Neo-adjuvant Chemotherapy-Induced Neutropenia Is Associated with Histological Responses and Outcomes after the Resection of Colorectal Liver Metastases

Background Neutropenia, the major adverse event in chemotherapy, is associated with favourable clinical outcome in several solid tumours. We aimed to investigate the predictive value of neo-adjuvant chemotherapy (NAC)-induced neutropenia for the pathological response and prognosis in colorectal liver metastases (CRLM) patients. Methods A retrospective review was performed in 141 CRLM patients receiving NAC followed by liver resection. A logistic regression was applied to analyse potential predictors. A Cox proportional hazards analysis was used to analyse survival. Results Neutropenia due to NAC was observed in 42.6% (60/141) of all patients, and grade 3/4 neutropenia was noted in 31.7% (19/60). A pathological response (tumour regression grade (TRG) 1-3) was reported in 46.1% (65/141) of patients. Multivariate analysis showed that neutropenia significantly predicted the favourable pathological response (OR = 3.718, 95% CI 1.716-8.329, P = 0.001), as well as targeted therapy, good differentiation and preoperative CEA < 10 ng/ml as independent predictors of favourable histological response. Of the patients, 54.6% (77/141) had postoperative complications, including 28 major complications (28/77, 36.4%). Severe neutropenia significantly predicted postoperative major complications in multivariate analysis (OR = 4.077, 95% CI 1.184-14.038, P = 0.026). Compared to patients without neutropenia, patients with neutropenia had significantly better progression-free survival (PFS) (P = 0.007; mPFS, 10.2 months vs. 6.7 months). Patients with histological response had significantly better PFS than patients with no histological response (P = 0.001; mPFS, 10.0 months vs. 5.5 months). According to multivariate analyses, neutropenia was a significant predictor for better PFS (HR = 0.613, 95% CI 0.406-0.925, P = 0.020) but not OS. Conclusions For CRLM patients receiving NAC followed by liver resection, NAC-induced neutropenia was a significant predictor of favourable pathological response, postoperative major complications and better prognosis, which makes it useful for CRLM patients in guiding treatment approaches and prognosis assessments.