The prognostic value of the systemic inflammatory score in patients with unresectable metastatic colorectal cancer.

Inflammation has been widely recognized as a contributor to cancer progression and several inflammatory markers have been reported as associated with the clinical outcomes in patients with various types of cancer. Recently, a novel inflammatory marker, the systemic inflammatory score (SIS), which is based on a combination of the lymphocyte-to-monocyte ratio (LMR) and the serum albumin concentration has been reported as a useful prognostic marker. The aim of the present study was to assess the prognostic value of the SIS in patients with unresectable metastatic colorectal cancer (mCRC). The retrospective cohort study included 160 patients who underwent combination chemotherapy for unresectable mCRC between January 2008 and December 2016. The SIS was used to classify the patients into three groups based on their LMR and the serum albumin concentration. Patients with high-LMR and high serum albumin level were given a score of 0; patients with low-LMR or low serum albumin level were given a score of 1; patients with low-LMR and low serum albumin level were given a score of 2. There were significant differences in the overall survival among the three SIS groups and the SIS was an independent prognostic factor for the overall survival. Although the SIS was significantly associated with the overall survival rate even when using the original cut-off values, the SIS according to the new cut-off values had a more accurate prognostic value. The present study determined that the SIS was a useful biomarker for predicting the survival outcomes in patients with unresectable mCRC, although the optimum cut-off value of the SIS according to the patients' background needs to be examined in further studies.