The impact of second to sixth line therapy on survival of relapsed ovarian cancer after primary taxane/platinum-based therapy

Despite recent progress in the treatment of ovarian cancer, the majority of patients eventually relapse. There is little information on the effectiveness of chemotherapy in higher treatment lines. Characterization of the second to sixth line therapy and its effects on survival was carried out, based on data of n = 1620 patients from three large randomized phase III trials investigating primary therapy. Median progression-free survival (PFS) after the first, second, third, fourth and fifth relapse was 10.2 [95% confidence interval (CI) 9.6-10.7], 6.4 (5.9-7.0), 5.6 (4.8-6.2), 4.4 (3.7-4.9) and 4.1 (3.0-5.1) months, respectively. Median overall survival (OS) after the first, second, third, fourth and fifth relapse was 17.6 (95% CI 16.4-18.6), 11.3 (10.4-12.9), 8.9 (7.8-9.9), 6.2 (5.1-7.7) and 5.0 (3.8-10.4) months, respectively. The most frequent second and third line chemotherapy was platinum combination (n = 313, 24.5%) and topotecan (n = 118, 23.6%), respectively. Relapse treatment improved PFS and OS at the second to fourth recurrence, although frequently not performed according to the standard of care. In multivariate analysis, platinum sensitivity and optimal primary tumor debulking were revealed as independent prognostic factors for PFS up to third relapse. A maximum of three lines of subsequent relapse treatment seems to be beneficial for patients with recurrent ovarian cancer. Optimal primary tumor debulking and platinum sensitivity remain independent prognostic factors even after more frequent relapses.