Chemotherapy is of Value in Second Line and Beyond, Relapsed High-grade, Serous Epithelial Ovarian Cancer

Abstract

Epithelial ovarian cancer is chemotherapy responsive, and multiple lines of chemotherapy are often given. However, there are few data with regard to its effectiveness in later lines. Our aim was to assess its benefit in the high-grade, serous subtype relative to the line of therapy, using etoposide as the example. Women treated with oral etoposide at the British Columbia Cancer Agency upon recurrence/progression in the years 2000 to 2010 were reviewed. Kaplan-Meier and Cox regression methods were used to correlate line of therapy with overall survival, progression-free survival, and interval between etoposide initiation and next progression or death (EPFS). A total of 219 women, median age 61, received etoposide as second (17%), third (30%), fourth (26%), fifth (17%), and sixth to eighth (11%) lines of therapy. The median number of cycles was 2 to 4. Patients who received etoposide as fourth-line to eighth-line treatment had a significantly longer median overall survival and initial progression-free survival (from diagnosis to first relapse) when compared with those who received it as second-line to third-line treatment (47.8 vs. 25.8 mo, P<0.0001; and 16.1 vs. 12.1 mo, P<0.0001, respectively); that is, a selected population of survivors received it later in the course of their disease. On univariate analysis, there was no significant difference in median EPFS (range, 2 to 2.9 mo) on the basis of line of therapy. On multivariate analysis, the hazard ratios improved through the third, fourth, and fifth lines (hazard ratios: 0.82, 0.77, and 0.34, respectively), and was statistically significant in the fifth line. The a priori-defined endpoint of clinical benefit was the "percentage not progressing at 3 months," and this was achieved in 32% to 48%. In this retrospective study, a similar degree of benefit from etoposide, as defined by the percentage remaining progression free at 3 months, was seen in all lines of therapy.