ObjectiveTreatment selection for recurrent ovarian cancer is typically based on the duration of time between the completion of adjuvant, platinum-based therapy and the time of recurrence, the platinum free interval (PFI). We examined the use of, and outcomes associated with platinum-based chemotherapy based on the PFI in women with recurrent ovarian cancer. MethodsThe Surveillance, Epidemiology, and End Results-Medicare database was used to identify women aged >65years with epithelial ovarian cancer who underwent surgery and platinum-based chemotherapy and who developed a recurrence >3months after the completion of adjuvant therapy. Patients were stratified by PFI into 3 groups: PFI <6months, PFI 7–12months, and PFI >12months. Multivariable models were used to examine predictors of use of platinum-based therapy and survival for each group. ResultsA total of 2369 patients were identified. In women with a PFI of ≤6months, treatment consisted of platinum-based combination therapy in 28.2%, single agent platinum in 5.2% and non-platinum therapy in 66.6%. Corresponding rates of these treatments among women with a PFI of 7–12months were 39.7%, 12.4% and 47.9%, respectively; the rates were 57.6%, 13.2% and 29.3% in those with a PFI of >12months, respectively. Median survival was 13, 18, and 27months for patients with a PFI of ≤6months, 7–12months, and >12months, respectively (P<0.0001). For all three groups, platinum combination therapy was associated with decreased risk of death compared to non‑platinum based therapy. ConclusionPlatinum free interval is a strong predictor of survival in elderly women with recurrent ovarian cancer. There is widespread variation in treatment selection for women with recurrent ovarian cancer with many women receiving non-guideline based regimens.