The optimal adjuvant therapy for International Federation of Gynecology and Obstetrics (FIGO) stage I papillary serous (UPSC) or clear cell (CC) endometrial cancer is unknown. We report on the largest single-institution experience using adjuvant high-dose-rate vaginal brachytherapy (VBT) for surgically staged women with FIGO stage I UPSC or CC endometrial cancer.

From 1998-2011, 103 women with FIGO 2009 stage I UPSC (n=74), CC (n=21), or mixed UPSC/CC (n=8) endometrial cancer underwent total abdominal hysterectomy with bilateral salpingo-oophorectomy followed by adjuvant high-dose-rate VBT. Nearly all patients (n=98, 95%) also underwent extended lymph node dissection of pelvic and paraortic lymph nodes. All VBT was performed with a vaginal cylinder, treating to a dose of 2100 cGy in 3 fractions. Thirty-five patients (34%) also received adjuvant chemotherapy.

At a median follow-up time of 36 months (range, 1-146 months), 2 patients had experienced vaginal recurrence, and the 5-year Kaplan Meier estimate of vaginal recurrence was 3%. The rates of isolated pelvic recurrence, locoregional recurrence (vaginal+pelvic), and extrapelvic recurrence (including intraabdominal) were similarly low, with 5-year Kaplan-Meier estimates of 4%, 7%, and 10%, respectively. The estimated 5-year overall survival was 84%. On univariate analysis, delivery of chemotherapy did not affect recurrence or survival.

VBT is effective at preventing vaginal relapse in women with surgical stage I UPSC or CC endometrial cancer. In this cohort of patients who underwent comprehensive surgical staging, the risk of isolated pelvic or extrapelvic relapse was low, implying that more extensive adjuvant radiation therapy is likely unnecessary.