Screening for Lung Cancer

Summary

A Cochrane review [Abstract]1 included 11 studies (conducted in Europe and the USA) with a total of 94 445 subjects aged 40 years or older. Most studies included subjects with HASH(0x2fdd378) 20 pack-year smoking history. Low-dose computed tomography (LDCT) screening was compared to no screening in 7 studies and to chest radiography (CXR) screening in 4 studies. Screening frequency included annual, biennial and incrementing intervals, and the duration of screening ranged from 1 year to 10 years. Mortality follow-up was from 5 to approximately 12 years.

LDCT screening reduced lung-cancer mortality (RR 0.79, 95% CI 0.72 to 0.87; 8 studies, n=91 122) and all-cause mortality (RR 0.95, 95% CI 0.91 to 0.99; 8 studies, n=91 107) compared to no screening or CXR screening. Invasive tests occurred more frequently in the LDCT group (RR 2.60, 95% CI 2.41 to 2.80; 3 studies, n=60 003). False-positive results and recall rates were higher with LDCT screening compared to screening with CXR. Estimated overdiagnosis with LDCT screening was 18% (95% CI 0 to 36%; RD 0.18, 95% CI -0.00 to 0.36; 5 studies, n=28 656).Four studies compared different aspects of health-related quality of life (HRQoL). Participants in LDCT screening reported lower anxiety scores than in the control group (SMD -0.43, 95% CI -0.59 to -0.27; 3 studies, n=8 153).

A Cochrane review [Abstract]2 included 9 studies (8 RCTs, one controlled trial) with a total of 453 965 subjects. In one large study (77 470 participants in the control group, 77 464 in the intervention group, both men and women between the ages of 55 and 74 years, including both smokers and non-smokers) comparing annual chest x-ray screening with usual care there was no reduction in lung cancer mortality (RR 0.99, 95% CI 0.91 to 1.07).

In a meta-analysis of studies comparing different frequencies of chest x-ray screening, frequent screening with chest x-rays was associated with an 11% relative increase in mortality from lung cancer compared with less frequent screening (RR 1.11, 95% CI 1.00 to 1.23). However several of the trials included in this meta-analysis had potential methodological weaknesses. A non statistically significant trend was observed to reduced mortality from lung cancer when screening with chest x-ray and sputum cytology was compared with chest x-ray alone (RR 0.88, 95% CI 0.74 to 1.03). In one large methodologically rigorous trial in high-risk smokers and ex-smokers (aged 55 to 74 years, with HASH(0x2fdd378) 30 pack-years of smoking or having quitted HASH(0x2fdd780) 15 years prior to entry if ex-smokers; 26 722 subjects assigned to annual screening with low-dose CT, 26 732 subjects to annual screening with chest radiography), the relative risk of death from lung cancer was significantly reduced in the low-dose CT group (RR 0.80, 95% CI 0.70 to 0.92).