Red Blood Cell Distribution Width (RDW) Correlates to the Anatomical Location of Colorectal Cancer. Implications for Clinical Use

Purpose: The pathological, clinical, and therapeutic features of colorectal cancer (CRC) depend on its anatomical localization. We investigated possible associations between the red blood cell distribution width (RDW) and CRC localization. Methods: Two-hundred eighty-eight consecutive patients with CRC were retrospectively studied. Demographic, clinical, pathological and laboratory data were retrieved from clinical records and reports. Results: Median RDW values were significantly higher in patients with right-sided CRC when compared to those with CRC in other localizations (16.2, IQR: 14.5–20.0 vs 13.8, IQR: 13.0–16.1, p < 0.0001). Anisocytosis was statistically associated to haemoglobin (Hb), mean haemoglobin concentration (MHC), and mean corpuscular volume (MCV) values in all the patient groups examined. A cut-off value of 14.3% was associated with right-sided localization with sensitivity and specificity of 76.3% and 64.2%, respectively (AUC 0.71). Conclusion: Median RDW values were significantly higher in right-sided CRC when compared to other tumour locations, and may represent an additional marker for differential diagnosis.