You are seeing Mr. Brown today in the primary care clinic. He has a long history of tobacco abuse, and you notice on his intake form that he wishes to discuss lung cancer screening today. Which of the following statements regarding lung cancer screening can you truthfully make to Mr. Brown?
ExplanationRecently, the National Heart, Lung, and Blood Institute found that low-dose chest CT scanning can detect tumors earlier, and CT was recently demonstrated to reduce lung cancer mortality by 20% in individuals who had at least a 30-pack-year history of smoking (option E). This represented somewhat of a paradigm shift in how lung cancer screening was viewed. Historically, lung cancer screening in even high-risk populations had proven largely unsuccessful as many detected cancers were incurable at the time of detection by screening (option B). A screening test is hardly ever a “no-brainer.” In the case of lung cancer screening, several risks need to be discussed with the patient prior to referral for low-dose CT scanning. First, there is the risk of detection of an incurable cancer as discussed above. Second, even low-dose CT scanning exposes the patient to radiation and may increase their risk for subsequent neoplasm. Finally, every screening test carries a risk of a false positive. In the case of lung cancer screening, false-positive results may lead to invasive biopsies and even drastic surgeries such as pneumonectomy (option C). Finally, although the sensitivity and specificity of a test do not depend on the population risk (a patient’s pretest probability), the posttest probability of disease provided by a positive or negative test does strongly depend on the pretest probability (option D). This is the reason why carefully choosing the appropriate risk patient for each screening test is important.
