The prognostic impact of neutrophil-to-lymphocyte ratio, lymphocyte-to-monocyte ratio, and platelet-to-lymphocyte ratio in patients with advanced colorectal cancer treated with first-line chemotherapy

Introduction
Colorectal cancer is the second most frequently diagnosed malignancy and one of the leading causes of cancer-related death in Poland. Many reports of different types of cancer have indicated that blood count parameters may serve as a source of prognostic or predictive information.

Aim
To assess the association between these parameters and clinical outcome in patients with advanced colorectal cancer.

Material and Methods
We retrospectively analysed a database of 295 patients with advanced colorectal cancer treated with first-line palliative chemotherapy at our institution from January 2008 to December 2012. Blood-based parameters were measured before the first cycle of treatment.

Results
The median progression-free survival (PFS) was 6.7 months, and the median overall survival was 17.6 months. A high neutrophil-to-lymphocyte ratio (NLR) and a high platelet-to-lymphocyte ratio (PLR) were associated with a shorter survival (hazard ratio (HR): 1.88, p < 0.0001 for the NLR and HR: 1.39, p = 0.0054 for the PLR), but for the PLR, we observed only a not significant trend toward a worse PFS (HR = 1.25, p = 0.07 for the PLR and HR = 1.55, p = 0.0004 for the NLR). A high lymphocyte-to-monocyte ratio (LMR) was associated with a better prognosis (HR = 0.58, p ≤ 0.0001) and a longer PFS (HR = 0.73, p = 0.011).

Conclusions
The blood-based parameters are readily available, reliable, and low-cost biomarkers, which can be easily incorporated into routine practice to predict the prognosis in patients with advanced colorectal cancer.