The value of red blood cell distribution width in diagnosis of patients with colorectal cancer

Background: Red blood cell distribution width (RDW) is a parameter of standard full blood count tests that reflects the size variability of erythrocytes In recent studies, RDW levels have been associated with ischemic heart disease, acute and chronic heart failure, hypertension, and inflammatory bowel disease. However, it is unclear whether RDW is associated with colorectal cancer.

Methods: Eighty-five patients were diagnosed with colorectal cancer. Fifty-four other patients each diagnosed with colon polyps during the same period served as the control group. The patients were classified according to the seventh edition of the AJCC Cancer Staging Manual of 2009 into groups of different cancer stages, and simultaneously divided into groups with or without metastasis. The multigroup metering data was tested by a non-parametric Kruskal-Wallis H test, and the two subsets of patients formed above were compared using a Mann-Whitney U test. The association between continuous variables was assessed by Spearman correlation analysis while the association between RDW and colorectal cancer metastasis was estimated by receiver operating characteristic (ROC) curve analysis.

Results: Increased RDW was observed in patients with colorectal cancer. The RDW was significantly different for each subgroup of colorectal cancer as follows: stage III + IV > stage III, T3 + T4 > T1 + T2, N1 + N2 > N0, and M1 > M0 (P < 0.05). The area under the receiver-operating characteristic curve of the RDW in the diagnosis of colorectal cancer metastasis was 0.721 (95% confidence interval of 0.612-0.831).

Conclusions: The value of RDW is closely related to colorectal cancer metastasis.