Lobe of origin of lung cancer among asbestos-exposed patients with or without diffuse interstitial fibrosis.

lung cancer among workers exposed to lead. Scand J Work Environ Health 1995;21:460-9. Objective Studies on experimental animals suggest that inorganic lead is a carcinogen. The purpose of the study was to examine whether occupational exposure to lead increases the risk of cancer. Methods The study population comprised 20 700 workers who had been biologically monitored for their blood lead (B-Pb) concentrations during 1973-1983. The mortality and cancer incidence rates were followed among the monitored workers and compared with those of the Finnish general population. An internal comparison of the cancer incidence rates was also done between subcohorts formed according to individual B-Pb levels. Questionnaire-based information was also collected on lifetime occupational history and potential confounders, and exposure history was assessed on an individual basis with a nested case-referent design for lung cancer. Results The internal comparison within the cohort showed a 1.4-fold increase in the overall cancer incidence and a 1.8-fold increase in the incidence of lung cancer among those who had ever had a blood lead level of 2 1.0 ~m o l . 1-I. In the case-referent study, an increased odds ratio for lung cancer was found for concomitant exposure to lead and engine exhaust. The odds ratio for squamous-cell carcinoma of the lung was increased even when the blood lead level had been slightly elevated. Bias or confounding did not explain the risks. C O~C~U S~O~S The results suggest that exposure to lead increases the risk of lung cancer. Co-exposure to engine exhaust and lead may be associated with the risk.

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“…For these exposures, the most dominant increase in the risk has been reported for adenocarcinoma (2, 49,50).…”

Section: Discussionmentioning

confidence: 99%

Excess lung cancer among workers exposed to lead

Anttila¹,

Heikkilä²,

Pukkala³

et al. 1995

Scand J Work Environ Health

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“…For example, among the 15,477 histologically proven cases of primary lung cancer among white men in the Surveillance, Epidemiology, and End Results (SEER) Study, 65% of the tumors originated in the upper lobes compared with 35% in the middle or the lower lobes (10). Among asbestos-exposed individuals, some studies have reported an inversion of this ratio, with a higher proportion of tumors occurring in the lower lobes (12)(13)(14)(15)(16)(17)(18)(19)(20). For example, in a study of 108 patients undergoing lobectomy or pneumonectomy for lung cancer, 62% of asbestos-exposed patients had lower-lobe tumors, in contrast to 25% of the nonexposed patients (p Ͻ 0.0001) (19).…”

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confidence: 99%

Association of Cigarette Smoking and Asbestos Exposure with Location and Histology of Lung Cancer

Lee

Wain²,

Kelsey³

et al. 1998

Am J Respir Crit Care Med

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Prior studies have suggested that lung cancers that arise in association with cigarette smoking favor an upper-lobe location while those associated with asbestos exposure favor a lower-lobe location. An excess of adenocarcinomas has also been reported among cases not exposed to cigarette smoke as well as among those exposed to asbestos. However, these studies typically have not adjusted adequately for potential confounders such as the patient's age, sex, race, or family history of cancer. To better examine the effects of cigarette smoking and asbestos exposure on location and histology of lung cancer, we analyzed data from a large case-control study that included 456 patients with stage I or II lung cancer. Patients with upper-lobe tumors tended to have had more exposure to tobacco as assessed by pack-years smoked (54.7 versus 46.2, p = 0.07) and less time since quitting smoking (3.0 versus 5.5 yr, p = 0.05). In contrast to some prior reports, asbestos exposure was also associated with an upper-lobe location of tumor. Among those with upper-lobe tumors, 14.6% had a history of significant asbestos exposure compared with 5.4% of those with lower-lobe tumors (p < 0.01). The relationship between asbestos exposure and upper-lobe location of tumor was also statistically significant whether stratified by smoking or analyzed by multivariable logistic regression modeling. Adenocarcinomas were more likely among those with less exposure to cigarette smoke based on fewer pack-years smoked (41.5 versus 61.8, p = 0.0001) and more time since quitting smoking (5.0 versus 3.0 yr, p = 0.02). The proportion of patients with significant exposure to asbestos was lower among those with adenocarcinomas but was not statistically significant (9.5 versus 15.3%, p = 0.09). In multivariable logistic regression analysis, longer time since smoking exposure remained a significant predictor of adenocarcinomas (p < 0.02), but history of asbestos exposure did not predict tumor histology. Thus, in patients with lung cancer, both cigarette smoking and asbestos exposure histories favor an upper-lobe location of tumor. Longer time since smoking exposure favors adenocarcinomas, but the history of asbestos exposure does not appear to influence the tumor histology.

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“…Such national reference values are important in Finland, as 40% of the asbestos used during the past several decades consisted of anthophyllite (2), a variety of asbestos of only minor importance in other industrialized countries. There is increasing knowledge on the pulmonary fiber concentrations of Finnish lung cancer and mesothelioma patients, but the number of reference cases representing the general population is small (3)(4)(5).…”

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confidence: 99%