Response rates to second-line platinum-based therapy in ovarian cancer patients challenge the clinical definition of platinum resistance
OBJECTIVE: The aim of this study was to compare response rates and survival in women with "platinum resistant" epithelial ovarian cancer (EOC) who received further platinum-based or nonplatinum chemotherapy for treatment at first relapse. METHODS: Patients with high-grade EOC (including fallopian tube and peritoneal cancer) of all histologies recruited to the Australian Ovarian Cancer Study (AOCS) and treated with platinum-based primary chemotherapy were included. Response to second-line chemotherapy, overall survival (OS) and survival after treatment for first progression (OS2) were determined in all histologies and separately in women with high-grade serous tumors. RESULTS: Of the 341 patients classified as platinum-resistant by the 6-month threshold, 243 (71%) were treated with chemotherapy at relapse. CA-125 response rates to platinum-based chemotherapy were significantly higher compared to nonplatinum chemotherapy (51% vs 21%, P<0.001). Among patients with a platinum-free interval (PFI) of 3-6months, OS2 in patients treated with platinum was significantly longer compared to individuals receiving nonplatinum-based treatment (median 17.67months, 95% CI: 14.79-20.75 vs. 10.62months, 95% CI: 8.02-12.72, P=0.022). The patterns were similar when restricted to patients with high-grade serous histology. In patients with PFI <3months, there was no significant difference in response or survival according to type of second-line treatment. CONCLUSIONS: Our findings further question the use of a 6-month PFI as an arbitrary threshold for subsequent treatment decision-making. Some patients considered "platinum resistant" still derive clinical benefit from platinum-based chemotherapy. Biomarkers of platinum sensitivity are needed in clinical practice to identify potential responders who should be offered re-treatment with platinum.
|Authors||Lindemann, K.; Gao, B.; Mapagu, C.; Fereday, S.; Emmanuel, C.; Alsop, K.; Traficante, N.; Harnett, P. R.; Bowtell, D. D. L.; deFazio, A.|
|Publisher Name||GYNECOLOGIC ONCOLOGY|