Long-term outcomes using adjuvant pelvic intensity modulated radiation therapy (IMRT) for endometrial carcinoma

We evaluated the long-term outcome and toxicity of adjuvant intensity modulated radiation therapy (IMRT) for high-risk endometrial carcinoma via a retrospective institutional review of patients treated in this setting with extended follow-up.

Patients with endometrial cancer who underwent comprehensive surgical staging followed by adjuvant IMRT with or without sequential chemotherapy between 1999 and 2010 were reviewed. Median doses delivered with IMRT and brachytherapy were 45 Gy in 25 fractions and 10 Gy in 2 fractions; 10.2% received extended field and 94.5% received vaginal brachytherapy. Kaplan-Meier estimates are provided for rates of locoregional (in-field) relapse, distant metastasis, and disease-free survival, and overall survival. Gastrointestinal (GI) and genitourinary (GU) toxicity reported were graded with the Common Terminology Criteria for Adverse Events, version 4.03.

A total of 128 patients were identified. Median age at diagnosis was 64 years. Most patients (82.8%) had endometrioid adenocarcinoma followed by papillary serous (10.2%), clear cell (4.7%), and carcinosarcoma (2.3%). International Federation of Gynecology and Obstetrics staging distribution was as follows: IA, 13.3%; IB, 32.8%; II, 30.4%; IIIA, 5.5%; IIIC1, 9.4%; and IIIC2, 8.6%. Most (85.9%) underwent nodal dissections (28.1% pelvic only and 57.8% pelvic and para-aortic). Two patients (1.6%) experienced acute grade 3 GI toxicity; no other acute grade ≥3 GI/GU toxicities were noted. With a median follow-up of 57.0 months, 5-year locoregional relapse was 2.5%: vagina (n = 3), parametrium (n = 1), pelvic node (n = 1). Five-year estimates of distant metastasis, disease-free survival, and overall survival were 16.5%, 73.4%, and 77.4%, respectively. Five-year actuarial rates of late grade 3 GI and GU toxicities were 3.2% and 0.0%. The 5-year rate of symptomatic pelvic insufficiency fracture was 4.4%.

This study represents the largest cohort of endometrial cancer patients with extended follow-up receiving adjuvant IMRT. High rates of pelvic disease control and limited late toxicities demonstrate safety and efficacy of this approach in the setting of extended follow-up.