Introduction/Background About 80% of patients with epithelial ovarian cancer (EOC) relapse in the first 2 years from diagnosis. Data on treatments after the second line are poor and based on small retrospective studies. Despite benefits after the third line are unclear, some patients are heavily treated with increased toxicities and hospitalization. Aim of the study is to investigate survival outcomes of EOC patients treated with ≥ three chemotherapy lines and to identify predictive factors of response to treatments, in order to adequately select patients who could benefit from subsequent chemotherapy lines.

Methodology Recurrent EOC patients received ≥ three lines of chemotherapy at Mauriziano Hospital of Turin between 2016 and 2022 were retrospectively analyzed. Progression-free survival (PFS) and overall survival (OS) were assessed according to chemotherapy lines. Prognostic factors associated with chemotherapy responses were investigated.

Results 68 patients and 180 lines of treatment were evaluated. OS progressively decreased with subsequent chemotherapy lines from 17 to 8 months, while PFS was not significantly reduced after third recurrence (p=0.558). Patients who received more lines of chemotherapy had better OS (p=0.018). In the multivariate analysis adjusted for clinicopathologic factors, platinum-sensitivity > 12 months and the administration of ≥ three lines of treatment were independent prognostic factors for OS (p<0.0001 and p=0.002, respectively), while ECOG and rechallenge with platinum for PFS (p=0.02 and p=0.0009, respectively). In the multivariate analysis according to single line of therapy, platinum-sensitivity (p=0.013), platinum rechallenge (p=0.016) and maintenance treatment (p=0.005) resulted associated with better PFS at the second recurrence and maintenance therapy preserved its prognostic value up to fourth line (p=0.015).

Conclusion Platinum-sensitivity and receiving ≥ three lines of treatment are independent prognostic factors for OS. Platinum-sensitivity, platinum rechallenge and maintenance therapy are associated with improved PFS in third line; maintenance therapy remains an independent prognostic factor even in subsequent treatments.

Disclosures The authors declare that there are no conflicts of interest.