[Rheumatoid arthritis and risk of cancer].

In the current study we linked data from the Danish Hospital Discharge Register and the Danish Cancer Registry to estimate cancer occurrence among more than 20,000 patients hospitalized at least once with rheumatoid arthritis during 1977-1987. During a follow-up interval of up to 15 years, we found increased risks of non-Hodgkin's lymphoma, Hodgkin's disease and lung cancer, while the risk of colorectal cancer was decreased. These findings were all in agreement with the results of previous studies from two other Nordic countries, which were based on a similar type of data. We also found an excess of non-melanoma skin cancer and a deficit of female breast cancer, of which only the breast cancer observation had been seen in an earlier study.