Exposure to low dose computed tomography for lung cancer screening and risk of cancer: secondary analysis of trial data and risk-benefit analysis

Abstract

Objective To estimate the cumulative radiation exposure and lifetime attributable risk of cancer incidence associated with lung cancer screening using annual low dose computed tomography (CT). Design Secondary analysis of data from a lung cancer screening trial and risk-benefit analysis. Setting 10 year, non-randomised, single centre, low dose CT, lung cancer screening trial (COSMOS study) which took place in Milan, Italy in 2004-15 (enrolment in 2004-05). Secondary analysis took place in 2015-16. Participants High risk asymptomatic smokers aged 50 and older, who were current or former smokers (≥20 pack years), and had no history of cancer in the previous five years. Main outcome measures Cumulative radiation exposure from low dose CT and positron emission tomography (PET) CT scans, calculated by dosimetry software; and lifetime attributable risk of cancer incidence, calculated from the Biological Effects of Ionizing Radiation VII (BEIR VII) report. Results Over 10 years, 5203 participants (3439 men, 1764 women) underwent 42 228 low dose CT and 635 PET CT scans. The median cumulative effective dose at the 10th year of screening was 9.3 mSv for men and 13.0 mSv for women. According to participants’ age and sex, the lifetime attributable risk of lung cancer and major cancers after 10 years of CT screening ranged from 5.5 to 1.4 per 10 000 people screened, and from 8.1 to 2.6 per 10 000 people screened, respectively. In women aged 50-54, the lifetime attributable risk of lung cancer and major cancers was about fourfold and threefold higher than for men aged 65 and older, respectively. The numbers of lung cancer and major cancer cases induced by 10 years of screening in our cohort were 1.5 and 2.4, respectively, which corresponded to an additional risk of induced major cancers of 0.05% (2.4/5203). 259 lung cancers were diagnosed in 10 years of screening; one radiation induced major cancer would be expected for every 108 (259/2.4) lung cancers detected through screening. Conclusion Radiation exposure and cancer risk from low dose CT screening for lung cancer, even if non-negligible, can be considered acceptable in light of the substantial mortality reduction associated with screening.

Lung cancer screening with low dose CT and radiation harm—from prediction models to cancer incidence data

“…In NLST the LDCT screening test involved an approximate dose of 2 mSv, whereas full-chest CT scanning that was the major diagnostic study used to follow up nodules, involved a dose of about 8 mSv (11). However, the average individual effective dose associated with LDCT test and other procedures used for diagnostic-work up in two Italian studies (in which LDCT was used for follow-up of suspicious nodules) was lower and in the range between 0.9 and 1.7 mSv per year (5,6).…”

Whack-a-mole strategy for multifocal ground glass opacities of the lung

“…Management of the persistent GGO should be observation or surgical intervention. Radiation exposure with CT during follow up could be one of the disadvantages of observation (21), and this problem would be emphasized in young patients.…”

Utility of FDG PET/CT for Assessment of Lung Nodules Identified During Low Dose Computed Tomography Screening

“…[13] In other studies, FDG PET/CT was performed in 3.1 to 6.5% of subjects with lung nodules detected on LDCT. [14,15] For LDCT detected nodules, there is limited data on the impact of FDG PET/CT on clinical decisions. [16] Arguably, a routine FDG PET/CT for every lung nodule might add significantly to the cost of care.…”