Background: Onodera's prognostic nutritional index (OPNI), which is calculated using total lymphocyte count and serum albumin level, has been used as a marker of nutritional status, with its potential prognostic value in colorectal cancer having recently been postulated in Japan and China. There is still no data on the predictive value of OPNI in a Western population.
Patients and methods: A consecutive case series of 207 patients scheduled for colorectal cancer resection with curative intent was reviewed. Pre-treatment OPNI was calculated using the formula: [10 x serum albumin (g/dl) + 0.005 x lymphocytes/mm²]. OPNI values under 40 were considered low. Univariate and multivariate analysis were performed on survival curves, comparing cases with OPNI values less than, equal to or greater than 40 (Cox model, stepwise), in the overall series and in pTNM stage II.
Results: The median for clinical follow-up was 81 months (interquartile range 60-96). Twenty-six patients (12.6%) had a low OPNI (≤ 40). In the multivariate analysis, patients with low OPNI showed less favourable survival curves, both in the overall series: [p <0.001; HR = 3.16; 95% CI = 1.67-5.94] and in the 78 cases in pTNM stage II: [p <0.004; HR = 4.36; 95% CI = 1.61-11.76].
Conclusions: A low pre-treatment OPNI (<40) has an independent, unfavourable predictive value on survival in European patients with resected colorectal cancer, both in the overall series and in pTNM stage II.