Variations in hemoglobin before colorectal cancer diagnosis

We have conducted the present case-control study to examine whether long-term variations in blood hemoglobin (Hb) levels within the normal range could detect subtle gastrointestinal bleeding in the early development of colorectal cancer (CRC). A total of 1074 CRC cases aged 45-75 years that have been diagnosed with CRC and had normal Hb levels were frequency matched for age and sex with cancer-free individuals at a ratio of 10 controls per case. Our retrospective analysis indicates that starting from 4 years prior to cancer diagnosis, a progressive significant (P < 0.001) decrement in Hb levels (0.28 g/dl per 6 months) was found among cases but not among controls. CRC patients were characterized in an on-going, long-term, logarithmic decrement in Hb levels. Such small changes within the normal Hb range could be missed by health providers, but automatically detected by computerized alert algorithms.. European Journal of Cancer Prevention 19: 342-344 (C) 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins.