Prognostic value of a novel index combining the prognostic nutritional index and D-dimer levels for gastric cancer after gastrectomy

Introduction: The prognostic nutritional index and D-dimer level are two useful measures for gastric cancer prognosis. Since they each comprise different factors, it is possible to employ a more useful combined indicator. This study therefore aimed to establish a prognostic nutritional index-D score—which combines the prognostic nutritional index and D-dimer level—and validate its usefulness as a prognostic marker. Methods: We collected data from 1,218 patients with gastric cancer who had undergone radical gastrectomy (R0) between January 2004 and December 2015. Patients were divided into three prognostic nutritional index-D score groups based on the following criteria: score 2, low prognostic nutritional index (≤46) and high D-dimer levels (>1.0 µg/ml); score 1, either a low prognostic nutritional index or high D-dimer levels; and score 0, no abnormality. We then defined the PNI-D score as low (score 0 or 1) and high (score 2). Results: The prognostic nutritional index-D score was significantly associated with overall, recurrence-free, and disease-specific survival (all log-rank P<0.0001). The 5-year overall survival rates of the patients with prognostic nutritional index-D scores of low and high were 88.1% and 64.7%, respectively; their 5-year recurrence-free survival rates were 86.7% and 61.3%, respectively; and their 5-year disease-specific survival rates were 99.3% and 76.5%, respectively. Cox multivariate analysis revealed that a high prognostic nutritional index-D score was an independent, statistically significant prognostic factor for poor overall (P=0.01) survival in the patients with gastric cancer. Conclusions: The prognostic nutritional index-D is an independent prognostic factor for patients with gastric cancer.