The long-term risk of malignancy following a diagnosis of coeliac disease or dermatitis herpetiformis: a cohort study.

BACKGROUND: People with coeliac disease are known to be at increased risk of malignancy; however, long-term risks of malignancy beyond 10-15 years are largely unstudied. AIM: To estimate how long an increased risk of malignancy among coeliac disease patients persists following diagnosis and treatment, using data from a cohort with an average follow-up of 25 years. METHODS: People with coeliac disease diagnosed in the Lothian region of Scotland, United Kingdom, were followed up from January 1970 or the date of coeliac disease diagnosis (whichever was later) until the first occurrence of death, emigration, cancer diagnosis or the end of 2004. Standardised incidence ratios were calculated to compare the cancer incidence rates among this group with those from the population of Scotland. RESULTS: Overall, the risk of any malignancy in coeliac disease patients compared with the general population was increased 40% [standardised incidence ratio (SIR) = 1.41; 95% CI 1.09-1.78]. An increased risk for cancer overall persisted for up to 15 years, beyond which no overall increase in malignancy risk was observed, although the risk of non-Hodgkin's lymphoma remained raised beyond 15 years (SIR = 5.15; 95% CI 1.40-13.2). In total, there were 14 non-Hodgkin's lymphomas in the cohort, providing an overall incidence of 1.3 per 1000 person-years. CONCLUSIONS: The overall risk of malignancy in coeliac patients declines with time after diagnosis and is not significantly increased after 15 years. Most of the increased risk can be attributed to the development of haematological malignancies, despite their very low absolute rate of occurrence.