Platinum-free interval affects efficacy of following treatment for platinum-refractory or -resistant ovarian cancer.

Background/

Objective: Platinum-refractory or -resistant ovarian cancer (PRROC) is associated with poor prognosis and low response to further chemotherapy. We investigated predictors of effectiveness of following treatments for PRROC. Patients and

Methods: We included 380 patients diagnosed with stage I-IV ovarian, fallopian tube, or primary peritoneal cancer, who were treated at the National Cancer Center Hospital in Japan from January 2007 to December 2014 and recurred after initial treatment, who had a platinum-refractory or -resistant relapses and received chemotherapy, in this single-center, retrospective study. We investigated factors related to response to following treatment, and to progression-free survival (PFS).

Results: Among 183 patients (48%) who suffered recurrences, 62 (34%) developed PRROC after chemotherapy. In multivariate analysis, platinum-free interval (PFI) < 3 months was independently associated with progressive disease (odds ratio [OR] 6.043, 95% confidence interval [CI] 1.485-24.595, P = 0.012). Median PFS was 139 days (95% CI 19.4-258) among patients with PFI > 3 months, but was 57 days (95% CI 34.7-79.2) among those with PFI < 3 months. In multivariate analysis, two factors, performance status (PS) 1-2 (HR 1.915, 95% CI 1.074-3.415, P = 0.028) and PFI < 3 months (HR 1.943, 95% CI 1.109-3.403, P = 0.02), were independently associated with worse PFS.

Conclusions: PS 1-2 and PFI < 3 months were significant predictors of poor response to following treatment for PRROC. Risks and benefits of treatment should be frankly discussed with patients who have these characteristics.