Neutrophil-to-Lymphocite Ratio (NLR) and C-reactive Protein (CRP) as New Markers in Diagnosis and Prediction of Colorectal Cancer

Colorectal cancer (CRC) is the second leading cause of cancer-related death in the Western world. Overall survival (OS) remains poor, with 50% estimated 5-year survival. In Italy, current estimates indicate that in 2020 a number of 43.700 patients have been affected by colorectal cancer, with an increasing of diagnosed cases in both men and women. It is clear that it is worthwhile to investigate the evaluation of colorectal cancer which could reflect a different spread of screening programs or be the effect of different timing in the start of the programs themselves. To improve the overall survival of colorectal cancer patients, robust biomarkers for screening and predicting disease recurrence could help identify high-risk patients, facilitate a close patient follow-up, and decide appropriate treatment regimens during the postoperative care. Colonoscopy remains the most efficient method for detecting CRC, yet its general application in the setting of screening is limited due to the uncomfortable experience and the high costs. accumulating studies have revealed the potential of systemic inflammatory markers such as C-reactive protein (CRP), albumin, neutrophils, platelets, and lymphocytes, and also biomarker combination ratios [(eg, CRP-albumin ratio (CAR), neutrophil-lymphocyte ratio (NLR), and platelet-lymphocyte ratio (PLR)] as prognostic biomarkers in different cancers, including CRC. Chronic inflammation affects all stages of tumor development. Several studies have shown that various preoperative markers reflecting systemic inflammatory response, including NLR and CRP ratio, offer predictive potential for postoperative morbidity and mortality in CRC patients. However, several issues require addressing prior to the adoption of these inflammatory markers in the clinical practice for CRC patients undergoing surgery: a) the combination of inflammatory factors that might be best in predicting oncological outcomes in colorectal cancer patients remains unclear; b) previous studies for systemic inflammatory markers have mainly interrogated their prognostic potential for oncological outcomes but have not laid emphasis for evaluating their predictive value for postoperative complications; c) there is a lack of consensus on the cut-off thresholds used for each marker for determining mortality risk resulting from surgical and oncological outcomes.