The impact of chemotherapy-associated neutrophil/ lymphocyte counts on prognosis of adjuvant chemotherapy in colorectal cancer

Abstract Background Leukocytes play an important role in cancer development. However, the impact of chemotherapy-associated neutropenia/lymphopenia on the prognosis of adjuvant chemotherapy is unknown. Here, we aimed to explore the impact of chemotherapy-associated neutrophil/lymphocyte counts on prognosis of adjuvant chemotherapy in colorectal cancer (CRC) and the risk factors for developing neutropenia/lymphopenia which showed impact on the prognosis of CRC receiving adjuvant chemotherapy. Methods From February 2003 to January 2011, 243 stage II and III CRC patients receiving adjuvant chemotherapy were enrolled in this retrospective study. The associations between neutrophil/ lymphocyte counts and disease free survival (DFS)/overall survival (OS) of CRC, and the risk factors for neutropenia/lymphopenia were investigated. Results No association of chemotherapy-associated neutrophil counts and CRC recurrence (AUC = 0.474, P = 0.534), death (AUC = 0.449, P = 0.249) was found by ROC analysis. However, the chemotherapy-associated lymphocyte counts could significantly affect CRC recurrence (AUC = 0.634, P = 0.001), or death(AUC = 0.607, P = 0.015), with a optimized cut-off of 0.66 × 109/L for recurrence, and 0.91 × 109/L for death, respectively. Kaplan–Meier method showed chemotherapy-associated lymphopenia <0.66 × 109/L was associated with shorter DFS (P < 0.0001), and chemotherapy-associated lymphopenia <0.91 × 109/L was associated with shorter OS (P = 0.003). Cox regression model showed chemotherapy-associated lymphopenia <0.66 × 109/L was the independent prognostic factor for DFS (HR, 3.521; 95%CI = 1.703-7.282), and chemotherapy-associated lymphopenia <0.91 × 109/L was the independent prognostic factor for OS (HR, 2.083; 95% CI = 1.103-3.936). Multivariate logistic regression showed the risk of developing chemotherapy-associated lymphopenia <0.66 × 109/L was found in those with pretreatment CEA ≥10 ng ml-1 (OR, 3.338; 95% CI = 1.523-7.315), and the risk of developing chemotherapy-associated lymphopenia <0.91 × 109/L was found in those with age >60 years (OR, 2.872; 95% CI = 1.344-6.136). Conclusions Chemotherapy-associated lymphopenia <0.66 × 109/L /0.91 × 109/L has a significant impact on the prognosis of CRC receiving adjuvant chemotherapy. Pretreatment CEA ≥10 ng ml-1 is the independent risk factor for developing lymphopenia <0.66 × 109/L, and age >60 years is the independent risk factor for developing lymphopenia <0.91 × 109/L during adjuvant chemotherapy of CRC.