Neutrophil infiltration combined with necrosis in the primary tumor is a useful prognostic indicator for three-year disease-free survival time in patients with colorectal cancer

Histopathological evaluation plays a key role in the diagnosis of colorectal cancer (CRC). Tumor-related local inflammation is regarded as a novel prognostic parameter. Neutrophils constitute one of the main types of inflammatory cells. The aim of the present study was to evaluate the prognostic value of intratumoral tumor-associated neutrophils (intraTANs), stromal TANs (stromaTANs) and necrosis, as well as their combined parametric value in formalin-fixed paraffin-embedded tissue sections from patients with CRC. For this purpose, a retrospective study of 160 patients with CRC who underwent surgery was conducted. The association of intraTANs, stromaTANs, necrosis and their combined parametric value with the clinicopathological features of patients with CRC was examined. The Kaplan-Meier method and the log-rank test were used to compare survival curves. To identify independent prognostic factors, uni- and multivariate Cox proportional hazards regression models were used. StromaTANs were associated with lymph node metastasis (P=0.049) and tumor deposits (P=0.041). In addition, necrosis was found to be associated with venous (P=0.003), lymphatic (P=0.007) and perineural (P=0.015) invasion, as well as with lymph node metastasis (P=0.033), the number of invaded lymph nodes (P=0.012), and lymph node pouch invasion (P=0.043). Furthermore, necrosis was found to be associated with the white blood cell count (P=0.030), neutrophil count (P=0.011), the combined neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (NLR-PLR) (P=0.038), and the combined platelet and NLR (PLT-NLR status) (P=0.030), as well as with the serum carcinoembryonic antigen (CEA) levels following surgery (P=0.011) and the monocyte-to-lymphocyte ratio (P=0.023). The combined parametric value was found to be associated with pT stage (P=0.049), venous (P=0.034) and lymphatic (P=0.026) invasion, and with serum CEA levels prior to surgery (P=0.029). The analysis of the 3-year disease-free survival (DFS) time revealed that tumor growth [hazard ratio (HR), 2.070; 95% CI, 1.837-3.808; P=0.003] and the combined parametric value (intraTANs, stromaTANs and necrosis, HR, 1.577; 95% CI, 1.372-3.032; P=0.028) were independent factors for patients with CRC. Taken together, the findings of the present study demonstrated that the combined value of neutrophils and necrosis examined in the cancerous tissue may be used as a prognostic factor for the 3-year DFS time in patients with CRC.