Relationship of radioactive radon daughters and cigarette smoking in the genesis of lung cancer in uranium miners

Abstract

This article documents the study of 383 cases of lung cancer in uranium miners and presents for the first time the relationship of radioactive radon gas and cigarette smoking. There is evidence that alpha radiation from radon gas at exposure levels above 465 working level months (WLM) is a strong contributor to the development of lung cancer. Cigarette smoking plays the most significant role in causing lung tumor; this is also noticed in nonminers who smoke cigarettes. A synergistic or additive effect of these two carcinogens is strongly suggested. The data indicate that small cell tumors develop in younger nonsmoking miners exposed to radon levels above 465 WLM. Lung cancers develop in smoking miners at lower levels of radon exposure than in nonsmoking miners. Based on an average mining experience of 15 years, there is substantial evidence that the present maximum allowable limit of 0.3 working levels (WL), or 4 working level months (WLM) per year, is safe, representing a margin of safety of approximately 10:1. Furthermore, a comparison of these data with the radon levels in some homes, averaging in the neighborhood of 0.025 WL, would indicate that health risks at these levels are negligible. It is suggested that 20 picocuries/liter, which equals 0.10 WL, be the maximum allowable level in homes.

Role of exposure to radon and silicosis on the cell type of lung carcinoma in German uranium miners

“…In Colorado Plateau miners, SCLC developed preferentially in younger nonsmokers with exposure levels above 465 WLM. 38 A particular strength of the study is its large size of 3414 lung carcinoma cases with a comprehensive collection of tissue samples and comprehensive data on occupational exposure to radon and its decay products. A potential methodological problem of histopathologic subtyping concerns classification bias.…”

Ionizing Radiation Carcinogenesis

“…People chronically exposed over extended period of employment to hig h level s of a irbo rne radon dec ay products such as are found in uranium mines have developed bronchogenic carcinoma at incidence rates that significantly exceeded the expected rates in either smokers or nonsmokers. However, almost all the lung cancer cases in the western U.S. mines occurred in smokers (Saccomanno et al, 1988). The reported excess relative risks of lung cancer as a function of cumulative dose expressed in working level months of exposure are shown in Figure 18.…”

Cancer Risks from Exposure to Radon in Homes

“…These findings agree with the relative excess of small cell undifferentiated lung cancers seen in the studies on uranium miners. Over time, however, the relative frequency of histologic types has become more normal in miners (64)(65)(66).…”

“…The effect of smoking and exposure to radon among miners has been more or less multiplicative in most studies with adequate data available (35,66,76,77). In a few studies there has been a merely additive relationship (25,40,41) and sometimes even less than an additive effect (34,78).…”