Change in the neutrophil-to-lymphocyte ratio during chemotherapy may predict prognosis in patients with advanced or metastatic colorectal cancer

The neutrophil-to-lymphocyte ratio (NLR) has been reported to be an independent prognostic factor of unresectable advanced or metastatic colorectal cancer (uCRC). However, few studies have documented changes in NLR during chemotherapy. The current study analyzed whether a change in NLR during chemotherapy in patients with uCRC could be used as a prognostic biomarker. The present retrospective study enrolled 71 patients who received first-line chemotherapy for uCRC between April 2012 and April 2019. The exclusion criteria were as follows: Acute infection or systemic inflammatory disease, duration of first-line chemotherapy <3 months, curative resection after chemotherapy and treatment with granulocyte-colony stimulating factor within 1 month. NLR, Lymphocyte-to-monocyte ratio (LMR), platelet-to-lymphocyte ratio (PLR), lactate dehydrogenase, alkaline phosphatase (ALP), albumin, carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) levels were calculated before chemotherapy and at 3 months after chemotherapy. Among these laboratory data, NLR, PLR, ALP, CEA and CA19-9 levels were significantly decreased during chemotherapy. For Cox univariate analyses, these five data makers were divided into two groups: Decreased and increased (comparing before and at 3 months after chemotherapy). Only the change in NLR was significantly associated with overall survival (P=0.0002). Furthermore, the overall survival (P<0.0001) and progression-free survival (P=0.0041) of patients with decreased NLR was increased compared with patients with increased NLR. The change in NLR from pre-chemotherapy to 3 months following chemotherapy was determined to be a predictor of prognosis in patients with uCRC. The ability to predict prognosis at an early phase of chemotherapy may provide useful information for the selection of subsequent treatment and may improve the quality of patient life.