Primary Care Corner with Geoffrey Modest MD: Another Downside of Lung Cancer CT Screening

By Dr. Geoffrey Modest

There was a small but I think important study on the perceptions of patients who smoke and had low-dose lung cancer screening –LDCT (see lung cancer CT and continued smoking jamaintmed 2015 in Dropbox, or doi:10.1001/jamainternmed.2015.3558​). This was a VA study of patients who had in-depth semi-structure qualitative interviews about their health beliefs relating to smoking and lung cancer, done in 2014.  Details:

  • 37 patients (89% male, mean age 62, 62% white/27% black or pacific islander, mean 49 pack-years smoking, mean Fagerstrom score of 4.75 — suggesting moderate nicotine dependence) who participated in the VA pilot study on lung cancer screening in one of 151 VA medical centers were interviewed, most after they got their results. There was a detailed pretest description of the risks and benefits of screening.
  • Results:
    • 18 of the participants had abnormal screening results (9 with nodules <1 cm, 12 with nonpulmonary incidental findings)
    • Despite education on the limited benefit of screening, many participants thought that everyone undergoing screening would benefit
    • Many patients thought that screening would give a more precise estimate of their individual risk of cancer, to see “how much damage was done do their lungs” by smoking
    • Many acknowledged the need to quit smoking, but focused on “catching” cancer early
    • Many patients were reassured that by finding a nodule meant that the screening worked for them (and protected them from getting cancer), that finding a cancer meant that it could be cured and was harmless [in fact, >1/3 of the cancers detected by screening in National Lung Screening Trial were > stage 1]. Several thought they were going to get “bad news”, and the lack of an abnormality on CT led to “a lack of urgency for quitting” smoking. “It is more of a relaxing thing that there is a part of my body that I know is working and looks like it is continuing working fine for the rest of the year at least”.
    • Some participants felt that screening would itself cure cancer, that they would not need chemotherapy (and perhaps avoid these treatments that their relatives had gone through)
    • Some people thought they were the “lucky ones”, citing that they knew of people who lived to be 100 and smoked over 50 years without a problem. Some acknowledged that smoking caused cancer but that “like most smokers it’s not going to be me”

For my general critique of the lung cancer screening guidelines, see , which mostly focuses on the limitations of the National Lung Screening Trial and the related development of pretty aggressive national guidelines, and the potential of radiation-induced cancers. This current small qualitative study, done in veterans, brings up another major issue of screening: patients’ understanding and interpretation of both the screening process and the results. My major concerns from this study are:

  • It is often very difficult for patients (including some of us when we are patients…) to think objectively about cancer. It is scary, both in what it is/can do and in its treatment (it is the “crab” that extends itself relentlessly throughout your body, the emperor of all maladies). Many people are willing to take large risks of screening or treatment to decrease their risks from even not-so-aggressive cancer: “just take everything out”. This inability to sort out risks and benefits objectively and not just focus on the word “cancer” more emotionally, I think, leads to misperceptions in this study that screening protected them from cancer, small nodules are not significant but only need followup, that it was okay to continue smoking since they were one of the lucky ones who would not get cancer.
  • ​Although lung cancer is certainly a risk of smoking, many more patients die of cardiovascular disease related to smoking (the single most important correctable cause of heart disease), and almost as many die from COPD (158K lung cancer deaths/year vs 135K with COPD). The focus on CT scans to pick up lung cancer effectively de-emphasizes and diminishes even more important morbidity/mortality issues and provides a false sense of reassurance.
  • Ultimately, there are also ethical and social issues regarding the approach to serious preventable illnesses. Huge amounts of funding and resources are going into early detection of lung cancer, which had very small absolute benefit (decreased mortality by 62 deaths per 100,000 person-years of screening in NLST), instead of inexpensive (and severely underfunded), community-based prevention programs — see prior blog describing a very impressive, low-cost, community-initiated and community-based program in a poor rural Maine community, which achieved impressive cardiovascular risk factor reduction, including for smoking (​ ). Devoting 1/10 the $$ from lung cancer screening to such initiatives would likely have much more dramatic population benefits.

So, this adds to my concerns about the appropriateness of the LDCT screening. In some circumstances, medicalizing (getting CT scans) a social issue (smoking) can lead to undercutting the real social message (smoking is really bad for you, for a lot of reasons beyond lung cancer). As another example where medicalizing may undercut the important public health message, there was a recent study showing that patients put on statins tend to stop doing the lifestyle changes (diet, exercise, weight loss) since they were taking a medication which was so effective in lowering the cholesterol.​..