Publication

BACKGROUND: The prognostic nutritional index (PNI), which is calculated using serum albumin and the peripheral lymphocyte count, is a simple and useful score for predicting the prognosis in patients with various cancers. The correlation between the preoperative PNI and long-term outcomes is unclear in oldest-old patients with colorectal cancer. METHODS: A total of 84 consecutive patients ≥ 85 years old who underwent resection for primary colon adenocarcinoma at our institution between April 2008 and March 2017 were retrospectively reviewed. The cut-off value of the PNI for predicting the relapse-free survival (RFS) was 42.4 on a receiver operating characteristic curve analysis. The clinical characteristics and markers of systemic inflammation were then compared between patients with a low PNI (PNI < 42.4, n = 33) and a high PNI (PNI ≥ 42.4, n = 51). RESULTS: A low PNI was associated with systemic inflammation marker levels, including a low neutrophil-to-lymphocyte ratio (p = 0.048), a low platelet-to-lymphocyte ratio (p = 0.006), and a high lymphocyte-to-monocyte ratio (p < 0.001). The median follow-up period of this cohort was 34 months (1-151 months). The 5-year RFS, overall survival (OS), and cancer-specific survival were significantly worse in the low-PNI group than in the high-PNI group (p = 0.032, p = 0.004, p = 0.049, respectively). In the multivariate analysis, a low PNI was an independent predictor for both the RFS (HR 3.188, p = 0.041) and OS (HR 3.953, p = 0.027). CONCLUSIONS: A low-preoperative PNI was significantly associated with a poor prognosis in oldest-old colorectal cancer patients. Perioperative nutritional support may be important for prolonging the survival.