EXTENding the timing for Secondary cytoreductive surgery after second line chemotherapy In relapsed OvariaN cancer: the EXTENSION study.

Relapse remains a major issue for patients with advanced epithelial ovarian cancer. Based on the DESKTOP III trial, international guidelines recommend secondary cytoreduction surgery when feasible before starting chemotherapy in platinum-sensitive relapsed ovarian cancer. Currently, neoadjuvant chemotherapy before secondary cytoreduction surgery is not advised outside of clinical trials. Recently, CHIPOR trial has shown the efficacy of secondary cytoreduction surgery with hyperthermic intra-peritoneal chemotherapy after neoadjuvant chemotherapy in an unselected population with platinum-sensitive relapsed ovarian cancer. The primary aim of this study was to assess the rate of potential delayed secondary cytoreduction surgery after 6 cycles of neoadjuvant chemotherapy. This retrospective, monocentric, observational study included patients with platinum-sensitive relapsed ovarian cancer deemed unsuitable for secondary cytoreductive surgery after evaluation by a multidisciplinary tumor board and/or diagnostic laparoscopy from January 2020 to December 2023. After 6 cycles of neoadjuvant chemotherapy, secondary cytoreduction surgery feasibility was evaluated by applying criteria for upfront secondary cytoreduction surgery in patients with at least a partial response at computed tomography scan. Overall, 522 patients with platinum-sensitive relapsed ovarian cancer were evaluated; 165 were considered unsuitable for upfront secondary cytoreduction surgery and received second-line chemotherapy. After 6 cycles of neoadjuvant chemotherapy, secondary cytoreduction surgery was considered feasible in 48 patients (29.1%, group A), while 117 patients (70.9%, group B) remained ineligible for surgery. Predictors of secondary cytoreduction surgery feasibility were analyzed. Multivariate analysis identified a favorable modeled CA125 elimination rate constant K score at second-line chemotherapy (OR 7.29, 95% CI 2.91 to 18.30, p < .001) as the only independent predictor. Patients eligible for delayed secondary cytoreduction surgery showed significantly longer progression-free survival 2 and post-relapse survival (median progression-free survival 2 12.5 vs 7.9, p < .001; median post-relapse survival: not reached vs 28.5, p = .002). In a real-life approach in a tertiary oncological center, we showed that around 30% of women with platinum-sensitive relapsed ovarian cancer, initially deemed unsuitable for secondary cytoreduction surgery, can potentially undergo delayed secondary cytoreduction surgery following a favorable response to 6 cycles of neoadjuvant chemotherapy.