Asymptomatic Smoker Who Requests Lung Cancer Screening

A 57-year-old man requests an extensive medical evaluation as part of a transition in the ownership of his business. He is generally healthy, although he reports that his capacity for physical exertion has diminished over the past several years. He denies chest pain with effort, dyspnea at night or on exertion, cough, and sputum production.

HISTORY
The patient has essential hypertension, which is reasonably well controlled with a ß-blocker and a diuretic. Several years earlier, hypercholesterolemia was diagnosed; since then, he has taken a statin with good results. He has a 30 pack-year smoking history. He runs a large family business that often requires long hours and significant travel.

PHYSICAL EXAMINATION
Vital signs are normal, as are results of examination of the head, ears, eyes, nose, and throat. There are no enlarged lymph nodes. Auscultation of the lungs reveals a somewhat prolonged expiratory phase but no rales or wheezes. Heart is normal, without murmurs, heaves, or gallops. Abdomen is normal. There is no edema.

LABORATORY AND IMAGING RESULTS
Results of a hemogram and chemistry panel are normal. ECG reveals mild left ventricular hypertrophy. Chest radiograph is normal.

SCREENING STUDIES
Results of a screening colonoscopy are normal. A prostate-specific antigen determination, requested by the patient, shows a level of 1.0 ng/mL.

Because he is a smoker, he asks about screening for lung cancer.

Which of the following would be the most appropriate response to this man?

A. Screening with CT scanning and sputum cytology is indicated in smokers and should be initiated now.
B. Screening for lung cancer has shown no beneficial effects in any studies performed to date.
C. Smoking cessation will do more to reduce his mortality risk than CT screening.
D. Whether to screen is the patient's decision; those who opt for screening incur essentially no associated risks.

Answer on next page

CORRECT ANSWER: C
Not all experts would agree with every aspect of the folowing discussion of lung cancer screening; some advocacy groups view the available data somewhat differently—and make different recommendations as a result. Fortunately, a large National Cancer Institute trial involving 50,000 smokers is under way; data from that study should become available in 2009 and will provide more definitive guidance on the issue of screening.¹

The US Preventive Services Task Force (USPSTF) concluded that "current evidence is insufficient to recommend for or against screening asymptomatic persons for lung cancer with either low-dose computerized tomography, chest x-ray, sputum cytology, or a combination of these tests."¹ In the studies the USPSTF analyzed, lung cancers were detected earlier in patients who underwent various screening tests than in those who had not been screened; however, this advantage did not translate into a mortality benefit.^1,2 Moreover, the significant number of false-positive results, coupled with the relatively invasive sequelae that followed a positive screening result, created a significant potential for collateral harm from screening. Thus, choice A is not correct.

Evidence of benefit for lung cancer screening. Several observational trials^2,3 have suggested reduced mortality with screening, and these trials are cited by a number of groups that favor routine screening. Most recently, the International Early Lung Cancer Action Program (I-ELCAP) investigators⁴ reported in a major study a clear survival benefit for CT screening in a "high-risk" population (ie, persons with a history of smoking or industrial exposure). Of those patients in the study in whom screening detected a suspicious lesion, 85% had curable, early stage I lesions. Moreover, in those patients in whom diagnosis was confirmed by biopsy and who subsequently had the lesion resected, the estimated 10-year survival rate was 92%. In comparison, none of those who had biopsy-confirmed stage I lesions and received no treatment survived 5 years. Thus, choice B is clearly not correct.

Of interest, a second well-done study, reported just several months after that of the I-ELCAP investigators, showed an increase in lung cancer diagnosis and treatment, but no meaningful reduction in lung cancer mortality associated with CT screening.⁵

Risks of screening. Still, lung cancer screening is not without risks. Data from the solitary pulmonary nodule literature can be used to quantitate, to a degree, the potential risks associated with the evaluation of CT abnormalities. In 3% to 12% of patients who were screened, uncalcified nodules were found; up to 20% of these proved to be benign.³ However, if evaluation eventually involves either mediastinal staging or lobectomy, a 3% mortality rate can be expected.^2,6 In addition to physical risk, lung cancer screening often entails significant psychological and monetary costs. Thus, choice D is not correct.

Benefits of smoking cessation. Smoking cessation (choice C) will effect the greatest reduction in this patient's mortality risk. Most of this reduction may not be accounted for by decreased lung cancer risk; a significant risk of lung cancer remains even a decade or more after smoking cessation. However, quitting slows the evolution of chronic obstructive pulmonary disease and its attendant complications and a significant decrease in coronary artery disease risk is seen very shortly after a patient stops smoking. Thus, smoking cessation has greater efficacy with far less attendant risk than does any screening strategy studied to date.

Outcome of this case. After a detailed discussion with the patient, he elected not to pursue aggressive screening. He successfully stopped smoking and is doing well 1 year later.