Effect of neoadjuvant chemotherapy on primary and metastatic tumour burden in epithelial ovarian cancer: a retrospective analysis of oncologic surgeries at a university hospital

Objective.To assess the effect of neoadjuvant chemotherapy (NACT) on pathological tumour burden in the primary tumour site and metastatic regions in patients with advanced epithelial ovarian cancer (EOC). Materials and Methods.This retrospective study included FIGO stage III-IV EOC patients who underwent either primary debulking surgery (PDS) or NACT followed by interval debulking surgery (IDS).Tumor involvement in the ovaries (primary site) and other anatomical locations (metastatic sites) was recorded separately.Pre-treatment CA-125 levels and postoperative pathological findings were compared between groups.Results.Seventy-six patients were evaluated (36 NACT+IDS, 40 PDS).Pre-treatment CA-125 levels were significantly higher in the NACT group.Although direct quantitative measurement of tumour burden was not performed, NACT-treated patients showed a marked decrease in CA-125 levels and a clinically evident reduction in tumour volume at IDS. Pathological assessment revealed lower tumour involvement in the ovaries after NACT, whereas metastatic site involvement remained comparable between the groups. Conclusions.NACT may reduce primary tumour burden and facilitate cytoreductive surgery; however, its effect on metastatic regions appears limited.These findings support the possibility that biological heterogeneity may contribute to regional differences in chemotherapy response.Given the retrospective design, limited sample M a n u s c r i p t a c c e p t e d f o r p u b l i c a t i o n size, and absence of standardized histopathologic response scoring or molecular profiling, prospective multicentre studies incorporating detailed molecular characterization are required to better elucidate NACT response patterns in EOC.