Agricultural herbicide use and risk of lymphoma and soft-tissue sarcoma.

A population-based case-control study of soft-tissue sarcoma (STS), Hodgkin's disease (HD), and non-Hodgkin's lymphoma (NHL) in Kansas found farm herbicide use to be associated with NHL (odds ratio [OR], 1.6; 95% confidence interval [CI], 0.9, 2.6). Relative risk of NHL increased significantly with number of days of herbicide exposure per year and latency. Men exposed to herbicides more than 20 days per year had a sixfold increased risk of NHL (OR, 6.0; 95% CI, 1.9, 19.5) relative to nonfarmers. Frequent users who mixed or applied the herbicides themselves had an OR of 8.0 (95% CI, 2.3, 27.9) for NHL. Excesses were associated with use of phenoxyacetic acid herbicides, specifically 2,4-dichlorophenoxyacetic acid. Neither STS nor HD was associated with pesticide exposure. This study confirms the reports from Sweden and several US states that NHL is associated with farm herbicide use, especially phenoxyacetic acids. It does not confirm the case-control studies or the cohort studies of pesticide manufacturers and Vietnam veterans linking herbicides to STS or HD.

Screening for colorectal cancer and polyps among pattern makers.

In response to a union request, a cancer screening program was conducted for the Pattern Makers' League of North America. Ten colon cancer cases were detected among the 1,465 white men screened with a flexible sigmoidoscope. The difficulties in obtaining appropriate "expected" numbers were that prevalent detectable preclinical colon cancer is not equivalent to incident disease, and the flexible sigmoidoscope yields results not directly comparable to those of the rigid sigmoidoscope used previously. The "expected" number of cancers was obtained by using an independent estimate of 5 years for the mean duration of the detectable preclinical phase. This implied that the expected number of colon cancer cases should be based on the age-specific incident rates among white men in the next-older 5-year age group and that the annual expected number should be multiplied by five. Therefore, the ten observed cases of colon malignancies represented an approximately threefold increase. For invasive cancer only, there was a slightly less than twofold cancer increase. Fifteen percent of the men had one or more colorectal polyps.

Sensitivity of fecal hemoccult testing and flexible sigmoidoscopy for colorectal cancer screening.

Fecal Hemoccult testing and flexible sigmoidoscopy have been proposed as means of screening for colorectal cancer in the general population, as well as in identified high-risk groups. A colorectal cancer screening program was conducted for the Pattern Makers' League of North America. A total of 1,473 white males were screened with fecal Hemoccult testing and flexible sigmoidoscopy during the period 1981 to 1983. The fecal Hemoccult test after diet restriction was positive in 38 workers (2.6%). Among 12 colorectal cancers, including in situ cases, only three were positive by this test. The sensitivity of this test for picking up cancer is only 25%. The positive predictive value was 7.9%. It is concluded that the Hemoccult test for the detection of colorectal cancer and polyps is not a valuable tool because of low sensitivity, whereas flexible sigmoidoscopy has a significant role in colorectal cancer screening of an asymptomatic population at risk.

Comparison of crude and smoking-adjusted standardized mortality ratios.

To systematically evaluate bias in estimating relative risks associated with occupational exposures obtained in the absence of smoking data, the authors compared crude and smoking-adjusted standardized mortality ratios for selected occupations using data from a study of U.S. veterans. Crude and smoking-adjusted SMRs were highly correlated: lung cancer (r = .88), bladder cancer (r = .98), and intestinal cancer (r = .97). Greater differences occurred for lung cancer, which is more strongly related to smoking than bladder or intestinal cancer.

Second cancer following cancer of the digestive system in Connecticut, 1935-82.

The risk of developing a second primary cancer was evaluated in approximately 64,000 persons diagnosed with cancer of the digestive system in Connecticut during 1935-82. Significant excesses of all second cancers combined were observed following cancer of the esophagus (58 observed vs. 33 expected), small intestine (41 vs. 24), and colon (2,268 vs. 1,714). A slight excess of multiple primaries was observed following cancer of the liver and biliary tract (47 vs. 40). The observed number of second cancers was nearly equal to the expected number for persons initially diagnosed with cancers of the stomach (251 vs. 258), rectum (952 vs. 941), and pancreas (40 vs. 40). Persons with initial cancers of the small intestine, colon, and rectum also had excess second cancers arising primarily in the colon, which suggested the influence of common etiologic factors or possibly misclassified metastases in some. Shared dietary, socioeconomic, or hormonal factors may explain the excess of uterine and ovarian cancers among patients with colon cancer and the excess of breast cancer among patients with colon and rectal cancers. Oral and respiratory cancers occurred more frequently than expected in persons with an initial esophageal cancer, which is likely due to common risk factors of cigarette smoking or alcohol intake, or both. The elevations in cancer of the prostate among males with cancers of the esophagus, small intestine, colon, rectum, liver/biliary, and pancreas are probably artifacts associated with increased medical surveillance of cancer patients. The prostate cancer excesses were limited to the first year after diagnosis of the initial cancer or decreased over time for all but cancer of the colon and small intestines. Increased medical surveillance may also contribute to the excess renal and bladder cancers seen within 5 years of diagnosis of stomach cancer. Excesses were also seen for second pancreatic cancer among small intestine and liver/biliary cancer patients and second kidney and brain cancers among those with colon cancer. The deficits of stomach and rectal cancer among persons initially diagnosed with the same tumors, respectively, were anticipated because surgical removal of the organ is the primary form of treatment. Patients with rectal cancer also had deficits of stomach and pancreatic cancers. Future research should clarify the role of diet, alcohol, metabolic and endocrine factors, and host susceptibility on the risk of second neoplasms following cancer of the digestive system.

Prevalence of colorectal polyps among Michigan pattern and model makers.

A group of 902 pattern and model makers were screened for colorectal cancer and polyps using a 60-cm flexible sigmoidoscope. Three recent mortality studies have found a significant excess of colorectal malignant neoplasms in this occupational group. Four adenocarcinomas, two carcinoids, and two cancers in situ were found. In addition, 150 (17%) of the individuals were found to have polyps. Among white males 40 to 70 years of age, the prevalence rate was found to be 23%. The prevalence of colorectal polyps among the pattern and model makers was compared with that of four previously studied asymptomatic populations who were also examined using a 60-cm flexible sigmoidoscope. Polyp rates were found to be significantly greater among pattern and model makers than among three of the four comparison populations. The odds ratios between these three populations and the study population ranged from 1.9 to 2.7 and closely approximate the ratios found in previous studies evaluating colon cancer in this occupational group.

Monographs on human exposures to chemicals in the workplace.

The National Cancer Institute has contracted with Syracuse Research Corporation to produce monographs on the potential hazards of human exposure to approximately 70 chemicals used in the workplace. The monographs include detailed exposure data for specific job categories, as well as summaries of chemical and physical data, animal and human toxicological studies, short-term assays, and epidemiologic data. The information is useful for identifying suitable populations for epidemiologic research.

Causes of death among female chemists.

A mortality odds ratio analysis of cause of death among 347 White female members of the American Chemical Society (ACS) revealed a five-fold excess of suicide, notably by cyanide poisoning. Risk was also elevated for all cancers combined and for cancers of the breast, ovary, stomach, pancreas, and lymphatic and hematopoietic system. The excess breast and ovary cancer deaths were limited to unmarried women.

Truck driving and bladder cancer mortality in rural New England.

The relationship between truck driving and bladder cancer mortality was investigated in a case-control study in New Hampshire and Vermont. In-person interviews were conducted with the next-of-kin of 325 bladder cancer cases and 673 controls who died during 1975-79. There were 35 cases and 53 controls who had ever been employed as truck drivers [odds ratio (OR)=1.5, 95% confidence interval (CI)=0.9, 2.6]. There was a statistically significant, but inconsistent, positive association between number of years of truck driving and the OR's, rising to 2.3 (1.2,4.1) for 5 years or more of truck driving. Risk was greatest in men who began driving in the 1930's and 1940's (OR=2.6, 95% CI=1.3,5.1) and among residents of two of the most urbanized counties (OR=3.0, 95% CI=1.2,7.4). The association of bladder cancer with truck driving was unaffected by control for possible confounding factors, such as cigarette smoking and coffee drinking. It was not possible to determine whether the risks associated with truck driving were specifically due to diesel fumes. Truck drivers reporting diesel exposures had an OR=1.8 (95% CI=0.5,7.0), but those without diesel exposure still had an OR=1.5 (95% CI=0.8,2.7). Twenty-six cases and 39 controls reported exposure to diesel emissions in any occupation (OR=1.5, 95% CI=0.8,2.8), and a significant duration-response relationship was seen, rising to threefold for those employed in such jobs for 30-39 years.

Death certificate case-control study of cancers of the prostate and colon and employment in the textile industry.

A case-control study was conducted to investigate possible relationships between employment in the textile industry and cancers of the prostate and colon. Death certificate information on occupation and industry was obtained for 1037 male prostatic cancer cases, 820 male and female colon cases, and matched controls who died during 1970-1978 in South Carolina. Black males were the only race-sex group to show an excess risk of prostate or colon cancer among employees of the textile industry. Nonstatistically significant excesses of prostate cancer were seen in dyeing and finishing businesses and broad woven fabric mills. Overall, there was no strong evidence indicating a relationship between the textile industry and either prostate or colon cancer. It is unlikely that limitations of the data masked real risks since previously reported associations with nontextile industries were confirmed.

Grouping occupations according to carcinogenic potential: occupation clusters from an exposure linkage system.

An occupational clustering scheme has been developed from an occupation and exposure linkage system. In this scheme, occupational titles are grouped together hierarchically according to the numbers and degrees of their shared exposures. The use of the clusters obtained from this hierarchy is demonstrated in the analysis of the data from a case-control study of bladder cancer.

A retrospective cohort study of mortality and cancer incidence among chemist.

This retrospective cohort study examines mortality and cancer incidence among 3,686 men and 75 women who were employed as chemists in 1959. During the period 1964 to 1977, the male chemists experienced lower overall mortality than other salaried employees of the chemical company (198 deaths observed, 241.0 expected, SMR = 82). Large deficits are seen in lung cancer and arteriosclerotic heart disease death. The chemist appear to be at slightly higher risk for death from malignancies of the colon (12 observed, 6.7 expected, SMR = 178) and from cerebrovascular disease (15 observed, 10.8 expected, SMR = 138). The low overall mortality resulted in a larger than expected proportion of deaths due to cancer. Fewer than expected cases were diagnosed of cancer of all sited combined (61 observed, 86.5 expected, SIR = 71) and of the lung (8 observed, 20.0 expected, SIR = 40). The incidence rates of melanoma and of cancer of the prostate are slightly higher than expected, relative to the Third National Cancer Survey and the experience of nonchemists, respectively. Among female chemists, deaths due to all causes and suicide occurred more frequently than expected. Possible explanations for the lack of anticipated excess risks and for the observed deficits are presented.

A retrospective cohort study of disability among chemists.

This retrospective cohort study examines disability among 3,686 men and 75 women who were employed as chemists in 1959 and who were followed through 1977. Overall, the chemists experienced fewer absences of eight or more consecutive days than expected on the basis of the experience of other salaried employees of the chemical company. Among the men, fewer claims than expected were observed for absences due to benign and unspecified neoplasia, heart disease, and peptic ulcer, and to diseases of the urinary system, bones and joints, and skin. Also, the chemist had lower than expected incidence rates of first myocardial infarction (90 observed, 149.8 expected). The deficits may be attributable to exposure misclassification or to confounding by smoking or socioeconomic status. A slight excess was seen of absences due to mental disorders.

An occupation and exposure linkage system for the study of occupational carcinogenesis.

Studies of the adverse effects of occupational exposures are most informative when jobs can be classified according to the specific chemical or physical agents involved. However, information sufficiently detailed to permit this is not often available. In such instances a study usually will be based on subjects classified according to industry or task, effectively ignoring the specific agents to which exposure occurred. Such crude classification tends to reduce or obscure associations between specific exposures and disease. In response to this problem, the authors have developed an occupation and exposure linkage system with particular reference to carcinogenesis. Occupations were classified by industry and by task within the industry. Lists of suspect carcinogens were developed and each suspect carcinogen was linked to industries and tasks in which it has been used. These links make it possible to place in the same exposure category all study subjects whose employment history suggests contact with a particular agent. Epidemiologic analysis then can be based on chemical and physical exposures, rather than on industries or tasks. The linkage system enhances the value of information on occupation obtained from death certificates, cancer registries, medical records, and questionnaires.