1002P - The Role of Intravaginal Brachytherapy in Surgically-Staged 1988 Figo Stage IC Grade 3 Endometrial Cancer

Abstract

ABSTRACT Purpose/objectives Patients with 1988 International Federation of Gynecology and Obstetrics (FIGO) Stage IC grade 3 (ICgr3) endometrial cancer (EC) were excluded or underrepresented on practice-defining intermediate-risk EC trials due to relatively high rates of occult nodal and/or distant metastasis. Adjuvant therapy recommendations in this population vary widely, but standard practice is to offer adjuvant pelvic external beam radiotherapy (EBRT) +/- chemotherapy. We report our single-institution's experience using adjuvant high-dose rate (HDR) vaginal brachytherapy (VBT) alone +/- chemotherapy for patients with surgically-staged 1988 FIGO ICgr3 EC. Methods From 1998 to 2011, 47 women with FIGO ICgr3 EC underwent TAH/BSO with pelvic/paraaortic lymph node dissection (median nodes evaluated, 47; range, 5-88) followed by VBT. All VBT was performed using a multi-channel cylinder, treating the entire vaginal mucosa from the cuff to within 1-2 cm of urethral meatus to 21 Gy in 3 fractions. No patient received pelvic EBRT. Twenty-one patients (45%) also received 3 to 6 cycles of adjuvant platinum-based chemotherapy. Results At a median follow-up of 30 months (range, 1 to 127 months), 3 patients had experienced a vaginal relapse (VR), and the 3-year Kaplan-Meier (KM) estimate of VR was 8%. Rates of isolated pelvic (PR), locoregional (LRR, VR + PR), and distant relapse (DR) were similarly low, with 3-year estimates of 3, 10, and 14%, respectively. Estimates for 3-year disease-free (DFS) and overall survival (OS) were 87 and 80%, respectively. On univariate analysis, administration of chemotherapy significantly correlated with improved DFS (p = 0.03). Conclusions Rates of isolated vaginal and pelvic relapse after VBT +/- chemotherapy in these women with surgically-staged 1988 FIGO ICgr3 EC were comparable to those seen with pelvic EBRT, implying additional radiotherapy is likely unnecessary. Adjuvant platinum-based chemotherapy was associated with improved disease-free survival. While VBT reduced the rate of pelvic relapse, the vagina remained the most common pelvic site of recurrence. Disclosure All authors have declared no conflicts of interest.