Carcinoma of the colon in asbestos‐exposed workers: Analysis of asbestos content in colon tissue

Epidemiological studies have indicated an increased incidence of carcinoma of the colon in asbestos workers. The present study evaluated the colon tissue asbestos burden, by light and electron microscopic analytic techniques, in patients with a history of occupational asbestos exposure and colon cancer. Asbestos fibers and/or asbestos bodies were present in colon tissue from 14 of 44 (31.8%) asbestos workers with colon carcinoma (range 142,199 to 15,231, 543 fibers/g/wet weight, mean 2,517,823). Chrysotile was identified in 9 patients and amosite in 3 patients. Both amosite and chrysotile were found in the colonic wall in one individual. Other forms of asbestos (e.g., crocidolite, tremolite, or anthophyllite) were not found. Asbestos fibers and asbestos bodies were not found in colon tissue from 20 control patients (colon carcinoma and no asbestos exposure). Asbestos fibers frequently enter and reside in the wall of the colon and are often intimately associated with tumor tissue at the site of colon carcinoma in workers with asbestos exposure and colon carcinoma.