Introduction: baseline neutrophil-to-lymphocyte ratio (NLR) at the time of colorectal cancer (CRC) diagnosis has been proposed as a predictor of long-term survival. The aim of this study was to analyze its usefulness in a homogeneous population with control of the main confounding factors.
Methodology: observational study of 836 patients who underwent surgery for CRC. Patients were divided into two groups: NLR ≤ 3.3 vs NLR > 3.3. To control for confounders, they were matched one-to-one by propensity analysis. A final cohort of 526 patients was included in the study.
Results: the two groups were mismatched in terms of age, comorbidity, tumor stage, rectal location, and neoadjuvant therapy. Once matching was performed, baseline NLR was statistically significantly associated with long-term survival (p < 0.001) and behaved as an independent prognostic factor for survival (p = 0.001; HR: 1.99; 95 % CI: 1.32-3.00) when adjusted in a Cox regression model using age (p < 0.001; HR: 1.04; 95 % CI: 1.02-1.06) and the Charlson Comorbidity Index (p < 0.001; HR: 1.40; 95 % CI: 1.27-1.55). Neoadjuvant therapy lost its statistical significance (p = 0.137; HR: 1.59; 95 % CI: 0.86-2.93).
Conclusions: a high baseline NLR (> 3.3) in patients with colorectal cancer at diagnosis represents a poor prognostic factor in terms of survival. Its use in routine practice could intensify therapeutic strategies and follow-up in these patients.