How Does Radon Induce Lung Cancer?
Radon decays into a series of solid radioactive products that can be inhaled and then deposited onto the pulmonary epithelium. Two of the alpha-emitting decay products, polonium-214 and polonium-218, deliver the majority of the radiogenic dose to the lungs and have been identified as the primary cause of radon-induced lung cancer.2-5 These decay products cause single- and double-strand DNA breaks as well as indirect genotoxic and nongenotoxic effects on cells, which can lead to malignancy.2,4,5
Does Radon Present a Substantial Risk to Individuals Who Have Never Smoked?
In the United States, up to 20% of lung cancer deaths each year occur in individuals who have never smoked, which translates to about 30,000 Americans in 2017.10 Protracted radon exposure is considered the leading cause of lung cancer in this population.1-5
Is a History of High Radon Exposure An Eligible Criterion for Low-Dose CT Screening?
The U.S. Preventive Services Task Force states that the benefit of low-dose computed tomography (CT) screening varies because individuals who are at higher risk of developing lung cancer because of smoking history and other risk factors, such as high radon exposure, are more likely to benefit than individuals who have no risk factors.11 Furthermore, the National Comprehensive Cancer Network guidelines recommend low-dose CT screening beginning at 50 years of age for individuals with at least a 20 pack-year smoking history and documented high radon exposure.12 Interviews to assess eligibility for low-dose CT screening present an opportunity to educate patients about the risks posed by smoking and radon exposure, even if the individual is not eligible for low-dose CT screening. It is important to note that the American Academy of Family Physicians concludes that the evidence is insufficient to recommend for or against screening for lung cancer with low-dose CT in persons at high risk based on age and smoking history.13
Address correspondence to R. William Field, PhD, MS, at
bill-field@ uiowa.edu. Reprints are not available from the author.
Author disclosure: No relevant financial affiliations.
References
1. Field RW, Withers BL. Occupational and environmental causes of lung cancer. Clin Chest Med. 2012; 33(4): 681-703.
2. Conference of Radiation Control Program Directors. Reducing the risk from radon: information and interventions. A guide for health care providers. http://www.radonleaders.org/sites/default/files/Health CareProfessionalsGuide_Radon_2018_FINAL_CRCPD%20E-18-2.pdf. Accessed June 27, 2018.
World Health Organization. WHO handbook on indoor radon: a public health perspective. http:// apps.who.int/iris/bitstream/10665/ 44149/1/9789241547673_eng.pdf. Accessed June 28, 2018. 6. Lubin JH, Wang ZY, Boice JD Jr., et al. Risk of lung cancer and residential radon in China: pooled results of two studies. Int J Cancer. 2004; 109(1): 132-137. 7. Darby S, Hill D, Auvinen A, et al. Radon in homes and risk of lung cancer:
collaborative analysis of individual data from 13 European case-control studies. BMJ. 2005; 330(7485): 223. 8. Krewski D, Lubin JH, Zielinski JM, et al. Residential radon and risk of lung cancer: a combined analysis of 7 North American case-control studies. Epidemiology. 2005; 16(2): 137-145. 9. U.S. Environmental Protection Agency. EPA assessment of risks from radon in homes. https:// www.epa.gov/sites/production/files/2015-05/ documents/402-r-03-003.pdf. Accessed June 28, 2018.
10. Simon S. Lung cancer risks for non-smokers. November 6, 2017. American Cancer Society. https:// www.cancer.org/latest-news/why-lungcancer-strikes-nonsmokers.html. Accessed June 28, 2018.
11. Moyer VA. Screening for lung cancer: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2014; 160(5): 330-338.
12.
National Comprehensive Cancer Network. NCCN quick guide:
lung cancer screening. https:// www.nccn.org/patients/guidelines/ quick_guides/lung_screening/files/assets/basic-html/page-1.html#. Accessed June 28, 2018.
13. American Academy of Family Physicians. Clinical preventive service recommendation: lung cancer. https:// www.aafp.org/patient-care/ clinical-recommendations/all/lung-cancer.html. Accessed June 28, 2018.
leading cauSe of LUNG cancer
AMONG NON-SMOKERS
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