Chemotherapy-induced neutropenia and the prognosis of colorectal cancer: a meta-analysis of cohort studies

Introduction: Recently, there has been a controversial discussion about the prognostic value of chemotherapy-induced neutropenia (CIN) in colorectal cancer patients. Thus, a meta-analysis was conducted to determine the relationship between CIN and the prognosis of colorectal cancer patients.Methods: We searched the PubMed, EMBASE, and Cochrane library databases to identify studies evaluating the association between CIN and colorectal cancer prognosis. Pooled random/fixed effect models were used to calculate pooled hazard ratios (HRs) and 95% confidence intervals (CIs) to assess the association.Results: Eight studies were selected for the meta-analysis, for a total of 2,745 patients. There was significant improved survival among colorectal cancer patients with CIN (HR=0.62, 95% CI=0.47-0.76). However, significant heterogeneity was found (p=0.000, (2)=75.0%). Through subgroup analysis, we could greatly eliminate the heterogeneity and found that neutropenia was associated with better survival in stage IV colorectal cancer patients, no matter the HR calculated by overall survival (OS) or progression-free survival (PFS). Meanwhile, the prognostic value of neutropenia in stage II/III colorectal cancer can be found when the HR is calculated by disease-free survival (DFS). Additionally, we observed significant differences after stratification according to various tumor stages, endpoints, and the use of G-CSF.Conclusions: Our results which, based on a cohort study, indicate that CIN is associated with improved survival in patients with colorectal cancer. However, further randomized controlled trials are warranted.