Systemic inflammatory indices predict tumor response to neoadjuvant chemoradiotherapy for locally advanced rectal cancer.

Systemic inflammatory responses are associated with the prognosis of patients with colorectal cancer. However, the value in predicting tumor responses to neoadjuvant chemoradiotherapy (nCRT) remains to be elucidated. The current study aimed to investigate the association between systemic inflammatory indices and pathological complete response (pCR). The training and validation cohorts included 225 and 96 patients with locally advanced rectal cancer. The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio were recorded prior to nCRT and radical surgery. Univariate and multivariate analysis were used to investigate the association between systemic inflammatory indices and pCR. Systemic inflammatory indices prior to or following treatment had no significant association with pCR; however, the percentage change in NLR from pre-nCRT to post-nCRT was associated with a poor response, and a percentage change of >21.5% NLR (P=0.006; OR=0.413; 95% CI=0.22-0.773) was a predictor of poor pCR. Therefore, in rectal cancer, the percentage change in NLR from pre- to post-nCRT was found to be a predictor of poor pCR.