Prognostic Nutritional Index as a Predictor of Postoperative Outcome in Patients Aged 85 Years or Older After Colorectal Cancer Surgery

The preoperative prognostic nutritional index (PNI) calculated based on the serum albumin concentration and peripheral blood lymphocyte count has been reported to correlate with the prognosis in patients undergoing cancer surgery. However, in case of very old patients over 85 years old, the value of preoperative PNI in colorectal cancer has not been studied in any detail. The aim of this study was to assess the PNI as a predictor of postoperative outcome in elderly patients over 85 years old with colorectal cancer. We performed a retrospective review in forty-five patients over 85 years old who underwent colorectal tumor resection at our hospital from April 2013 to March 2018. The correlations between preoperative PNI and postoperative complications were examined. The incidence rate of postoperative complications was 31.1% (14/45). All of cases with postoperative complications were improved conservatively. The median preoperative PNI was 43.20 (range 24.05–57.05) in the validation study. According to the receiver operating characteristic (ROC) curve, cutoff value of PNI was set at 45.0 in the validation study. An univariate analysis demonstrated that PNI (p = 0.0006), operation style (elective/emergency) (p = 0.03), operation approach (open/laparoscopy) (p = 0.03), and T factor (p = 0.04). A multivariate analysis showed that PNI was independent predictive factor of postoperative complications. Moreover 3-year overall survival rates of patients in the PNI ≧ 45 and PNI < 45 were 100% and 63.8%, respectively (p = 0.009). This study suggested that PNI is a pivotal independent predictor of the postoperative outcome among elderly patients over 85 years old after colorectal cancer surgery.