Prognostic significance of the immuno-peritoneal cancer index in peritoneal metastatic patients treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy

PurposeA valid comparison of immune function among different patients with different primary pathologies or even with different tumour burdens requires the common use of a reliable assessment of the patient's condition. The combined immuno-PCI system can translate a complex clinical situation into a simple point value to improve postoperative outcomes to assess the prognostic significance of combined immuno-PCI in peritoneal metastatic patients treated with cytoreductive surgery(CRS) and hyperthermic intraperitoneal chemotherapy(HIPEC).Patients and methodsFour hundred twenty-four patients from the prospectively maintained database of Dokuz Eylul University Peritoneal Surface Malignancy Center were retrospectively analysed. In addition to the demographic findings and the well-known clinicopathologic factors, several systemic inflammation-based prognostic scores, including the modified Glasgow prognostic score (mGPS), CRP-albumin ratio (CAR), neutrophil-lymphocyte ratio (NLR), neutrophil-thrombocyte ratio (NTR), and thrombocyte count, were all searched and stratified into scoring categories as prognostic determinants of surgical complications, final oncologic outcomes, recurrent disease, disease-free survival (DFS), and overall survival (OS). ROC analyses were performed, and cut-off values were obtained for all immune parameters by using the Youden index method.ResultsThere were 314 (74%) women and 110 (26%) men. The median age was 56 (ranging from 18 to 86) years. The most frequent sites of peritoneal metastasis were colorectal (n = 204; 48%) and gynaecologic carcinomas (n = 187; 44%). Thirty-three patients (8%) had primary malignant peritoneal mesothelioma. The median follow-up was 37.8 (ranging from 1 to 124) months. The overall survival was 51.7%. The 1-year, 3-year, and 5-year survival rates were estimated as 80%, 48.4%, and 32.6%, respectively. PCI-CAR-NTR (1 to 3) (p < .001) scoring was an independent prognostic factor for DFS. In a Cox backwards regression analysis, anastomotic leak (p = .002), completeness of cytoreduction (p = .0014), number of organ resections (p = .002), lymph node involvement (p = .003), and PCI-CAR-NTR (1 to 3) scoring (p = .001) were found to be independently significant prognostic factors for overall survival.ConclusionThe PCI is a reliable and consistently valid prognostic factor to evaluate the tumour burden and tumour extent in patients treated with CRS/HIPEC. Staging the host by combining the PCI with an immunoscore may help to improve the outcomes of complications and overall survival in these complex cancer patients. The aggregate maximum immuno-PCI tool may be a better prognostic measure for outcome evaluation.