Systemic inflammatory response after preoperative chemoradiotherapy can affect oncologic outcomes in locally advanced rectal cancer

Aim: Systemic inflammatory response (SIR) has been reported to be an important determinant of disease progression and survival in patients with colorectal cancer. This study investigated the prognostic relevance of changes in the platelet count on survival and the predictive value of changes in platelet/lymphocyte ratio (PLR) and neutrophil/lymphocyte ratio (NLR) on the pathological tumor response to preoperative chemoradiotherapy (CRT) in patients with locally advanced rectal cancer (LARC). Patients and Methods: From 2006 to 2015, 291 consecutive patients with LARC who were treated with preoperative CRT followed by curative surgery at the Kyungpook National University Medical Center (Daegu, Korea) were retrospectively analyzed. A cut-off value of 370×103/l for the platelet count was used and a PLR 235 was defined as high. Any change in the PLR or NLR was calculated based on subtracting the pre-CRT PLR or NLR from the post-CRT values. Results: A total of 17.5% patients had stage II and 82.5% had stage III LARC. Initially high NLR and PLR were significantly associated with poor clinical outcomes. Patients who maintained a high platelet count after CRT also had an advanced pathological stage (p=0.028), low pathological complete response rate (p=0.048), and high relapse rate (p=0.021). For patients with an initially low PLR, the multiple logistic regression analysis revealed that a high PLR change (odds ratio (OR)=2.301, 95% confidence interval (CI)=1.269-4.174; p=0.006) and clinical stage II compared to stage III (OR=1.878, 95% CI=1.231-2.865; p=0.003) were significant independent markers predictive of a good response to CRT. Conclusion: The present results suggest that platelet and PLR change after preoperative CRT, along with the initial platelet count, can be used as prognostic and predictive markers for the oncological outcomes in patients with LARC.