Introduction/Background The management of endometrial cancer consists of surgery followed by tailored adjuvant therapy but there is a risk of pelvic and/or systemic recurrence. Here, we evaluated the frequency and site of first relapse in patients who received vaginal brachytherapy (± chemotherapy) for FIGO Stage I-II endometrial cancer and stratified retrospectively according to ESGO/ESTRO/ESP 2020 risk classification.

Methodology The central radiotherapy prescribing system at our institution was interrogated to identify patients who commenced vaginal brachytherapy, 2100cGy/3#, for endometrial cancer between 1st January 2017 and 31st December 2019. Only those with Stage I-II disease were included. Clinical follow up was undertaken until death or 5 years had elapsed (data lock 31st December 2022). Imaging was performed if recurrence was suspected.

Results In total, 258 patients were identified. The median age was 69 years (range 40–90) and median follow up was 33 months (range 0–68). FIGO 2018 Stage distribution: IA (35%); IB (48%); II (17%). Pathology subtype: endometrioid (73%); serous (15%); carcinosarcoma (5%); other (7%). ESGO/ESTRO/ESP risk group distribution: Intermediate (43%); High-intermediate (HIR) (39%); High (18%). Adjuvant chemotherapy was delivered to 8.5% of the cohort. By study end, 50 (19%) patients had relapsed and 43 (16%) had died. Frequency of recurrence per risk group: Intermediate 13/112 (11.6%); HIR 17/100 (17%); High 20/57 (35%). Pattern of relapse was as follows: vagina only - 3 (1.1%); pelvis only - 22 (8.5%); distant only - 6 (2.3%); both pelvis and distant – 22 (8.5%). Frequency of pelvic relapse per risk group was Intermediate 11/112 (9.8%), HIR 16/100 (16%), and High 17/57 (29.8%), respectively. Overall pelvic failure rate was 17%.

Conclusion Isolated vaginal relapse rates were very low but pelvic recurrences occurred in up to 15–30% of HIR/High risk patients suggesting that external beam radiotherapy should be considered to optimise loco-regional control in these risk groups.

Disclosures None