When low-dose computed tomography (LDCT) was used in second and subsequent lung cancer screens, the rate of repeating early repeat scans for suspicious findings decreased by more than 80%. These findings, from the German Lung Cancer Screening Intervention Trial (LUSI), emphasize the need to have an organized screening program with the baseline scan available for comparison.
In the United States, the National Lung Cancer Screening Trial (NLST) showed that annual lung cancer screening of high-risk persons with LDCT reduces lung cancer mortality by 20% and overall mortality by 7%.
Multiple lung cancer screening trials are now ongoing throughout the world, but one concern is the high number of early repeat scans for suspicious findings that are in fact not lung cancer. This high number of false positives could make screening impractical due to cost, invasive follow-up procedures, and anxiety for the patients.
The LUSI is comparing no intervention (n = 2,023) to five annual screens of persons ages 50 to 69 years with a history of heavy tobacco smoking (n = 2,029). All the participants have been followed for at least 3 years, but many have been followed for 5 years.
The control arm is tracked with an annual questionnaire and query of cancer registries. The LUSI is ongoing but the current analyses compare the first screening round to subsequent rounds with regard to performance indicators, such as early recall rate, detection rate, and interval cancer rate.
The results, published in the Journal of Thoracic Oncology (2015; doi:10.1097/JTO.0000000000000530), showed a strong decline in the early recall rate from 20% in the first screening round to 3% to 4% in rounds 2 to 4 (P < .0001). The detection of lung cancer was 1.1% in the first round but then declined to 0.5%, on average, for the subsequent rounds.
The cumulative number of advanced lung cancers was almost identical between the control and intervention groups for the first 2 years, but by year 3 the number of advanced cancers in the screening group began to decline. The same trend was observed for the overall mortality.
The authors concluded, “Our data indicate that the most prominent side effect, false positive alarm, cannot be controlled if the choice of doctor is at the screenee’s discretion at every annual screening visit. The early recall rates of rounds 2 to 4 would have been [approximately] 30%, instead of 3% to 4%, if the prior scans were not available. Thus, a potential lung cancer screening program must be organized such that all previous images and results are