Is anaemia relevant in the referral and diagnosis of colorectal cancer?

OBJECTIVE: Current efforts to improve the outcome from colorectal cancer aim to shorten the delay between referral and diagnosis. Investigation of iron-deficiency anaemia has a high yield for the diagnosis of gastrointestinal malignancy and its presence is included in current referral guidelines. We explored the relationship between anaemia and colorectal cancer.
METHOD: We reviewed hospital and laboratory database records of patients diagnosed with colorectal cancer between January 2003 and June 2004. The site of colorectal cancer was correlated with the presence of anaemia at the time of referral. Anaemia was defined according to local practice (Hb < 12.0 g/dl in females and <13.0 g/dl in males), compared with the threshold recommended in current national referral guidelines (Hb < 10 g/dl in females and <11 g/dl in males).
RESULTS: Over 18 months, 143 patients were diagnosed with colorectal cancer. Anaemia was present in 48% of males and 50% of females using local practice and 24% of males and 16% of females using national referral guidelines. Those with right-sided and non-rectal cancers were significantly more likely to be anaemic than those with left-sided and rectal cancers, respectively.
CONCLUSION: In approximately half of cases the diagnosis of colorectal cancer is not associated with anaemia. Anaemia is more common with proximal lesions but this is not a consistent finding. The current threshold for anaemia at which national guidelines suggest referral also appears to be insensitive.