Background: Many studies showed an association between absolute neutrophil count (ANC), absolute monocyte count (AMC), neutrophil-lymphocyte ratio (NLR), monocyte-lymphocyte ratio (MLR), and platelet-lymphocyte ratio (PLR) with poor overall survival (OS) in patients with cancer. However, only a few studies were conducted to further investigate this association in colorectal cancer (CRC).
Methods: Clinical data from 299 stage IV CRC patients treated at King Hussein Cancer Center from 2004 to 2012 have been retrospectively reviewed. We examined the association between ANC, AMC, MLR, PLR, and NLR with lung metastasis in stage IV CRC. Receiver Operating Characteristic (ROC) curve analysis was operated to determine the optimal NLR cutoff value. Univariate and multivariate analysis were performed.
Results: The ROC value of 3.4 was determined as the cutoff value of NLR to study the association. Univariate and multivariate analysis showed that patients with high baseline NLR (≥ 3.4) had more baseline lung metastasis than patients with low NLR (< 3.4) (p = 0.0001, p = 0.0151, respectively). Also, baseline NLR correlated significantly with the presence of lymphovascular invasion (p = 0.001). In patients with no baseline lung metastasis, high post-treatment NLR was associated with consequent development of lung metastasis (p = 0.0227). Other markers including ANC, AMC, MLR, and PLR were significantly associated with lung metastasis at time of diagnosis (p = 0.0006, p = 0.0006, p = 0.0187, and p = 0.001, respectively).
Conclusion: Results are suggesting that different hematologic markers obtained from a cheap test (CBC) could potentially be used to predict the likelihood of lung metastasis in stage IV CRC. Prospective studies are needed to further assess the immune cells' role in tumor metastasis promotion.
Keywords: Colorectal cancer; Lung metastasis; Neutrophil-lymphocyte ratio; Stage IV.