Association of Chemotherapy Response Score with Multidrug Resistance 1 and CA125 ELIMination Rate Constant K in Patients with Advanced Ovarian Cancer Treated with Neoadjuvant Chemotherapy.

The relationship between chemotherapy response score (CRS), a widely used response predictor of neoadjuvant chemotherapy-interval debulking surgery (NAC-IDS), and multidrug resistance 1 (MDR1) and CA125 ELIMination rate constant K (KELIM), is undetermined. We evaluated CRS in advanced ovarian cancer patients undergoing NAC and looked for associations between CRS and MDR1 and CA125 KELIM. Our aim was to predict the therapeutic effect of NAC before interval debulking surgery (IDS) by examining its association with CRS. This retrospective cohort study included patients who underwent NAC-IDS (first-line treatment) at Kurume University Hospital, Japan, between 2004 and 2017. CRS association with MDR1 and CA125 KELIM was examined using Cox proportional hazard regression analyses. Survival curves used Kaplan-Meier method, and survival differences between groups used log-rank test. Overall, 55 patients were classified into CRS1 (n=22), CRS2 (n=19), and CRS3 (n=14). The CRS3 group had a significantly better prognosis than the CRS1 or CRS2 group. CRS, age, and IDS status were clinical prognostic factors for ovarian cancer. MDR1 positivity for excision repair cross-complementing group 1, β-tubulin, and Y-box binding protein-1 occurred in 15, 17, and 11 patients, respectively, but these were not associated with CRS. CA125 KELIM was <0.5 (n=8), 0.5-1.0 (n=30), and ≥ 1.0 (n=17) but not associated with CRS. CRS is reconfirmed as a treatment response predictor for NAC-IDS, but its association with drug resistance factors remains unconfirmed.