EQD2 Analyses of Vaginal Complications in Exclusive Brachytherapy for Postoperative Endometrial Carcinoma

SIMPLE SUMMARY: Vaginal complications in exclusive vaginal-cuff brachytherapy (EVCBT) have not been analyzed in terms of the dose received by a vaginal volume of 2 cm(3). The aim of this work was to analyze the vaginal dose and complications in EVCBT. In the present analysis, we found that all the patients receiving < 68Gy equivalent dose 2Gy/day at 2 cm(3) of the most exposed area to the dose of the vagina only developed G0–G1 and 1G2 without vaginal stenosis complications and without relapses. This dose limit could eliminate G2 vaginal stenosis and is the hypothesis of a new analysis in our center. ABSTRACT: Background: To evaluate whether EQD2((α/β = 3Gy)) at 2 cm(3) of the most exposed area of the vagina is related to late vaginal toxicity in postoperative endometrial cancer (PEC) patients (p) treated with exclusive brachytherapy (BT). Methods: From 2014 to 2017, 43p were included in this study. BT was administered: 3-fractions of 6Gy in 37p and 2-fractions of 7.5Gy in 6p. The dose was prescribed at a depth of 5 mm from the applicator surface with dose-point optimization based on distance. The active treatment length was 2.5 cm. CTV-D90 and the dose to the most exposed 2 cm(3) of the vagina was calculated for each patient. Late toxicity of the bladder and rectum was assessed using Radiation Therapy Oncology Group (RTOG) criteria, and vaginal toxicity by objective Late Effects Normal Tissue Task Force (LENT)-Subjective, Objective, Management, Analytic (SOMA) (LENT-SOMA) criteria. Statistics: frequency tables, mean, median, range, standard deviation, and box plot. Results: The median follow-up was 51 months (12–68). 20 p (46.5%) and 2 p (4.7%) developed G1 and G2 vaginal complications, respectively. Only 1/2 p-G2 receiving EQD2((α/β = 3Gy)) at 2 cm(3) >68Gy presented vaginal shortening and 18/20 p-G1 received doses < 68Gy. Conclusions: PECp receiving exclusive brachytherapy with doses < 68Gy EQD2((α/β = 3Gy)) at 2 cm(2) of the vagina presented only G0–G1 vaginal toxicity, except for one with bleeding telangiectasias. Larger prospective studies are necessary to confirm the present results.