RT Journal Article SR Electronic T1 EP401 Ureter delineation and dose reporting in image guided brachytherapy for cervical cancer JF International Journal of Gynecologic Cancer JO Int J Gynecol Cancer FD BMJ Publishing Group Ltd SP A266 OP A266 DO 10.1136/ijgc-2019-ESGO.460 VO 29 IS Suppl 4 A1 Sarwar, A A1 Lalli, N A1 Eminowicz, G YR 2019 UL http://ijgc.bmj.com/content/29/Suppl_4/A266.2.abstract AB Introduction/Background Ureteric stenosis is a severe complication of pelvic radiotherapy and brachytherapy in patients with locally advanced cervical cancer. Ureter delineation and subsequent dose reporting is not routinely performed. Therefore, the dose-response relationship is not fully understood.Methodology A retrospective analysis of 100 cervical cancer patients treated with image guided brachytherapy between January 2014 and March 2019 was performed. All patients received a brachytherapy dose of 21 Gray (Gy)/3 fractions (#) after concurrent chemo-radiotherapy (50.4 Gy/28#). Bilateral ureters were delineated with the aid of a consultant radiologist. Maximum dose to 2cc (D2cc) and 0.1cc (D0.1cc) to right and left ureters were recorded for the first brachytherapy treatment and extrapolated for the remaining two fractions. Total ureter dose for the course of treatment was calculated. Ureteric toxicity was recorded and graded according to CTCAE v4.03.Results Of the 100 patients treated, 71 had FIGO stage 2B disease, the remainder ranged from stage 1A2 to 4A; 77% were squamous cell carcinomas. Median follow-up was 32 months. Mean (range) right and left ureter D0.1cc were 79.7 Gy (56.8–138) and 77.8 Gy (52.6–114) respectively. Mean (range) right and left ureter D2cc were 53.3 Gy (52.6–60.5) and 53.4 Gy (52.6–59.2) respectively. 5 (5%) patients experienced ureteric stenosis. 2 (2%), 1 (1%), 1 (1%) and 1 (1%) were grade 1 (G1), G2, G3 and G4 respectively. Further correlation analyses will be performed.Conclusion Image guided brachytherapy is the gold standard of treatment for locally advanced cervical cancer. There is limited data on the dose of radiotherapy the ureters are exposed to during a course of radical radiotherapy. Rates of ureteric stenosis were in keeping with published data. Delineation of ureters is possible and can be done with minimal training adding little additional time to the contouring process.Disclosure Nothing to disclose.