Sequencing chemotherapy before radiotherapy for women with stage IIIC endometrial cancer

It is unclear how to best sequence adjuvant chemotherapy and radiotherapy for advanced endometrial cancer. We studied the outcomes for women treated with chemotherapy before radiotherapy in a chemotherapy-first (chemotherapy for 6 cycles followed radiotherapy) or 'sandwich' approach (chemotherapy for 3 cycles followed by radiotherapy and subsequently chemotherapy for 3 cycles).

Women with stage IIIC endometrial cancer and no gross residual disease treated with chemotherapy before radiotherapy between April 2003 and April 2016 were included. The Kaplan-Meier method was used to estimate recurrence and survival. We performed a meta-analysis of endometrial cancer trials comparing chemotherapy and radiotherapy versus radiotherapy alone.

A total of 102 patients were included. The mean (SD) age was 63.8 (10.6) years; 84 patients received the chemotherapy-first approach and 18 patients received the 'sandwich' approach. Pelvic and para-aortic nodes were removed in 99% and 88.2%, respectively. Among all the patients, we observed 1 pelvic (1%), 1 para-aortic (1%), and 5 vaginal (4.9%) recurrences. At 3 years, for the 'sandwich' and chemotherapy-first approaches, the vaginal recurrence was 11.8% and 4.2%, pelvic recurrence was 0% and 1.5%, para-aortic recurrence was 0% and 1.2%, distant recurrence was 42.9% and 24.4%, and overall survival was 70.3% and 81.7%, respectively. With 'chemotherapy before radiotherapy' 94.9% completed 4+ chemotherapy cycles (vs 71-90% reported in the literature for 'radiotherapy before chemotherapy'). In a meta-analysis of endometrial cancer trials, distant recurrence rates were reduced with 4+ chemotherapy cycles but not with 3 cycles (p=0.01).

Chemotherapy before radiation sequencing for stage IIIC endometrial cancer was associated with a high proportion of patients completing 4+ chemotherapy cycles and low locoregional lymphatic recurrence rate, despite delaying radiotherapy until after 3-6 cycles of chemotherapy and not administering concurrent cisplatin.