Does screening reduce lung cancer mortality?
However, a cohort study using annual CT scanning to screen 3246 patients for lung cancer came to a different conclusion.3 The authors compared the observed number of lung cancer cases, resections, advanced lung cancer diagnoses, and deaths in screened patients with the expected rates based on validated prediction models. Lung cancer was diagnosed in 144 patients compared with 44 expected cases (RR=3.2; 95% CI, 2.7–3.8). Subsequently, 109 patients underwent lung resection compared with 11 expected (RR=10.0; 95% CI, 8.2–11.9). However, there was no decline in advanced cancers (42 actual vs 33 expected; P=.14) and no difference in deaths due to lung cancer (38 actual vs 38.8 expected; P=.9). The 81 patients diagnosed in this study with stage I disease who underwent surgical resection had 4-year estimated survival rates of 94% (95% CI, 85%–97%), matching the prior low-dose CT study.
Major studies of both methods are ongoing
Other major studies are in progress. There is an RCT involving 154,942 male and female patients using annual chest x-ray screening vs no screening that will involve 14 years of follow-up.4 Another RCT is evaluating annual low-dose CT vs annual chest x-ray for 3 years in 50,000 at-risk men and women.5 Finally, investigators are conducting an RCT with 4000 at-risk patients comparing annual CT screening with no screening.6
Recommendations from others
The US Preventive Services Task Force gives an “I” recommendation (data insufficient) to screening for lung cancer with cytology, chest x-ray, or CT scanning.7 The American College of Chest Physicians stated in 2003 that the early studies of low-dose CT appeared promising; however, they recommended that individuals should only be screened with low-dose CT in the context of well- designed clinical trials.8
