Lung Cancer Screening Practices of Primary Care Physicians

Results From a National Survey

Carrie N. Klabunde, PhD; Pamela M. Marcus, PhD; Paul K. J. Han, MD, MA, MPH; Thomas B. Richards, MD; Sally W. Vernon, PhD; Gigi Yuan, MS; Gerard A. Silvestri, MD, MS


Ann Fam Med. 2012;10(2):102-110. 

In This Article


To our knowledge, this is the first national study of primary care physicians' lung cancer screening practices to consider sputum cytology and LDCT—the new modality assessed in the recent NLST—in addition to chest radiograph. Four prior national surveys have evaluated primary care physicians' use of or recommendations for chest radiograph;[15,16,21,22] however, those surveys took place more than 2 decades ago and did not include all 3 primary modalities that have been considered for lung cancer early detection.

Our findings that a majority of primary care physicians reported ordering lung cancer screening tests for asymptomatic patients and that patients have recently asked them about lung cancer screening suggest that ordering of these tests is common among these physicians, as are patient-physician discussions about lung cancer screening, even though at the time of the survey, lung cancer screening was not recommended by major expert groups in the United States. Although direct comparison of our estimates with those of earlier studies[16,17,22,23] is not possible because of differences in study designs, it appears that US primary care physicians have not decreased their practice of ordering chest radiographs to screen asymptomatic patients for lung cancer.

Primary care physicians' ordering of unproven lung cancer screening technologies has several implications. There is potential for psychological harm from false-positive or false-negative test results, and physical harm from invasive procedures performed to follow up false-positive screening tests. Results from the NLST's feasibility phase, the Lung Screening Study, indicated that the issue of false-positive results is nontrivial: the percentage of screened participants with a false-positive examination was higher for LDCT than for chest radiograph, and LDCT showed a false-positive rate on an initial screen of 21% and on a second screen of 33%.[34] Imaging tests can also contribute to overdiagnosis of lung cancer and other conditions,[35] and to radiation-induced cancers, especially with repeated LDCT examinations and the diagnostic imaging that often follows positive examinations.[36,37] Finally, use of unproven lung cancer screening technologies ultimately drives up health care costs.[37]

To better understand reasons for primary care physicians' apparent overuse of lung cancer screening, we examined the potential influence of physician and practice setting characteristics, physician beliefs and practice style, and patient demand on physicians' lung cancer screening test ordering. We found in multivariate modeling that physicians who believe expert groups recommend lung cancer screening or that screening tests are effective in reducing lung cancer mortality, said they would recommend lung cancer screening for asymptomatic patients, or reported that their patients had asked them about being screened for lung cancer were significantly more likely to have ordered chest radiographs or LDCT as lung cancer screening tests in the past year. Physicians who graduated from medical school 20 years ago or more were significantly more likely to have ordered LDCT. Our findings that physician beliefs about screening and older physician age are associated with ordering lung cancer screening tests are consistent with previous studies of chest radiograph ordering.[18,22,23] The finding that patient demand is associated with physicians' reports of lung cancer screening test ordering parallels earlier work showing that patient requests influence physicians' ordering of genetic tests for cancer susceptibility.[32] Our assessment of physician characteristics associated with the ordering of lung cancer screening tests may aid efforts to target educational interventions to physicians most in need of updated information about lung cancer screening's evidence base and guidelines.

Strengths of this study include its large, nationally representative sample of practicing primary care physicians and high survey response rate. Our study also has some limitations. Physicians' self-reports of their lung cancer screening recommendations and practices were not validated with other data sources such as medical records or claims. To minimize respondent burden, the survey module on lung cancer screening was relatively brief, and we were not able to ask more detailed questions about specific characteristics of patients for whom physicians ordered lung cancer screening tests, such as type and extent of smoking exposure. We also did not ask whether the physician's practice had chest radiography available on site, which may influence chest radiograph ordering. Lastly, we did not ask to what extent physicians may be initiating discussions about lung cancer screening with their patients. All of these are key areas for future research on physicians' lung cancer screening recommendations and practices.

The disconnect between lung cancer screening evidence and practice that our study documents provides important context for considering the potential consequences of the recent, highly publicized NLST findings.[38] Those findings are specific to individuals aged 50 to 75 years who were current or former smokers with at least a 30–pack-year history of smoking. Any change in screening recommendations that might occur as a result of the NLST would apply only to this select, high-risk population and 1 specific technology (ie, LDCT). Our results showing gaps in primary care physicians' knowledge of lung cancer screening and use of unproven screening modalities suggest that in the United States—where most cancer screening occurs opportunistically rather than through organized programs—a substantial proportion of the adult population could be inappropriately screened unless there are concerted efforts to inform primary care physicians of appropriate interpretation of NLST findings and how best to apply them in practice.

Finally, 3 additional factors heighten the need for educating primary care physicians and patients about lung cancer screening's evidence base, guidelines, potential harms, and costs. First, anecdotal evidence suggests that announcement of NLST results may have prompted some medical professionals to more widely promote lung cancer screening and their LDCT facilities;[37] second, the US general public has an overly positive view of cancer screening and limited understanding of its potential harms;[39] and third, use of computed tomography scans in general is rising rapidly in the United States.[40] These factors along with our study's results and the evolving evidence base underscore the importance of continued monitoring of primary care physicians' knowledge, beliefs, and practices related to lung cancer screening.