Physicians often omit harms when discussing lung cancer screening, study finds

Physicians and patients are discussing the initiation of lung cancer screening with low-dose CT, but physicians are not always mentioning potential harms, and rates of overdiagnosis may be higher than previously reported, two studies found.

To assess the quality of shared decision making about lung cancer screening, researchers in one study conducted a qualitative analysis of transcribed clinical encounters between primary care or pulmonary physicians and 14 patients in private community practices. Patients (64.3% female; mean age, 63.9 years) were presumed to be eligible for lung cancer screening, and visits were recorded between April 1, 2014, and March 1, 2018. Eight patients were current smokers.

Two independent observers rated physicians' communication behaviors using the 12-item OPTION (Observing Patient Involvement in Decision Making) scale, which ranges from 0 to 100 points (with higher scores indicating better shared decision making) in addition to time spent discussing screening and evidence of decision aid use. Results were published online on Aug. 13 by JAMA Internal Medicine.

Physicians universally recommended lung cancer screening, and discussion of harms (e.g., false positives, overdiagnosis) was essentially absent. The mean total OPTION score for all the lung cancer screening conversations was 6 out of 100 (range, 0 to 17). None of the encounters met the minimum skill criteria for eight of the 12 shared decision-making behaviors. The mean total length of visits was 13:07 minutes (range, 3:48 to 27:09 minutes), and the mean time spent discussing lung cancer screening was 0:59 minute (range, 0:16 to 2:19 minutes), or 8% of the total visit duration (range, 1% to 18%). There was no evidence that physicians used decision aids or other patient education materials for lung cancer screening.

The main limitations of the study are its small sample size and its qualitative design, the authors noted. “Although the sample is small and these findings are clearly preliminary, they raise concerns that [shared decision making] in practice may be far from what is intended by guidelines,” they wrote.

An accompanying editorial said the results are “clearly a failing grade” for physicians' shared decision-making skills. “Although [the study] analyzed a small sample of conversations, there is no reason to believe that these conversations were atypical,” the editorialist wrote.

In the second study, researchers conducted a post hoc analysis of the Danish Lung Cancer Screening Trial, which randomized 4,104 patients who currently or formerly smoked to no screening or to five annual low-dose CT screenings. Patients were 50 to 70 years of age and were enrolled from Oct. 1, 2004, to March 31, 2006. Researchers used modeling to calculate the rate of overdiagnosis (the ratio between the absolute difference in cumulative incidence of lung cancer and the cumulative incidence of screen-detected cancers) until follow-up ended on April 7, 2015. The results were also published on Aug. 13 by JAMA Internal Medicine as a research letter.

Screened and unscreened patients (55.3% male; mean age, 57.3 years) were comparable at baseline, with high adherence to screening and few overall losses to follow-up. At the end of follow-up, 96 participants were diagnosed with lung cancer in the screened group (64 cancer cases were detected by screening), compared to 53 participants in the control group. Researchers estimated that overdiagnosis occurred in 67.2% (95% CI, 37.1% to 95.4%) of the cancer cases detected by screening CT, compared to the trial's original estimate of 18.5% (95% CI, 5.4% to 30.6%). Off-protocol screening in the control group was low (7.4% during the trial period and 20.3% during follow-up).

The main limitation of the study is the potential for a higher baseline risk of lung cancer in the trial's screened group, which had a 3.1-percentage point higher rate of patients who smoked heavily than the control group, the authors noted.

“Patients can make informed choices about [low-dose] CT only if practitioners fully disclose all the potential harms of screening, including the risk of overdiagnosis,” an accompanying commentary said. “It will be important for researchers to continue to refine estimates of lung cancer overdiagnosis, allowing physicians to provide more accurate information to our patients.”