Surgical complexity and scope of procedures necessary after neoadjuvant chemotherapy for primary ovarian cancer

Objective: The management of advanced ovarian cancer (AOC) has shifted, with neoadjuvant chemotherapy (NACT) followed by interval debulking surgery (IDS) surpassing primary debulking surgery (PDS) worldwide. This transition raises expectations for reduced need for high-complexity surgery at IDS. Our goal was to objectively evaluate surgical complexity required at IDS. Methods: This retrospective cohort study included patients with stage IIIC-IVB AOC undergoing IDS or PDS between 2016 and 2021 at Mayo Clinic, Rochester, and the European Institute of Oncology, Milan. Surgical procedures were classified by anatomical location and deemed advanced if not routinely performed by gynecologic oncologists during standard staging procedures. Chi-squared tests were used to compare rates of advanced procedures between IDS and PDS. Results: Of 1170 patients, 612 underwent NACT-IDS and 558 PDS. Advanced surgical procedures were performed in 51.5 % of IDS and 83 % of PDS cases. Upper abdominal procedures were necessary in 41.2 % of IDS and 71.1 % of PDS cases. Surgical complexity score was intermediate-to-high in 56.7 % of IDS and 88.45 % in PDS cases. CA-125 normalization post-NACT was not a specific predictor of low complexity surgery. Complete gross resection (CGR) was achieved in 61.6 % and 70.3 % of IDS and PDS cases, respectively. Conclusions: Over half of IDS cases after NACT require advanced surgical procedures, including upper abdominal surgery. Given the prognostic significance of achieving CGR at IDS, efforts to maintain and expand specialized expertise is necessary, including advanced surgical training for gynecologic oncologists. Reliable predictors of complexity are urged for tailored surgical planning.