Impact of the preoperative prognostic nutritional index on postoperative and survival outcomes in colorectal cancer patients who underwent primary tumor resection: a systematic review and meta-analysis.

PURPOSE: We aimed to explore whether the preoperative prognostic nutritional index (PNI) could be an indicator of prognostic outcomes in colorectal cancer (CRC) patients.

METHODS: A systematic review and meta-analysis was conducted using the PubMed, Embase, and Web of Science databases. All original comparative studies published in English that were related to a high PNI versus a low PNI in CRC patients were included.

RESULTS: A total of 10 studies involving 6372 patients were included in our meta-analysis. Our overall analysis indicated that the low-PNI group had a significantly reduced overall survival (OS) (HR = 1.87, 95% CI = 1.45-2.42, P < 0.01), cancer-specific survival (HR = 1.53, 95% CI = 1.07-2.19, P = 0.02), and disease-free survival (HR = 1.67, 95% CI = 1.23-2.26, P < 0.01) compared with the high-PNI group. Furthermore, our subgroup results indicated that a high PNI could be a significant indicator of improved OS in TNM stage II (HR = 1.93, 95% CI = 1.29-2.90, P < 0.01) and III (HR = 1.71, 95% CI = 1.25-2.34, P < 0.01), and a similar trend in TNM stage I or IV could also be observed though without statistical significance. Regarding postoperative complications, our pooled results indicated that the low-PNI group had a significantly increased incidence of total and severe postoperative complications.

CONCLUSIONS: Our findings indicated that CRC patients with a preoperative high PNI had a significantly improved OS. However, almost only Asian CRC patients were included based on current issue.