Radiation Risks Potentially Associated with Low-Dose CT Screening of Adult Smokers for Lung Cancer

PURPOSE: To estimate the radiation-related lung cancer risks associated with annual low-dose computed tomographic (CT) lung screening in adult smokers and former smokers, and to establish a baseline risk that the potential benefits of such screening should exceed.

MATERIALS AND METHODS: The estimated lung radiation dose from low-dose CT lung examinations corresponds to a dose range for which there is direct evidence of increased cancer risk in atomic bomb survivors. Estimated dose-, sex-, and smoking status–dependent excess relative risks of lung cancer were derived from cancer incidence data for atomic bomb survivors and used to calculate the excess lung cancer risks associated with a single CT lung examination at a given age in a U.S. population. From these, the overall radiation risks associated with annual CT lung screening were estimated.

RESULTS: A 50-year-old female smoker who undergoes annual CT lung screening until age 75 would incur an estimated radiation-related lung cancer risk of 0.85%, in addition to her otherwise expected lung cancer risk of approximately 17%. The radiation-associated cancer risk to other organs would be far lower. If 50% of all current and former smokers in the U.S. population aged 50–75 years received annual CT screening, the estimated number of lung cancers associated with radiation from screening would be approximately 36,000, a 1.8% (95% credibility interval: 0.5%, 5.5%) increase over the otherwise expected number.

CONCLUSION: Given the estimated upper limit of a 5.5% increase in lung cancer risk attributable to annual CT-related radiation exposure, a mortality benefit of considerably more than 5% may be necessary to outweigh the potential radiation risks.

© RSNA, 2004


  • 1 Henschke CI, McCauley DI, Yankelevitz DF, et al. Early lung cancer action project: overall design and findings from baseline screening. Lancet 1999; 354:99-105. Crossref, MedlineGoogle Scholar
  • 2 Sone S, Li F, Yang ZG, et al. Results of 3-year mass screening programme for lung cancer using mobile low-dose spiral computed tomography scanner. Br J Cancer 2001; 84:25-32. Crossref, MedlineGoogle Scholar
  • 3 Nawa T, Nakagawa T, Kusano S, Kawasaki Y, Sugawara Y, Nakata H. Lung cancer screening using low-dose spiral CT: results of baseline and 1-year follow-up studies. Chest 2002; 122:15-20. Crossref, MedlineGoogle Scholar
  • 4 Garg K, Keith RL, Byers T, et al. Randomized controlled trial with low-dose spiral CT for lung cancer screening: feasibility study and preliminary results. Radiology 2002; 225:506-510. LinkGoogle Scholar
  • 5 Sobue T, Moriyama N, Kaneko M, et al. Screening for lung cancer with low-dose helical computed tomography: anti-lung cancer association project. J Clin Oncol 2002; 20:911-920. Crossref, MedlineGoogle Scholar
  • 6 Swensen SJ, Jett JR, Hartman TE, et al. Lung cancer screening with CT: Mayo Clinic experience. Radiology 2003; 226:756-761. LinkGoogle Scholar
  • 7 Pastorino U, Bellomi M, Landoni C, et al. Early lung-cancer detection with spiral CT and positron emission tomography in heavy smokers: 2-year results. Lancet 2003; 362:593-597. Crossref, MedlineGoogle Scholar
  • 8 Vastag B. Lung screening study to test popular CT scans. JAMA 2002; 288:1705-1706. Crossref, MedlineGoogle Scholar
  • 9 Hillman BJ. Economic, legal, and ethical rationales for the ACRIN national lung screening trial of CT screening for lung cancer. Acad Radiol 2003; 10:349-350. Crossref, MedlineGoogle Scholar
  • 10 Aberle DR, Gamsu G, Henschke CI, Naidich DP, Swensen SJ. A consensus statement of the Society of Thoracic Radiology: screening for lung cancer with helical computed tomography. J Thorac Imaging 2001; 16:65-68. Crossref, MedlineGoogle Scholar
  • 11 Miettinen OS, Henschke CI. CT screening for lung cancer: coping with nihilistic recommendations. Radiology 2001; 221:592-596. LinkGoogle Scholar
  • 12 Patz EF, Jr, Black WC, Goodman PC. CT screening for lung cancer: not ready for routine practice. Radiology 2001; 221:587-591. LinkGoogle Scholar
  • 13 Bach PB, Niewoehner DE, Black WC. Screening for lung cancer: the guidelines. Chest 2003; 123(suppl 1):83S-88S. Crossref, MedlineGoogle Scholar
  • 14 Mahadevia PJ, Fleisher LA, Frick KD, Eng J, Goodman SN, Powe NR. Lung cancer screening with helical computed tomography in older adult smokers: a decision and cost-effectiveness analysis. JAMA 2003; 289:313-322. Crossref, MedlineGoogle Scholar
  • 15 Thompson DE, Mabuchi K, Ron E, et al. Cancer incidence in atomic bomb survivors. Part II. Solid tumors, 1958–1987. Radiat Res 1994; 137(suppl 2):S17-S67. Google Scholar
  • 16 National Research Council. Committee on the Biological Effects of Ionizing Radiations Health effects of exposure to low levels of ionizing radiation: BEIR V. Washington, DC: National Academy Press, 1990. Google Scholar
  • 17 Gilbert ES, Stovall M, Gospodarowicz M, et al. Lung cancer after treatment for Hodgkin’s disease: focus on radiation effects. Radiat Res 2003; 159:161-173. Crossref, MedlineGoogle Scholar
  • 18 Tokarskaya ZB, Scott BR, Zhuntova GV, et al. Interaction of radiation and smoking in lung cancer induction among workers at the Mayak nuclear enterprise. Health Phys 2002; 83:833-846. Crossref, MedlineGoogle Scholar
  • 19 Melloni B, Vergnenegre A, Lagrange P, Bonnaud F. Radon and domestic exposure. Rev Mal Respir 2000; 17:1061-1071. MedlineGoogle Scholar
  • 20 Morrison HI, Villeneuve PJ, Lubin JH, Schaubel DE. Radon-progeny exposure and lung cancer risk in a cohort of Newfoundland fluorspar miners. Radiat Res 1998; 150:58-65. Crossref, MedlineGoogle Scholar
  • 21 Neugut AI, Murray T, Santos J, et al. Increased risk of lung cancer after breast cancer radiation therapy in cigarette smokers. Cancer 1994; 73:1615-1620. Crossref, MedlineGoogle Scholar
  • 22 Ford MB, Sigurdson AJ, Petrulis ES, et al. Effect of smoking and radiotherapy on lung carcinoma in breast cancer survivors. Cancer 2003; 98:1457-1464. Crossref, MedlineGoogle Scholar
  • 23 Pershagen G, Akerblom G, Axelson O, et al. Residential radon exposure and lung cancer in Sweden. N Engl J Med 1994; 330:159-164. Crossref, MedlineGoogle Scholar
  • 24 Samet JM, Pathak DR, Morgan MV, Key CR, Valdivia AA, Lubin JH. Lung cancer mortality and exposure to radon progeny in a cohort of New Mexico underground uranium miners. Health Phys 1991; 61:745-752. Crossref, MedlineGoogle Scholar
  • 25 Hornung RW, Deddens J, Roscoe R. Modifiers of exposure-response estimates for lung cancer among miners exposed to radon progeny. Environ Health Perspect 1995; 103(suppl 2):49-53. CrossrefGoogle Scholar
  • 26 Pierce DA, Sharp GB, Mabuchi K. Joint effects of radiation and smoking on lung cancer risk among atomic bomb survivors. Radiat Res 2003; 159:511-520. Crossref, MedlineGoogle Scholar
  • 27 Pierce DA, Preston DL. Radiation-related cancer risks at low doses among atomic bomb survivors. Radiat Res 2000; 154:178-186. Crossref, MedlineGoogle Scholar
  • 28 National Council on Radiation Protection and Measurements. Uncertainties in fatal cancer risk estimates used in radiation protection Report 126. Bethesda, Md: National Council on Radiation Protection and Measurements, 1997. Google Scholar
  • 29 National Cancer Institute. Report of the NCI-CDC working group to revise the 1985 NIH radioepidemiological tables Report NIH 03–5387. Bethesda, Md: National Cancer Institute, 2003. Google Scholar
  • 30 Merrill RM. Measuring the projected public health impact of lung cancer through lifetime and age-conditional risk estimates. Ann Epidemiol 2000; 10:88-96. Crossref, MedlineGoogle Scholar
  • 31 Villeneuve PJ, Mao Y. Lifetime probability of developing lung cancer, by smoking status, Canada. Can J Public Health 1994; 85:385-388. MedlineGoogle Scholar
  • 32 Arias E. United States life tables, 2000. Natl Vital Stat Rep 2002; 51:1-38. MedlineGoogle Scholar
  • 33 Lew EA, Garfinkel L. Differences in mortality and longevity by sex, smoking habits, and health status. Transactions–Society of Actuaries 1987; 39:107-126. Google Scholar
  • 34 Land CE, Sinclair WK. The relative contributions of different organ sites to the total cancer mortality associated with low-dose radiation exposure. Ann ICRP 1991; 22:31-57. Crossref, MedlineGoogle Scholar
  • 35 United Nations Scientific Committee on the Effects of Atomic Radiation. Sources and effects of ionizing radiation: UNSCEAR 2000 report to the General Assembly, with scientific annexes New York, NY: United Nations, 2000. Google Scholar
  • 36 International Commission on Radiological Protection. 1990 recommendations of the International Commission on Radiological Protection Oxford, England: Pergamon, 1991. Google Scholar
  • 37 Henschke CI, Yankelevitz DF, Libby D, Kimmel M. CT screening for lung cancer: the first ten years. Cancer J 2002; 8(suppl 1):S47-S54. Crossref, MedlineGoogle Scholar
  • 38 From the Centers for Disease Control and Prevention. Prevalence of current cigarette smoking among adults and changes in prevalence of current and some day smoking: United States, 1996–2001. JAMA 2003; 289:2355-2356. Crossref, MedlineGoogle Scholar
  • 39 Nishizawa K, Iwai K, Matsumoto T, et al. Estimation of the exposure and a risk-benefit analysis for a CT system designed for a lung cancer mass screening unit. Radiat Prot Dosimetry 1996; 67:101-108. CrossrefGoogle Scholar
  • 40 Jones DG, Shrimpton PC. Survey of CT practice in the UK: normalised organ doses for x-ray computed tomography calculated using Monte Carlo techniques Harwell, England: National Radiological Protection Board, 1991. Google Scholar
  • 41 Maurer WJ. Breast cancer screening complacency and compliance. Wis Med J 1995; 94:305-306. MedlineGoogle Scholar
  • 42 Kruger RL, Schueler BA. A survey of clinical factors and patient dose in mammography. Med Phys 2001; 28:1449-1454. Crossref, MedlineGoogle Scholar
  • 43 Young KC, Burch A. Radiation doses received in the UK Breast Screening Programme in 1997 and 1998. Br J Radiol 2000; 73:278-287. Crossref, MedlineGoogle Scholar
  • 44 Brenner DJ, Sawant SG, Hande MP, et al. Routine screening mammography: how important is the radiation-risk side of the benefit-risk equation? Int J Radiat Biol 2002; 78:1065-1067. Crossref, MedlineGoogle Scholar
  • 45 Law J, Faulkner K. Concerning the relationship between benefit and radiation risk, and cancers detected and induced, in a breast screening programme. Br J Radiol 2002; 75:678-684. Crossref, MedlineGoogle Scholar
  • 46 Merrill RM, Henson DE, Barnes M. Conditional survival among patients with carcinoma of the lung. Chest 1999; 116:697-703. Crossref, MedlineGoogle Scholar

Article History

Published in print: May 2004