The correlation of neutrophil/lymphocyte ratio and tumor reduction ratio in preoperative chermoradiotherapy for advanced rectal cancer.

633 Background: Preoperative chemoradiotherapy (CRT) is widely used for the treatment of advanced lower rectal cancer and is considered to reduce the local recurrence rate and improve the anus preservation rate. However, the tumor reduction effect varies among patients, and thus far, no factor has yet been found to be effective in the prediction of therapeutic efficacy. Recent studies have shown tumor immunity in the tumor microenvironment to be involved in the anti-tumor effect of radiation and anti-cancer drugs. Among these studies, some show that the neutrophil/lymphocyte (NL) ratio in blood test results correlates with the therapeutic efficacy. We examined the correlation between the NL ratio based on blood test results and tumor-reducing effect of preoperative CRT on advanced lower rectal cancers. Methods: We included 30 advanced lower rectal cancer patients who underwent preoperative CRT during the period ranging from January 2008 to June 2013.For advanced lower rectal cancers classified as cT3orT4N...