Secondary Cytoreduction for Ovarian Cancer Relapse: Results From the High Surgical Quality, Multicenter “Surgery in Recurrent Ovarian Cancer Research Consortium” (Surroc-Con)

Objective To evaluate the effect of secondary cytoreductive surgery on survival outcomes in patients with ovarian cancer recurring more than 6 months after first-line therapy, treated at specialized high-volume centers. Methods Exploratory data analysis of prospective registries of 5 cancer centres in Europe & USA (2004-2022). Patients with first recurrence of any epithelial ovarian cancer >6 months following 1 st -line chemotherapy were eligible. To minimize selection bias, all eligible patients who received any anticancer treatment were evaluated. Overall and progression-free survival were calculated from the date of recurrence. All statistical tests were two-sided. Results Of 3,109 included patients, 38.7% underwent secondary cytoreduction; 83.6% with complete clearance. Mean and median platinum-free intervals were 33 and 23 months (range; 6-300). All three scores (AGO, iMODEL and MSK-criteria) had similar predictive values for complete clearance. Median overall survival was 81 months (95%CI 73-88) after complete clearance versus 39 months (95%CI 33-44) (p<0.001) with residual disease. Median overall survival with chemotherapy alone was 34 months (95%CI:33-36). BRCA1 /2 mutations significantly improved progression-free survival after secondary cytoreduction (27.4 vs. 21.3 months, p<0.0021) but not overall survival and did not retain its effect in the complete gross resection-cohort. Timing of initial cytoreduction did not significantly affect secondary cytoreduction benefit. Median overall survival without previous maintenance therapy was 73 (95%CI 65-79) versus 55 (95%CI 47-63) after previous bevacizumab versus 44 (95%CI 32-56) months after previous PARPi (p=0.0056). Unifocal relapse, platinum-free interval>16mo, age<75 years, CA125<105 U/ml, ECOG0, initial FIGO-stage I/II, <500ml ascites, non-mucinous histologies and complete gross resection were associated with significantly improved overall survival post-secondary cytoreduction. Conclusions Secondary cytoreductive surgery performed at specialized high-volume centers was associated with substantially prolonged overall survival compared with chemotherapy alone, particularly when complete gross resection was achieved. Neither BRCA status nor timing of initial cytoreduction significantly influenced this benefit, whereas prior maintenance therapy with PARP inhibitors and/or bevacizumab was associated with shorter overall survival after surgery.