Association Between Peritoneal Carcinomatosis Index (PCI) Assessed by CT and Pathological Parameters and Short-Term Prognosis of Rectal Cancer.

Objective: The study aimed at explore the correlation between the CT-based Peritoneal Carcinomatosis Index (PCI) and pathological parameters of rectal cancer, as well as the correlation with short-term postoperative prognosis.

Methods: A retrospective analysis was performed on 198 rectal cancer patients treated in our institution from January 2017 to December 2022. Based on preoperative CT-PCI, patients were classified into a normal and low CT-PCI groups. Baseline characteristics and short-term postoperative outcomes were compared between the two groups. Univariate and Multivariable logistic regression analyses were conducted to ascertain the independent risk factors for postoperative complications (Clavien-Dindo classification ≥ Grade II) following neoadjuvant treatment and radical rectal cancer surgery.

Results: There were significant statistical differences between the two groups regarding age, ASA score, and surgical method (P < .05). Variations in overall postoperative complications and complications of Grade II or higher among patients with differing preoperative CT-PCI were statistically significant (P < .05). No significant statistical difference was found in the time to first liquid intake post-surgery between the preoperative low CT-PCI group and the normal CT-PCI group (P > .05); however, differences in the time to first flatus, duration of postoperative hospital stay, and total hospital expenditure were statistically meaningful (P < .05). Multivariate logistic regression revealed that CT-PCI (OR=2.254) was an influential factor for postoperative complications (Clavien-Dindo classification ≥ Grade II) (P < .05). The ROC curve demonstrated an AUC of 0.854 for CT-PCI in predicting postoperative complications (Clavien-Dindo classification ≥ Grade II).

Conclusion: Preoperative CT-PCI may be utilized to evaluate the short-term prognosis of patients who undergo radical surgery for rectal cancer after neoadjuvant therapy. This evaluation assists in guiding clinical diagnostic and therapeutic decision-making, allowing for prompt interventions and enhancing short-term patient outcomes.