Anemia can predict the prognosis of colorectal cancer in the pre-operative stage: a retrospective analysis

BACKGROUND: Early detection of colorectal cancer (CRC) improves prognosis, yet many CRCs are diagnosed following symptoms. The aim of this study was to determine which CRC-related symptoms or signs can predict an advanced CRC in the pre-operative stage. METHODS: Retrospective analysis of 300 patients who underwent surgery for CRC between the years 2008 and 2019. Patients’ symptoms prior to CRC diagnosis were documented. Primary endpoint was the association of signs or/and symptoms with CRC diagnosis at TNM stages of 2–4 (i.e., highly advanced), compared to TNM score of 0–1 (i.e., locally advanced). RESULTS: Three hundred patients, 91 with locally advanced and 209 with highly advanced CRC, were enrolled. There was a significant correlation between highly advanced CRC, compared to locally advanced, regarding tumor size (4.8 vs. 2.6 cm, p<0.001), presentation of any symptom prior to diagnosis (77% vs. 54%, p<0.001), anemia (46% vs. 29%, p=0.004), and severe anemia (17% vs. 4%, p=0.002). Mean hemoglobin was 12.2 ± 2.2 and 13.1 ± 1.8 in the highly advanced compared to locally advanced CRC, respectively, p<0.001. Anemia correlated with the T stage of the tumor: 21% of patients diagnosed at stages 0–1 had anemia, 39% at stage 2, 44% at stage 3, and 66% at stage 4 (p=0.001). CONCLUSIONS: Anemia is the only finding that correlates with highly advanced CRC, in the pre-operative stage. When CRC has been diagnosed, the presence of anemia, at any level, may be considered in determining prognosis at the pre-operative stage. Physicians should be aware that when anemia is present, the risk for highly advanced CRC increases, and therefore should pursue with CRC detection.