Diagnostic and Prognostic Utility of Lymphocyte-to-Monocyte Ratio and Hemoglobin-to-Platelet Ratio in Colorectal Cancer: A Cross-Sectional Study in Iraq

Abstract

Background: Colorectal cancer (CRC) is a major global health burden, the third most common cancer, and the second leading cause of cancer-related deaths. Chronic inflammation is the key driver of its pathogenesis. Although colonoscopy is the diagnostic gold standard, its limitations necessitate the use of noninvasive biomarkers. Inflammation-based ratios, such as the Lymphocyte-to-Monocyte Ratio (LMR) and Hemoglobin-to-Platelet Ratio (HPR), are derived from routine blood tests. Objective: This study evaluated the diagnostic value of LMR and HPR, both individually and in combination, for early detection of CRC in an Iraqi cohort. We further assessed their association with histopathological tumor features (tumor stage, grade, lymph node involvement, and metastasis) and disease stage. Materials and Methods: A cross-sectional study was conducted from September 2024 to April 2025, involving 60 newly diagnosed, treatment-naive CRC patients (stages I-IV) from hospitals in Hilla, Karbala, and Al-Najaf, Iraq. Patients with significant comorbidities, prior anti-cancer treatment, or recent transfusions were excluded. Complete Blood Count (CBC) analysis (using ADVIA 2120i) was used to calculate LMR and HPR. Associations with clinicopathological features were analyzed using t-tests, ROC analysis, and multivariate regression. Results: Decreased LMR and HPR were significantly associated with advanced disease. Lower LMR was correlated with lymph node metastasis (N0 vs. N+: p=0.03) and advanced clinical stage (I/II vs. III/IV, p=0.037). Lower HPR was correlated with deeper tumor invasion (T1+T2 vs. T3+T4: p=0.046), lymph node metastasis (N0 vs. N+: p=0.04), advanced clinical stage (I/II vs. III/IV: p=0.0033), and distant metastasis (M0 vs. M1, p=0.005). ROC analysis showed that HPR had a higher diagnostic accuracy for distinguishing early (I/II) from advanced (III/IV) stages (AUC=77%, sensitivity =65%, specificity =88% at cut-off >0.5) than LMR (AUC=65%, sensitivity =84% at cut-off >3.3). Multivariate regression confirmed that LMR (β=−0.43, p=0.016) and HPR (β=−4.94, p=0.005) were significant independent inverse predictors of advanced-stage disease. Conclusion: This study revealed that LMR and HPR are readily accessible, low-cost inflammatory biomarkers inversely associated with advanced colorectal cancer progression in Iraqi patients. Decreased levels of both ratios, particularly HPR, correlated significantly with adverse histopathological features (lymph node metastasis, deeper invasion, advanced TNM stage, distant metastasis) and demonstrated moderate diagnostic utility for identifying advanced disease.