Exploring the association between homologous recombination status, KELIM, and resectability in high-grade serous ovarian cancer.

OBJECTIVE

We aimed to evaluate the association between KELIM and achievement of complete cytoreduction (R0; no macroscopic residual disease) in patients with high-grade serous ovarian carcinoma and to determine whether its performance and candidate thresholds vary according to homologous recombination status.

METHODS

This single-center retrospective study included patients with high-grade serous ovarian carcinoma treated with neoadjuvant chemotherapy between January 2010 and December 2025. KELIM was calculated for each patient and categorized as favorable (≥1) or unfavorable (<1). Associations with residual disease (R0, no macroscopic residual disease; R1, residual tumor <1 cm; or R2, residual tumor ≥1 cm) were assessed. Receiver operating characteristic curves identified candidate KELIM cutoffs. We evaluated the association of KELIM and homologous recombination status with progression-free survival; survival outcomes were analyzed using Kaplan-Meier estimates and Cox proportional hazards models. Sub-group analyses were performed according to homologous recombination status.

RESULTS

Overall, 145 patients were included. Median age was 64 years (interquartile range 57 to 73), and median KELIM was 0.93 (interquartile range 0.91 to 1.02). Patients with favorable KELIM (n = 58) had significantly higher R0 rates than those with unfavorable KELIM (n = 87) (77.6% versus 47.1%, p =.0002). Receiver operating characteristic analysis demonstrated moderate predictive performance for R0 (area under the curve 0.668; candidate cutoff 0.995). Candidate KELIM thresholds were lower in homologous recombination-deficient tumors (0.74) and breast cancer gene mutated tumors (0.745) than in homologous recombination-proficient tumors (0.94). Favorable KELIM was not significantly associated with progression-free survival (hazard ratio 0.78, 95% confidence interval 0.54 to 1.13, p =. 20). Median progression-free survival was numerically longer among patients with favorable KELIM compared with unfavorable KELIM (16.6 vs 13.7 months), although this difference was not statistically significant.

CONCLUSIONS

KELIM was associated with complete cytoreduction in patients with high-grade serous ovarian carcinoma, with differences observed according to homologous recombination status. These findings highlight the need for further investigation of candidate KELIM thresholds across distinct molecular sub-types to determine whether subtype-specific approaches may improve its clinical applicability.