Introduction/Background Complete cytoreduction (macroscopic Residual Tumor, RT = 0) is an independent prognostic factor in advanced epithelial ovarian cancer (AEOC). There are currently no validated criteria for predicting complete resection at interval debulking surgery (IDS). The aim of this study is to develop a non-invasive predictive model of complete cytoreduction to IDS.

Methodology From January 2013 to December 2022, 108 patients underwent neoadjuvant chemotherapy (NACT) and IDS at our institution and 79 patients met all the inclusion criteria. The correlation between clinico-pathological or haematological factors and complete resection was investigated by univariate and multivariate analysis. We developed a predictive model using all statistically significant variables.

Results At IDS, 53 patients (67.1%) had complete cytoreduction (RT=0). Four variables were statistically correlated with residual tumor: platelet-to-lymphocyte ratio (PLR), p = 0.002; neutrophil-to-lymphocyte ratio (NLR), p = 0.041; KELIM, p = 0.002; the CA125 value after the third chemotherapy cycle, p = 0.023. Considering all 4 parameters simultaneously, we developed a ROC curve with an AUC = 0.802, a sensitivity of 35%, specificity of 98% and positive predictive value (PPV) of 90%.

Conclusion Our model predicted residual tumor in a good number of patients undergoing IDS, limiting the percentage of patients with suboptimal cytoreduction. These parameters, calculated from blood samples, have low economic impact and no risk to the patient. The model should be prospectively validated in a larger series of EOC patients undergoing NACT-IDS.

Disclosures Nothing to disclose.