Background: Colorectal cancer (CRC) is the third most common cancer and it is a worldwide challenge. Neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) had been suggested as markers of CRC, but the role of monocyte-to-lymphocyte ratio (MLR) in CRC patients before surgery and chemotherapy is unclear. The study aimed to compare the diagnosis and prognosis value of MLR, NLR, and PLR in CRC.
Methods: A retrospective study was conducted on 783 patients with histologically conﬁrmed colorectal cancer between 2015 and 2017 in Fujian Medical University Union Hospital. A total of 1,232 healthy age-matched participants were eligible for the study. Receiver-operating characteristic (ROC) analysis was performed to compare the area under the ROC curve (AUC) of MLR, NLR, PLR, carcinoembryonic antigen (CEA), and carbohydrate antigen 19-9 (CA19-9). Furthermore, chi-squared test was conducted to determine the prognostic values of MLR, NLR, and PLR.
Results: The levels of MLR, NLR, and PLR in CRC patients were significantly higher than those in 1,232 healthy participants. The area under the ROC curves (AUCs) of MLR, CEA, PLR, NLR, and CA19-9 were 0.739, 0.726, 0.683, 0.610, and 0.603, respectively. Moreover, the combined marker of CEA + MLR with an AUC of 0.815 acted as a superior diagnostic marker compared to the other combined markers, including the combined marker of CEA + CA19-9. Furthermore, the level of MLR was associated with tumor size (p = 0.001), and a high level of NLR was significantly correlated with pT stage (p = 0.048) and tumor size (p = 0.004).
Conclusions: The present study shows for the first time that MLR rather than NLR and PLR is the better diagnostic marker for colorectal cancer, and NLR may be a better prognostic marker for CRC patients.