Low incidence of colorectal cancer in patients with rheumatoid arthritis.
OBJECTIVE
Aspirin (ASA) and also nonsteroidal anti-inflammatory drug (NSAID) use has been associated with a low incidence of colorectal cancer. The incidence of colorectal cancer in a cohort of patients with rheumatoid arthritis (RA) is reported here.


METHODS
Cancer incidence was studied in a cohort of 9469 persons hospitalized for RA during 1970-1991 in Finland. The follow-up time was about 65,400 person-years.


RESULTS
The incidence of colon cancer was significantly lower than in the general population [standardized incidence ratio (SIR) 0.57; 95% confidence interval (CI) 0.33-0.93], and the combined SIR for colorectal cancer was 0.62 (95% CI 0.42-0.88), while the combined incidence of all malignancies (SIR 1.16; 95% CI 1.07-1.26) was higher in RA patients than in the general population.


CONCLUSIONS
Chronic use of NSAIDs or ASA, including antiinflammatory doses, is probably the main explanation for the low incidence of colorectal cancer in RA patients.
Kauppi
M
M
Rheumatism Foundation Hospital, Heinola, Finland.
Pukkala
E
E
Isomäki
H
H
D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000150:complications*; D001241:Aspirin / Q000627:therapeutic use*; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000150:complications / Q000453:epidemiology*; D005260:Female; D005387:Finland; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged
D000894:Anti-Inflammatory Agents, Non-Steroidal; D001241:Aspirin