recommendations related to vaginal side effects.

Results

Fifty-seven radiation oncologists responded to the survey. The most used dose fraction schemes for adjuvant VBT were 7 Gy × 3 fractions (30%), 5.5 Gy × 5 fractions (26%), and 6 Gy × 5 fractions (28%). The preferred VBT scheme was 5 Gy × 3 fractions (50%) when the external beam radiotherapy (EBRT) dose was 45 Gy external radiotherapy, while the preferred schemes were 6 Gy × 3 fractions (30%) or 5 Gy × 3 fractions (32%) when the external radiotherapy dose was increased to 50.4 Gy. One-half of the respondents delivered VBT twice a week, and the dose was prescribed to 0.5 cm from vaginal mucosa by 86% of the respondents. There was no common definition for the dose prescription length, which was defined as 3 cm from the vaginal cuff in 33% of responses and as 4 cm in 35% of responses. For serous and clear cell histological types, 38% of the respondents targeted "full cylinder length". To prevent vaginal side effects, 78% of the respondents recommended using a vaginal dilator and/or sexual intercourse after VBT.

Conclusions

This survey revealed variations in the clinical practice of VBT among Turkish radiation oncologists, which suggests that standardization is necessary.

Vaginal toxicity after high-dose-rate endovaginal brachytherapy: 20 years of results

Purpose

To evaluate vaginal toxicity (primary endpoint) and local control (secondary endpoint) in patients with endometrial cancer who underwent primary surgery and adjuvant high-dose-rate (HDR) endovaginal brachytherapy (BT).

Material and methods

In September 2017, the authors conducted a comprehensive literature search of the following electronic databases: PubMed, Web of Science, Scopus, and Cochrane library. In this systematic review, the authors included randomized trials, non-randomized trials, prospective studies, retrospective studies, and cases. The time period of the research included articles published from September 1997 to September 2017.

Results

Acute endovaginal toxicity occurred in less than 20.6% and all acute toxicities were G1-G2. The most common early side effects due to HDR-BT treatment were vaginal inflammation, vaginal irritation, dryness, discharge, soreness, swelling, and fungal infection. G1-G2 late toxicity occurred in less than 27.7%. Finally, G3-G4 late vaginal occurred in less than 2%. The most common late side effects consisted of vaginal discharge, dryness, itching, bleeding, fibrosis, telangiectasias, stenosis, short or narrow vagina, and dyspareunia.

Conclusions

The data suggest that HDR endovaginal brachytherapy, with or without chemotherapy, is very well tolerated with low rates of acute and late vaginal toxicities. Further prospective studies with higher numbers of patients and longer follow-up are necessary to evaluate acute and late toxicities after HDR endovaginal brachytherapy.