CT lung screening useful for some smokers, but drawbacks remain
Annual lung cancer screening with low-dose computed tomography (LDCT) may benefit some current and former smokers, but uncertainty exists regarding the potential harms of screening, according to a recent review. The review, a collaborative initiative of the American Cancer Society, the American Society of Clinical Oncology, the National Comprehensive Cancer Network, and the American College of Chest Physicians, yielded the following two recommendations:
- For smokers and former smokers aged 55 to 74 years who have smoked for 30 pack-years or more and either continue to smoke or have quit within the past 15 years, clinicians should offer annual lung cancer screening with LDCT rather than annual screening with chest radiograph or no screening, but only in settings that can deliver the comprehensive care provided to National Lung Screening Trial participants.
- CT screening should not be performed in individuals who have accumulated fewer than 30 pack-years of smoking or are either younger than 55 years or older than 74 years; in individuals who quit smoking more than 15 years ago; or in individuals with severe comorbidities that would preclude potentially curative treatment, limit life expectancy, or both.
Peter B. Bach, MD, of the Memorial Sloan-Kettering Cancer Center, New York, New York, and colleagues conducted the systematic review to examine the evidence regarding the benefits and harms of LDCT screening for lung cancer. As they reported in JAMA, eight randomized trials and 13 cohort studies involving a total of 53,454 participants in LDCT screening met criteria for inclusion.
Across all trials and cohorts, approximately 20% of individuals in each round of screening had positive results requiring some degree of follow-up, and approximately 1% had lung cancer. However, the authors of the review noted that although LDCT screening identified a relatively high percentage of subjects with nodules, the vast majority of those nodules were benign. Additional imaging triggered by those nodules increases the patient's radiation exposure, and the surgical procedures performed for benign disease can lead to major and sometimes fatal complications, although the rates of those occurrences were low.
Patients might also experience fear and anxiety at even the slightest suspicion of lung cancer, perhaps even leading people to resume or increase their smoking habit, so scan interpretations need to be worded carefully and patients need to be properly educated regarding the meaning of the results.
Although LDCT screening for lung cancer can benefit persons at increased risk for the disease, the investigators cautioned that such testing is not a substitute for smoking cessation, and that not smoking is the most important way to prevent lung cancer. They also noted that the most effective duration or frequency of screening is not known.