Applicability of the Concept of “Platinum Sensitivity” to Recurrent Endometrial Cancer

Abstract

The platinum-free interval is defined as the period between the completion of platinum-based primary chemotherapy for ovarian cancer and disease recurrence. Platinum sensitivity refers to women with ovarian cancer who have a platinum-free interval of more than 6 months. These women usually undergo platinum-based second-line chemotherapy; response rates range from 27% to 65% with a median survival of 12 to 24 months. Women with a platinum-free interval of less than 6 months are considered to be platinum resistant; response rates in these women to second-line chemotherapy is 10% to 30% with a median survival is 6 to 9 months. There are few data on the efficacy of second-line platinum-based chemotherapy for endometrial cancer. Also, there is no definitive evidence on the applicability of the concept of platinum sensitivity to recurrent endometrial cancer. This multicenter retrospective cohort study investigated the applicability of the concept of platinum sensitivity to recurrent endometrial cancer. The patient population was composed of 262 women with relapsed endometrial cancer who had a history of receiving first-line platinum-based chemotherapy. All had received second-line platinum-based chemotherapy at the time of recurrence between January 2005 and December 2009. The study examined the relationship between platinum-free interval and response to second-line platinum-based chemotherapy, as well as progression-free survival and overall survival after second-line chemotherapy. The initial International Federation of Gynecology and Obstetrics stage classifications for the 262 patients were as follows: I (n = 29), II (n = 23), III (n = 122), and IV (n = 88). Documented tumors included 153 endometrioid adenocarcinomas, 34 serous adenocarcinomas, 17 clear cell adenocarcinomas, 36 carcinosarcomas, and 22 other tumors. After second-line platinum-based chemotherapy, response rates for patients with platinum-free intervals of less than 6 months, 6 to 11 months, 12 to 23 months, and 24 months or more were 25%, 38%, 61%, and 65%, respectively. After second-line platinum-based chemotherapy, the median progression-free survival for patients with platinum-free intervals of less than 12 months and 12 months or more was 4.4 months (95% confidence interval [CI], 3.7–5.8) and 10.3 months (95% CI, 8.2–12.6), respectively (P < 0.0001, log-rank test), and the median overall survival was 13.8 months (95% CI, 10.6–18.1) and 40.9 months (95% CI, 25.3–54.2), respectively (log-rank P < 0.0001). These data show that the platinum-free interval is a predictor of response to second-line platinum-based chemotherapy and of survival in patients with recurrent endometrial cancer. The data indicate that the concept of platinum sensitivity can be applied to recurrent endometrial cancer.