RESUMO
BACKGROUND: Cancer-related fatigue (CRF) is a frequent symptom in colorectal cancer survivors. It is unknown to what extent anemia may contribute to CRF in colorectal cancer survivors. This study aimed to investigate the association between hematocrit, as marker for anemia, and CRF among colorectal cancer survivors from diagnosis until two years thereafter. METHODS: The study population included 1,506 newly diagnosed colorectal cancer survivors at any stage of disease from a prospective cohort study. Hematocrit and CRF (EORTC QLQ-C30) were assessed at diagnosis, six months, and two years after diagnosis. Multivariable logistic regression or multivariable linear mixed models were used to assess the associations of hematocrit with CRF prevalence, or CRF severity over time, respectively. RESULTS: A low hematocrit (levels <40% men/<36% women) was present in a third of the survivors at diagnosis and six months thereafter, and among 16% two years after diagnosis. The prevalence of CRF was 15% at diagnosis, peaked at 27% at six months, and was 14% two years after diagnosis. Hematocrit was associated with the prevalence of CRF at diagnosis [OR, 0.92; confidence interval (CI), 0.88-0.95], 6 months (OR, 0.89; 95% CI, 0.86-0.92), and 2 years (OR, 0.91; CI, 0.87-0.96) after diagnosis. Lower hematocrit was associated with higher severity of CRF over time (beta-coefficient = 1.3; CI, 1.5-1.1). CONCLUSIONS: Lower hematocrit levels were longitudinally associated with a higher prevalence and severity of CRF in colorectal cancer. IMPACT: Our findings emphasize the importance of long-term anemia monitoring and a potential role of anemia in CRF among colorectal cancer survivors.