Background:The systemic inflammation-based prognostic scores, modified Glasgow Prognostic Score (mGPS) and the neutrophil-lymphocyte ratio (NLR) are now recognised to be useful in predicting survival in a variety of solid organ malignancies, including colorectal cancer (CRC) before treatment. However, there would appear to have been no direct comparison of these longitudinal measurements of systemic inflammation. Therefore, the aim of the present study was to compare the prognostic value of longitudinal measures of systemic inflammation, the mGPS and NLR in patients undergoing potentially curative resection for CRC.Methods:Three hundred and twenty-six patients underwent potentially curative resection for CRC between 2006 and 2010. Full biochemical and haematological data both pre- and post-operatively (3–6 months) were available for 206 patients.Results:In 206 patients, there was no significant overall change in either the mGPS or the NLR, from pre- to post-operatively. On univariate survival analysis, T-stage (P<0.001), tumour, node, metastasis stage (P<0.005), pre-operative mGPS (P<0.05), pre-operative NLR (<0.05), post-operative mGPS (P<0.001) and post-operative NLR (P<0.005) were associated with cancer-specific survival. On multivariate survival analysis, comparing pre-operative mGPS and NLR, both pre-operative mGPS and NLR were independently associated with reduced cancer-specific survival (mGPS hazard ratio (HR) 1.97, CI 1.16–3.34, P<0.05, and NLR HR 3.07, CI 1.23–7.63, P<0.05). When the same multivariate comparison was carried out on post-operative data, only the post-operative mGPS was independently associated with cancer-specific survival (HR 4.81, CI 2.13–10.83, P<0.001).Conclusion:The results of the present study support the longitudinal assessment of the systemic inflammatory response, in particular the mGPS, in patients undergoing potentially curative resection for CRC.