The prognostic impact of preoperative blood monocyte count in pathological T3N0M0 rectal cancer without neoadjuvant chemoradiotherapy

Abstract

It remains controversial whether adjuvant therapy should be delivered to pathological T3N0M0 rectal cancer without neoadjuvant chemoradiotherapy. Thus identification of patients at high risk is of particular importance. Herein, we aimed to evaluate whether the absolute peripheral blood monocyte count can stratify the pathological T3N0M0M0 rectal cancer patients in survival. A total of 270 pathological T3N0M0 rectal cancer patients with total mesorectal excision-principle radical resection were included. The optimal cut-off value of preoperative monocyte count was determined by receiver operating characteristic curve analysis. Overall survival and disease-free survival between low- and high-monocyte were estimated by Kaplan–Meier method and Cox regression model. The optimal cut-off value for monocyte count was 595 mm ³. In univariate analysis, patients with monocyte counts higher than 595/mm ³ had significantly inferior 5-year overall survival (79.2 vs 94.2 %, P = 0.006) and disease-free survival (67.8 vs 86.0 %, P < 0.001). With adjustment for the known covariates, monocyte count remained to be associated with poor overall survival (HR = 2.55, 95 % CI 1.27–5.10; P = 0.008) and disease-free survival (HR = 2.63, 95 % CI 1.48–4.69; P = 0.001). Additionally, the significant association of monocyte count with disease-free survival was hardly influenced in the subgroup analysis, whereas this correlation was restricted to the males and patients with normal carcinoembryonic antigen (CEA) level (<5 μg/L), tumor grade II, and with adjuvant therapy. High preoperative monocyte count is independently predictive of worse survival of pathological T3N0M0 rectal cancer patients without neoadjuvant chemoradiotherapy. Postoperative adjuvant therapy might be considered for patients with high-monocyte count.