Pilot Study to Assess the Change in Vaginal Dimensions Following Vaginal Brachytherapy (VBT).

Purpose/objective(s) Toxicities related to vaginal brachytherapy can be challenging to capture in patients with endometrial cancer treated with VBT HDR. In this pilot study, we sought to objectively measure the changes in vaginal length and caliber while capturing patient reported acute and chronic toxicities. Materials/methods 63 patients with endometrial carcinoma treated with VBT 30 Gy in 3 fractions to the vaginal surface using Ir192 HDR from March 2015 through December 2018 were invited to return for a research visit. 18 patients with AJCC 8th pT1-T2 pNx-N1 cM0 endometrial carcinoma returned to clinic for measurement of vaginal length and diameter using VBT cylinders. Measurements were compared to vaginal length/diameter assessed during the first brachytherapy treatment. Vaginal and vulvar atrophy were assessed. Pain during insertion was measured on a scale of 0 to 10. The patients completed questionnaires regarding vaginal, rectal, urinary and dermatologic toxicities (using CTCAE v5.0). Toxicities were classified as acute if they occurred within the first 2 months after treatment, or chronic if they occurred 2 months after treatment. The mean differences in change between start of VBT and research visit for both vaginal length and diameter were calculated. Results Median age at time of diagnosis was 69 years (range 46-88). Tumor stage was pT1a 50% (n = 9), pT1b 38.9% (n = 7), and pT2 11.1% (n = 2). Of the 18, 13 (72.2%) had endometrioid tumors, 2 (11.1%) had serous, 2 (11.1%) had mixed, and 1 (5.6%) had clear cell. Median length of time from VBT start until research visit was 43.3 months. The median original vaginal length of the 18 women was 13.9 cm (range 11 - 18 cm). The median original cylinder size was 3.0 cm (range 2.5-3.0 cm). The mean decrease in vaginal length from VBT start to visit date was 1.4 cm, which was significantly different from zero (P = 0.0002). The mean decrease for the vaginal diameter was 0.03 cm which was not significantly different from zero (P = 0.6). On exam, 12 (66.6%) had grade 1-2 vaginal atrophy and 5 (27.8%) had grade 1 vulvar atrophy. Pain during cylinder placement was median of 1 (range 0-10); 77.8% had 0-2 out of 10 pain. Patient-reported acute grade 1-2 toxicities included dermatitis (n = 1), and cystitis (n = 1). There were no patient-reported grade 3-5 acute or chronic toxicities. Patient-reported chronic grade 1-2 toxicities included cystitis (n = 2), vaginal stenosis (n = 2), and diarrhea (n = 1). Conclusion In our pilot study of 18 patients treated with VBT with 30 Gy in 3 fractions to the vaginal surface, we found a statistically significant average vaginal shortening after approximately 4.5 years of average follow-up. We observed no significant change in vaginal diameter. VBT was followed by infrequent patient-reported grade 1-2 acute or chronic toxicities. This report adds to the scarce literature of objective data on vaginal sequelae of VBT for endometrial carcinoma. Author disclosure K. Nieto: None. B. Levine: None. D.R. Brown: None. H.S. McGinnis: None. C.M. Lanier: None. K. Hines: None. K.M. Greven: None.