Objectives Response to platinum-based chemotherapy is considered to be one of the most important prognostic factors in recurrent ovarian cancer. Women with primary platinum resistance (PPR) have poor prognosis. Less is known regarding outcome in patients with secondary, acquired platinum resistance (SPR).

We evaluated response to treatment and survival in patients with PPR compared to patients with SPR.

Methods This retrospective cohort study included patients treated for ovarian, tubal and primary peritoneal cancer in Wolfson Medical Center during the years 2000–2015. The patients were categorized as PPR (disease recurrence less than 6 months after completing first line platinum based chemotherapy) and SPR (previously platinum sensitive disease that developed platinum resistance on subsequent treatments).

Results 118 patients were included in this study, 60 had PPR and 58 developed SPR. The SPR women had significantly higher rate of optimal debulking during their upfront and interval operations, significantly lower CA-125 levels during their primary treatment and significantly higher complete and partial response rate to primary chemotherapy. Nevertheless, once platinum resistance appeared, no significant difference in survival was observed between the two groups. The median PFS was 2 month in the PPR group and 0.83 month in the SPR group. Also, no significant difference was found in OS, median of 17.63 month in the PPR and 20.26 month in the SPR group.

Conclusions Platinum resistance is an important prognostic factor in women with ovarian cancer. Even with good response to primary surgery and chemotherapy, once platinum resistance appears the disease course is similar to patients with primary resistance.