Overdiagnosis. Routine LDCT will likely result in some degree of overdiagnosis—eg, detection of low-grade cancers that would either regress on their own or simply not progress—and overtreatment, with the potential for complications.
Full impact is unknown
The ultimate balance of benefits and harms of the USPSTF’s lung cancer screening draft recommendation rests on some unknowns. Widespread screening is unlikely to achieve the same results as did the NLST. As already noted, those enrolled in the NLST were relatively young and had large pack-year smoking histories. The Task Force acknowledges that the 20% reduction in lung cancer mortality achieved in the NLST is unlikely to be duplicated in older patients and individuals with less significant smoking histories. Additional harms will likely accrue if suspicious findings are more aggressively pursued than they were in this study. The potential harms, as well as benefits, from incidental findings on chest LDCT scans are also unknown.
The number of screenings. The potential for benefits beyond 3 screenings is also unknown, as the USPSTF’s projections in such cases are based on modeling. The degree of overdiagnosis is not fully understood, nor is the harm that could result from the accumulated radiation of what could be an annual LDCT for 25 years. The harm/benefit ratio will become clearer with time and can then be compared with other medical interventions.
Financial burden. While it may appear to some that the draft recommendation would unfairly benefit smokers by allowing them to undergo free annual CT screening, patients are likely to incur significant financial obligations as a result of doing so. The Affordable Care Act mandates that the annual LDCT screening would have to be offered with no patient cost sharing, but follow-up CTs for questionable findings, biopsies, and treatment will all be subject to deductibles and copayments.
Recommendations of others
Other organizations have adopted recommendations on lung cancer screening similar to the USPSTF proposal. These include the American Association for Thoracic Surgery, American Cancer Society, American College of Chest Physicians, American Lung Association, American Society of Clinical Oncology, and American Thoracic Society. Most apply to those ages 55 to 74 years and use other inclusion criteria of the NLST. Some stipulate that patients should be in good enough health to benefit from early detection, and most include a reference to the quality of the centers at which screening should occur. The American Academy of Family Physicians is currently considering what its recommendation on lung cancer screening will be.
Final USPSTF recommendation expected soon
Noticeably absent from the news coverage of the proposed USPSTF recommendation was the word “draft.” The Task Force has now collected public comments about its proposed recommendation and will be considering potential changes to the wording. Publication of the final recommendation is expected in December—shortly after press time.