Stomach cancer, workers exposed

In contrast, three European studies have found slight but statistically significant increases in cancer in workers exposed to trichloroethylene. A survey of Finnish workers exposed to primarily trichloroethylene found an association of limited statistical significance between exposure and incidence of stomach, liver, prostate, and lymphohematopoietic cancers (Antilla et al. 1995). However, the study did not reliably separate the effects of individual solvents, so attributing these cancers to trichloroethylene exposure alone was not possible. A significant association between workplace exposure to trichloroethylene and kidney cancer was found in a retrospective cohort study of German cardboard factory workers (Henschler et al. 1995). The... 

According to EPA (IRIS 1999), the available human epidemiological studies lack quantitative exposure data for lead and for possible confounding exposures (e.g., arsenic, smoking). Cancer excesses in the lung and stomach of lead-exposed workers that are reported are relatively small, dose-response relationships are not demonstrated neither is there consistency in the site of cancers reported. EPA (IRIS 1999) concluded that the human data are inadequate to refute or demonstrate the potential carcinogenicity of lead exposure. 

Two epidemiological studies of workers exposed to ethylene oxide revealed increased rates of leukemia. In one smdy, two cases of leukemia (0.14 expected) and three stomach cancers (0.4 expected) were observed. The other study found three cases of leukemia (0.2 expected). Because these workers had exposures to other potential carcinogens, the findings cannot be linked with certainty to ethylene oxide. The small cohort size, the small number of deaths, and uncertainties about exposure level have also been noted." A number of other studies have not found an increased rate of cancer mortality from ethylene oxide exposure. A mortality study of over 18,000 ethylene oxide workers from 14 plants producing medical supplies and foodstuffs did not find an excess of leukemia or brain, stomach, or pancreatic cancers. There was, however, an increase in non-Hodgkin lymphoma in male workers. A follow-up of 1896 ethylene oxide production workers did not find an increase in mortality from leukemia, non-Hodgkin lymphoma, or brain, pancreatic, or stomach cancers. ... 

In contrast, another study of 548 men at three lead chromate facilities showed that workers exposed at two of the facilities had a threefold excess of lung cancer. Workers at the third facility, who had zinc chromate exposure as well as lead chromate exposure, had a significant excess of lung cancer and stomach cancer. An industrial hygiene survey indicated... 

The relation between exposure to Portland cement dust and cancer was examined in a population of 546 workers who had been exposed at some time before 1974 for 1 or more years. No increased risk of overall cancer, respiratory cancer, or stomach cancer was found among the cement workers compared with a referent population. ... 

A nested case-control study within a cohort of rubber workers in the United States was performed to examine the relationship between exposure to solvents and the risk of cancer (Checkoway et al., 1984 Wilcosky et al., 1984). The cohort consisted of 6678 male rubber workers who either were active or retired between 1964 and 1973. The cases comprised all persons with fatal stomach cancer (n = 30), respiratory system cancer (z7 = 101), prostate cancer ( = 33), lymphosarcoma (n = 9) or lymphocytic leukaemia (z7 = 10). These sites were chosen because they were those at which cancers had been found to be in excess in an earlier cohort analysis (McMichael et al., 1976). The controls were a 20% age-stratified random sample of the cohort (z = 1350). Exposure was classified from a detailed work history and production records. An association was observed between exposure for one year or more to carbon tetrachloride and lymphocytic leukaemia (odds ratio (OR), 15.3 / < 0.0001, based on eight exposed cases) and lymphosarcoma (OR, 4.2 p < 0.05, based on six exposed cases) after adjusting for year of birth. The relative risk associated with 24 solvents was examined and levels of exposure were not reported. [The Working Group noted that overlapping exposures limit the ability to draw conclusions regarding carbon tetrachloride.]... 

Studies that still are inconclusive have linked ethylene oxide with leukemia and stomach cancer. It is estimated that in the United States approximately 270.000 workers are routinely exposed to ethylene oxide. Camparalively high level exposures include 96.000 persons working in hospitals ttnd an additional 21.000 persons who work in commercial medical supply sierilization facilities, as well as in the production of spices and pharmaceutical products. Since the 1950s. cthy lenc oxide has been used as a sterilizing agenl. 

Because of the possibility of confounding occupational exposure in the studies of chemical workers exposed to ethylene oxide (20,25,26,28,30-38), less weight can be given to the positive findings. Nevertheless, they are compatible with a small but consistent excess of lymphatic and hemopoietic cancers found in studies of sterilization personnel. Some of the epidemiological studies have shown an additional risk of cancer of the stomach, which was significant only in one study from Sweden (25,26,30). 

No statistically significant increase was noted based on these few cases of cancer. Among 165 production and processing workers exposed to 1,4-dioxane, 12 deaths were reported. Three of these deaths were due to cancer one stomach cancer, one alveolar carcinoma, and one mediastinal malignancy. Three deaths were not different from the expected numbers. 

Screening-level analyses suggested association between kerosene exposure and stomach cancer, but result was not confirmed by in-depth analyses screening analyses indicated that subjects with prior exposure to jet fuel (n — 43) had OR of 2.1 for colon cancer (n = 7), 2.1 for rectal cancer (n = 4), and 2.5 for kidney cancer (n = 7) in-depth analyses indicated association between jet-fuel exposure and kidney cancer (OR = 3.4) for workers exposed at substantial level (n = 6) dose-response relation observed for jet-fuel exposure and increased risk of kidney cancer... 

Cohort studies of herbicide sprayers are presented in Table V. An excess of mortality from stomach cancer was statistically significant in one small Swedish study (27). No specific malignancies were found in excess in the other studies. All had low statistical power and limited exposure assessments. The researchers had insufficient information about the types of phenoxy herbicides to which the workers were exposed and limited data about the intensity and duration of the exposures. Some phenoxy herbicides do not contain 2,3,7,8-TCDD. Corroborating results from other studies and additional observations obtained through further vital status follow-up of the cohorts may reduce the ambiguity of the results. 

In a re-evaluation of the Hanford cohort, which included approximately 28,000 male and female workers, Kneale et al. (1981) detected a significant increase in the cancers in radiosensitive tissues in workers exposed to external radiation. Radiosensitive tissues grouped together in their analyses included cancers of the stomach, large intestine, pancreas, pharynx, lung, breast, reticuloendothelial system (lymphoma, myeloma, myeloid leukemia and others), and thyroid. Approximately 50% of these cancers were in the lung however, smoking histories were not considered in the analysis. Of the male population, only 3% or 225 men had definite evidence of internal radiation. Due to this fact the authors stated that they could safely assume that the incidence of cancer from internal radiation was small compared with that associated with external radiation. 

HUMANS EXPOSED TO MATERIALS REPORTED TO BE CONTAMINATED WITH TCDD HAVE DEVELOPED CHLORACNE AND OTHER SIGNS OF SYSTEMIC POISONING. SOFT TISSUE SARCOMA HAS BEEN OBSERVED IN EXCESS AMONG WORKERS EXPOSED TO PHENOXY HERBICIDES. THESE DATA ARE INCONCLUSIVE REGARDING TCDD TOXICITY IN HUMANS BECAUSE THE POPULATIONS STUDIED HAD MIXED EXPOSURES MAKING CAUSAL RELATIONSHIPS BETWEEN EXPOSURE AND EFFECT UNCLEAR. THE DATA ARE, HOWEVER, SUGGESTIVE OF AN ASSOCIATION BETWEEN EXPOSURE TO PHENOXYACETIC HERBICIDES CONTAMINATED WITH TCDD AND EXCESS LYMPHOMA AND STOMACH CANCER. ATTEMPTS TO ASSOCIATE REPRODUCTIVE EFFECTS WITH TCDD EXPOSURE ARE INCONCLUSIVE BECAUSE OF THE INADEQUATELY DEFINED POPULATIONS STUDIED AND THE DIFFICULTIES OF DEFINING EXPOSURE. 

Stomach cancer Meta-analysis of occupationally exposed battery and smelter workers... 

Tumorigenidty The risk of death and the incidence of cancers with quantitative exposure to benzene-soluble fraction, benzo(a) pyrene, fluoride, and inhalable dust have been studied in two 4316 male prebake smelter workers using cancer incidence registries and follow-up for 20 years [35. There were smoking-adjusted monotonic relationships between the risk of respiratory cancer and cumulative inhalable dust exposure, cumulative fluoride exposure, and cumulative benzo (fl)pyrene exposure. The exposure-response trends were stronger when examined across the exposed categories. There was a monotonic but not statistically significant trend between cumulative benzo(fl)pyrene exposure and stomach cancer. Bladder cancer was not associated with benzo(fl)pyrene or benzene exposure. No other cancers or deaths were associated with these exposures. 

Table 1 Mortality from cancer of the stomach and other causes between 1 January 1946 and 28 February 1981 among 1327 male workers in a factory making ammonium nitrate fertilizer. Deaths observed compared with deaths expected from statistics for workers in comparable jobs in the locality. Statistics for heavily and less heavily exposed workers combined ...

The eombined ineidence of stomach, liver, prostate, and lymphohematopoeitic cancers was increased among 2,050 male and 1,924 female Finnish workers occupationally exposed primarily to trichloroethylene (Antilla et al. 1995). The workers were exposed principally through inhalation, although there was some dermal contact. The statistical power of this study was low. 

Asbestos has been shown to cause cancer of the lung and stomach according to studies of workers and others exposed to asbestos. There is no level of exposure to asbestos fibers that... 

In the Montreal case-control study carried out by Siemiatycki (1991) (see monograph on dichloromethane in this volume), the investigators estimated the associations between 293 workplace substances and several types of cancer. Isocyanates were one of the substances, and it was stated that the most common form in this study was toluene diisocyanates. The main occupations to which isocyanate exposure was attributed in this study were motor vehicle refinishers, motor vehicle mechanics and foundry workers. Only 0.8% of the study subjects had ever been exposed to isocyanates. For most types of cancer examined (oesophagus, stomach, colon, rectum, pancreas, prostate, bladder, kidney, skin melanoma, lymphoma), there was no indication of an excess risk due to isocyanates. For lung cancer, in the population subgroup of French Canadians (the majority ethnic group in this region), based on 10 cases exposed at any level, the odds ratio was 2.2 (90% CI, 0.9-5.3). [The interpretation of the null results has to take into account the small numbers and presumably low exposure levels. Workers had multiple exposures.]... 

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