Abstract:

Objective To construct a progression-free survival prediction model based on the modeled carbohydrate antigen 125 （CA125） elimination rate constant K （KELIM） for patients with high-grade serous ovarian carcinoma （HGSOC） after neoadjuvant chemotherapy （NACT） and interval debulking surgery （IDS）. Methods The clinical data of 180 HGSOC patients who received NACT+IDS treatment at Linyi Cancer Hospital，Shandong Province from May 2022 to January 2024 were retrospectively collected. Patients were divided into a training set （126 cases） and a validation set （54 cases） in a 7∶3 ratio. The KELIM score during NACT was calculated. Kaplan-Meier method and log-rank test were used to compare the survival differences of patients with different KELIM scores，and multivariate Cox proportional hazard regression model was used to analyze the influencing factors of PFS. The prediction model of PFS after NACT+IDS treatment in HGSOC patients was constructed based on the KELIM score. The predictive efficacy of the PFS prediction model based on KELIM score were evaluated by receiver operator characteristic （ROC） curve and calibration curve. Results Among the HGSOC patients in the training set，59 cases had KELIM scores ≥1 point，and 67 cases had KELIM scores <1 point. Forty-five cases （35.71%） died due to disease progression or all-cause within one year after treatment. The restricted mean survival time （RMST） for PFS （11.3 months vs. 9.1 months） and for OS （11.7 months vs. 10.9 months） of the KELIM score ≥1 group were longer than those of the <1 group （χ²=14.07，P<0.001； χ²=4.74，P=0.030）. The proportion of patients aged ≥60 years with disease progression or all-cause mortality （χ²=6.37，P=0.012），patients in the International Federation of Gynecology and Obstetrics （FIGO） stage Ⅳ （χ²=7.62，P=0.006），postoperative non-R0 tumor residual （χ²=6.61，P=0.010），and KELIM score <1 （χ²=11.43，P<0.001） were higher than those who survived without progression. Multivariate analysis showed that age ≥60 years （HR=2.82，95%CI：1.50-5.29，P=0.001），FIGO stage Ⅳ （HR=2.23，95%CI：1.24-4.04，P=0.008），postoperative non-R0 tumor residual （HR=2.01，95%CI：1.10-3.65，P=0.022），KELIM score <1 （HR=3.30，95%CI：1.70-6.42，P<0.001） were all the independent risk factors of PFS after NACT+IDS treatment in HGSOC patients. Based on the above factors，a nomogram model was constructed，and the calibration curve showed that the predicted probabilities of the nomogram model in the training set and validation set were close to the actual probabilities，indicating good calibration. ROC curve analysis showed that the areas under the curve of the nomogram model for predicting PFS of the training and validation sets were 0.81 （95%CI：0.73-0.89） and 0.88 （95%CI：0.77-0.99），respectively. Conclusions The KELIM score is related to the PFS of HGSOC patients after NACT+IDS treatment. Patients with KELIM score <1 have shorter PFS and OS. The nomogram model constructed on the basis of the KELIM score demonstrates good performance in predicting PFS of HGSOC patients following NACT+IDS treatment.

Key words: Ovarian neoplasms, Cystadenoma, serous, CA-125 antigen, Kinetics, Cytoreduction surgical procedures, Progression-free survival