Peritoneal cancer index in ovarian cancer: what does the surgeon really see?

Introduction: The aim of this paper is to study the agreement between the findings described by the surgeon during surgery (surgical Peritoneal Cancer Index or sPCI) and those obtained after the histopathological analysis (pathological Peritoneal Cancer Index or pPCI) of the resection specimens, in addition to their prognostic implications.

Materials and methods: A consecutive series of patients diagnosed with high-grade serous ovarian cancer with peritoneal dissemination was analyzed between January 2008 and December 2022. sPCI were correlated with the pPCI results. The study considered the surgeon as a diagnostic tool and established, in ovarian cancer, the parameters of sensitivity, specificity, predictive values, and probability coefficients. Specifically, the study focused on the subgroup of patients with false-positive results from sPCI compared to pPCI and its usefulness in assessing the prognosis of the disease.

Results: A total of 231 patients were included, evaluating a total of 3003 peritoneal areas. The median sPCI was 9 (range: 0-35) and 7 for pPCI. Of the 3,003 peritoneal areas evaluated, 132 areas were considered false positives for sPCI. After multivariate analysis, the location of the lesions in the supramesocolic compartment (OR 2.37, 95% CI 1.19-4.53, p = 0.014) was the only independent factor related to a false-positive sPCI result. Patients with false-positive sPCI had a better disease-free survival estimate.

Conclusions: The main usefulness of pPCI would be determined by its ability to correct prognostic estimates of the disease, especially in the case of false positives.