A randomized phase-III study on adjuvant treatment with radiation (RT) ± chemotherapy (CT) in early-stage high-risk endometrial cancer (NSGO-EC-9501/EORTC 55991)
5503 Background: Adjuvant therapy for early stage high-risk endometrial cancer remains controversial. Methods: Patients with surgical stage I, II, IIIA (positive peritoneal fluid cytology only), or IIIC (positive pelvic lymph nodes only) were eligible if they, according to departmental guidelines, had a sufficiently high risk for micrometastatic disease to qualify for adjuvant therapy. Most patients had two or more of the risk factors: grade 3, deep myometrial invasion, or DNA non-diploidy, while some patients had only one of these. Patients with serous, clear cell, or anaplastic carcinomas were eligible regardless of risk factors. Patients with para-aortic metastases were not eligible. Lymph node exploration at staging surgery was optional. Pelvic RT ± vaginal brachytherapy was given to a dose =44 Gy. CT was given before or after RT. Before August 2004 CT consisted of four courses of cisplatin =50 mg/m2 + doxorubicin 50 mg/m2 or epirubicin 75 mg/m2 (AP). Thereafter several CT regimens were allowed, of which AP, paclitaxel 175 mg/m2 + epirubicin 60 mg/m2 + carboplatin AUC 5, and paclitaxel 175 mg/m2 + carboplatin AUC 5–6 were used. Progression-free survival (PFS) was the primary end-point. The study was terminated before the aimed goal of 400 patients because of slow recruitment. We decided to make an early analysis since new studies on endometrial cancer are presently discussed. Results: 372 patients were entered between May 1996 and Oct 2006. Of 367 evaluable patients 190 were randomized to RT and 177 to RT+CT. Risk factors were well balanced between the randomization arms. The median follow-up time was 3.5 years. The hazard ratio for PFS was 0.58 in favor of RT+CT (95 % confidence interval (CI) 0.34 - 0.99; p=0.046). This translates to an estimated 7 % absolute difference in 5-year PFS from 75 % (95 % CI 67 % - 82 %) to 82 % (95 % CI 73 % - 88 %). Conclusion: RT+CT was better than RT alone. Next question is if RT+CT is better than CT alone. No significant financial relationships to disclose.