Carboplatin re-treatment in platinum-resistant epithelial ovarian cancer patients

Purpose: Treatment of multi-resistant epithelial ovarian cancer represents a clinical challenge with limited choices. Anti-angiogenic therapy has shown great potential in combination with frontline-therapy. Studies investigating heavily pre-treated patients are few. This study investigated the effect of re-treating patients with carboplatin combined with bevacizumab and cell-free DNA (cfDNA) as a potential predictor of outcome. Methods: This single-center study enrolled 73 multi-resistant ovarian cancer patients from 2008 to 2015. Patients were treated with a combination of bevacizumab (10 mg/kg) and carboplatin (AUC5) every 3 weeks. Baseline plasma samples were analyzed for cfDNA levels. Treatment response was evaluated based on the Response Evaluation Criteria in Solid Tumors (RECIST) criteria and CA125 blood values. Results: The response rate according to RECIST and/or CA125 was 57%. Median number of cycles was 6. The median progression-free survival and overall survival was 5.0 and 11.2 months, respectively. Eighteen patients developed allergic reactions to carboplatin. Patients were grouped into two cfDNA-groups according to median value. The cfDNA value was correlated to progression-free survival (PFS, p = 0.015), but not to overall survival (OS, p = 0.067) in the univariate analysis. In the multivariate analysis both PFS and OS were highly correlated to the levels of cfDNA (PFS, hazard ratio = 1.87, p = 0.012; OS, hazard ratio = 1.67, p = 0.037) with patients with high levels of cfDNA having poorest outcome. Conclusion: Our results might provide guidance in cases with heavily pre-treated patients, where alternatives are limited. Carboplatin and bevacizumab treatment should be weighed against best supportive care, current non-platinum therapies and experimental treatment. cfDNA seems to offer prognostic insight.