Risk for colorectal adenocarcinoma in pernicious anemia. A population-based cohort study.
OBJECTIVE
To determine the long-term risk for colorectal cancer among patients with pernicious anemia.


METHODS
Historical cohort study.


METHODS
Population-based inception cohort of Rochester, Minnesota, residents.


METHODS
We identified 150 Rochester residents who had the onset of pernicious anemia during the 30-year period from 1950 through 1979, and we followed this cohort for 1664 person-years of observation. The observed risk for subsequent colorectal cancer in the cohort was compared with that expected based on incidence rates of colon and rectal cancer for the local population.


RESULTS
There were 14 cases of colorectal cancer among the 150 patients with pernicious anemia (where 10.5 cases were expected), and 9 of these cases were found after the diagnosis of pernicious anemia was established (where 5.1 cases were expected). The relative risk for colon cancer at any time after the diagnosis of pernicious anemia was 1.8 (CI, 0.8 to 3.3). The relative risk was greatest (4.1; CI, 1.7 to 8.7) in the 5-year period immediately after the diagnosis of pernicious anemia; during this period, 7 cases of colon cancers were observed but only 1.7 were expected (P less than 0.0001).


CONCLUSIONS
Although the overall risk does not achieve statistical significance, patients with pernicious anemia may have an increased risk for colorectal adenocarcinoma in the 5 years after diagnosis.
Talley
N J
NJ
Mayo Clinic, Rochester, Minnesota.
Chute
C G
CG
Larson
D E
DE
Epstein
R
R
Lydick
E G
EG
Melton
L J
LJ
D000230:Adenocarcinoma / Q000453:epidemiology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000752:Anemia, Pernicious / Q000150:complications*; D015982:Bias; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000453:epidemiology*; D016001:Confidence Intervals; D005260:Female; D005755:Gastrins / Q000097:blood; D006801:Humans; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D012306:Risk; D013997:Time Factors
D005755:Gastrins