Final analysis of RTOG 9708: adjuvant postoperative irradiation combined with cisplatin/paclitaxel chemotherapy following surgery for patients with high-risk endometrial cancer.

PURPOSE: A phase II study was completed by the RTOG to assess the feasibility, safety, toxicity, and patterns of recurrence and survival when chemotherapy was combined with adjuvant radiation for patients with high-risk endometrial cancer.
MATERIALS AND METHODS: Pathologic requirements included grade 2 or 3 endometrial adenocarcinoma with either >50% myometrial invasion, cervical stromal invasion, or pelvic-confined extrauterine disease. Radiation included 45 Gy in 25 fractions to the pelvis along with cisplatin (50 mg/m(2)) on days 1 and 28. Vaginal brachytherapy was performed after the external beam radiation. Four courses of cisplatin (50 mg/m(2)) and paclitaxel (175 mg/m(2)) were given at 4-week intervals following completion of radiotherapy.
RESULTS: Forty-six patients were entered between 10/97 and 4/99. Follow-up times range from 6.8 to 72 months with a median of 4.3 years. Maximum late toxicity was grade 1 in 16%, grade 2 in 41%, grade 3 in 16%, and grade 4 in 5%. At 4 years pelvic, regional and distant recurrence rates are 2%, 2%, and 19%, respectively. Overall survival and disease-free survival (DFS) rates at 4 years are 85% and 81%, respectively. Four-year rates for survival and DFS for Stage III patients are 77% and 72%, respectively. There have been no recurrences for patients with stage IC, IIA, or IIB.
CONCLUSION: Local-regional control is excellent following combined modality treatment in all patients suggesting additive effects of chemotherapy and radiation. Distant metastases continue to occur in more advanced staged patients. This regimen appears reasonable to be tested for efficacy in randomized studies.