Reduced incidence of rectal cancer, compared to gastric and colonic cancer, in a population of 73,076 men and women chronically immunosuppressed.
The incidence of gastric, colonic, and rectal cancers was determined in a cohort of 73,076 men and women chronically immunosuppressed after heart or renal transplantation, to test the hypothesis that there would be a reduced incidence of gastric cancer by dampening chronic gastritis secondary to infection caused by Helicobacter pylori. Follow-up was from 1-13 years. No change in the incidence of gastric cancer was found (32 cases observed, 32.86 expected). An increase in colon cancer was found (75 cases observed, 62.27 expected). A significant reduction in the incidence of rectal cancer was found (15 cases observed, 41.5 expected). This led to a chi2 of 16.92 with 1 degree of freedom, significant at the 0.1% level. The effect was greater in men than women and more marked in heart recipients than in those receiving renal transplants. This unexpected finding led to a review of experiments in mice and rats that present evidence for immune promotion of large-bowel cancers induced by carcinogens by gut-associated lymphoid tissue. We conclude that an analysis of immune function in gut-associated lymphoid tissue in the stomach, colon, and rectum in healthy and immunosuppressed patients may lead to a better understanding of immunosurveillance in the colon and immune promotion of rectal cancers.
Stewart
T
T
Ottawa General Hospital, Ottawa, Ontario, K1H 8L6 Canada. Tstewottkcan@msm.com
Henderson
R
R
Grayson
H
H
Opelz
G
G
D000818:Animals; D015331:Cohort Studies; D003110:Colonic Neoplasms / Q000453:epidemiology / Q000276:immunology*; D005260:Female; D005500:Follow-Up Studies; D016027:Heart Transplantation / Q000276:immunology; D006801:Humans; D016867:Immunocompromised Host; D015994:Incidence; D016030:Kidney Transplantation / Q000276:immunology; D008297:Male; D051379:Mice; D051381:Rats; D012004:Rectal Neoplasms / Q000453:epidemiology / Q000276:immunology*; D012727:Sex Characteristics; D013274:Stomach Neoplasms / Q000453:epidemiology / Q000276:immunology*