Chemotherapy Plus Radiotherapy Not Superior to Radiotherapy Alone in Improving Survival for Patients With High-Risk Endometrial Cancer
Women with high-risk endometrial cancer (EC) are at an increased risk of metastasis and death. The randomized, intergroup PORTEC-3 study assessed the benefit of adjuvant chemotherapy during and after radiotherapy (RT) versus pelvic RT alone in this patient population. The researchers presented the study at the ASCO Annual Meeting (http://abstracts.asco.org/199/AbstView_199_180760.html).
A total of 660 women with high-risk EC (defined as Federation of Gynecology and Obstetrics stage I, grade 3 with deep myometrial invasion and/or lymphovascular space invasion; stage II or III; or serous/clear cell histology) were randomized 1:1 based on participating center, lymphadenectomy, stage, and histologic type to receive RT alone (48.6 Gy in 1.8 Gy fractions; n = 330) or chemotherapy plus RT (two cycles of cisplatin 50 mg/m² in week 1 and four cycles of RT, followed by four cycles of carboplatin area under the curve = 5 and paclitaxel 175 mg/m² at three-week intervals; n = 330). Patients were enrolled between 2006 and 2013, for a median follow-up of 60.2 months (range = 47.1–72.9).
Three-year overall survival ([OS], a co-primary endpoint) was 84.4% for those treated with chemotherapy and RT compared to 83.9% for those treated with RT alone, whereas five-year OS was 81.8% and 76.7%, respectively (overall hazard ratio [HR] = 0.79; 95% CI, 0.57–1.12; p = 0.183).
Three-year failure-free survival ([FFS], a co-primary endpoint) was 79.7% for those treated with chemotherapy and RT compared to 71.8% for those treated with RT alone, whereas five-year FFS was 75.5% and 68.9%, respectively (overall HR = 0.77; 95% CI = 0.58–1.03; p = 0.078).
Patients with stage III EC had lower five-year FFS (63.9% versus 78.9%; p < 0.001) and OS (74.3% versus 83.1%; p = 0.003) compared to those with stage I or II. Patients with stage III disease also had the greatest benefit of chemotherapy plus RT: five-year FFS was 69.3% compared to 58.0% for RT alone (95% CI = 0.45–0.97, p = 0.032), and five-year OS for 78.7% versus 69.8%, respectively (p = 0.114).
“Adjuvant chemotherapy given during and after pelvic RT for treatment of high-risk EC did not significantly improve five-year FFS and OS compared with RT alone,” the authors concluded. “For women with stage III EC, FFS was, however, significantly improved with chemotherapy plus RT by 11% at five years.”
The researchers are continuing long-term follow-up of this study.