asbestos--amosite and Colonic-Neoplasms

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.

Topics: Asbestos; Asbestos, Amosite; Asbestos, Serpentine; Colon; Colonic Neoplasms; Foreign Bodies; Humans; Microscopy, Electron; Occupational Diseases

A cohort of 820 men in a Paterson, New Jersey, amosite asbestos factory which began work during 1941-1945 was observed from 5 to 40 years after start of work. Most of the cohort had limited duration of work experience (days, weeks, months), though some men worked for several years until the factory closed in 1954. With white males of New Jersey as the control population, Standardized Mortality Ratios (SMRs) of 500 are evident for the cohort for lung cancer and for noninfectious pulmonary diseases (including asbestosis), while being almost 300 for total cancer and about 170 for all causes of death. A statistically significant SMR of almost 200 is seen for colon-rectum cancer. Mesothelioma incidence initially shows a strong relationship with advancing time since onset of exposure and then tails off. The main concern of the study is with dose-response patterns. Response is measured by the mortality for relevant causes of death, while the direct asbestos dosage was measured in two ways. One way was the length of time worked in the factory and the other was the individual's accumulated fiber exposure, calculated by multiplying the aforementioned length of time worked by the estimated fiber exposures associated with the particular job that the worker had in the factory. Whichever measure of dosage is used, it was found that, in general, the lower the dose, the longer it took for adverse mortality to become evident and, also, the smaller the magnitude of that adverse mortality.

Topics: Adult; Asbestos; Asbestos, Amosite; Colonic Neoplasms; Dose-Response Relationship, Drug; Humans; Lung Diseases; Lung Neoplasms; Male; Mesothelioma; Middle Aged; New Jersey; Occupational Diseases; Rectal Neoplasms; Risk; Time Factors