Introduction/Background Neoadjuvant chemotherapy (NACT) followed by interval debulking surgery (IDS) is treatment option for patients with advanced epithelial ovarian cancer (EOC). The modulated CA-125 elimination rate constant K (KELIM) is marker of chemosensitivity, and no residual macroscopic disease after surgery is the most important predictive factor. Our aim was to investigate the relationship between KELIM score and cytoreduction outcome in EOC patients undergoing NACT.

Methodology Retrospectively, we have analysed the medical data of patients with EOC stage IIIB-IVB treated with NACT at the Department of Gynaecologic Oncology, the University Hospital Zagreb from January 2020 to June 2022. The KELIM score was calculated based on at least 3 CA-125 values. The patients are divided into two categories according to KELIM score: group 1 (KELIM score <1) and group 2 (KELIM score ≥1).

Results Our analysis included 65 patients: 30 (46%) patients in group 1 compared with 35 (54%) in group 2. The median age was 65 years in both groups. ECOG performance status 0–1 had 56.7% of patients in group 1 and 60% in group 2. The most commonly used chemotherapy protocol in both groups was paclitaxel/carboplatin. Three or four cycles of NACT was used in 40% of patients in group 1, compared 46% in group 2, and the others received more than 4 cycles NACT. Bevacizumab was administered to 13 (43%) patients in group 1 and to 16 (46%) in group 2. Thirty-three (94%) of patients underwent surgery in the group with a KELIM score ≥1, compared with only 19 (63%) in group 1. Among patients with a KELIM score <1, only 23% underwent complete surgical procedure without residual disease, compared with 80% in group 2.

Conclusion Patients with advanced EOC undergoing NACT with KELIM <1 were more likely to have platinum-resistant disease and they are less likely to achieve surgery without residual disease.

Disclosures The authors have declared no conflicts of interest.