Long-term and short-term prognostic value of the prognostic nutritional index in cancer: a narrative review.

OBJECTIVE To perform a narrative review of the prognostic value of prognostic nutritional index (PNI) in cancers. BACKGROUND Prognostic estimation greatly determines the treatment approach in various cancers. The PNI, calculated using the serum albumin level and total lymphocyte count, is a useful indicator to assess nutritional and immunological conditions. The PNI represents a low-cost, easy-to-perform, noninvasive, rapid, and standardized tool for estimating the prognosis of cancer. Many studies have aimed to clarify the prognostic value of PNI for various types of cancer. METHODS We summarize the studies, particularly the systematic reviews and meta-analyses, that have examined the prognostic value of PNI in common cancers. CONCLUSIONS The relevant studies indicate that low PNI is an independent prognostic factor for decreasing overall survival in many types of cancers. Disease-free survival and progression-free survival were also associated with PNI in some types of cancer including lung cancer and renal cell carcinoma. Therefore, we suggest that the measurement of PNI is a useful method to identify cancer patients that have a worse prognosis and that the treatment strategy for these patients be adjusted accordingly. We hypothesize that maintaining good nutritional status during treatment may improve outcomes of various cancers.