The National Lung Screening Trial (NLST), a protocol with over 50,000 former or current smokers between ages 55 and 75, justifiably became a major news story when the results demonstrated a significant improvement in lung cancer-specific and all-cause mortality of 20% and 6.7%, respectively. However, now even a year after the initial press releases about the positive results and several months after its publication in the New England Journal of Medicine (marking it as a practice-changing finding), CT screening for lung cancer hasn't yet become routine practice. Why not? In contrast with screening results in breast or colon cancer, where positive results have led to a change in policy, the cost of implementing a broad screening policy today entails a public debate about the feasibility, which largely centers around costs.

In this context, a paper by McMahon and colleagues in the Journal of Thoracic Oncology provides a valuable analysis. The authors created a data-based simulation of cohorts of men and women of ages 50, 60, and 70 (six distinct cohorts) with a significant smoking history that would reflect the range of patients included in a screening program instituted based on the NLST. Calculating results based on the data from this simulation, they then analyzed the cost-effectiveness in the common term for this measurement of "costs per quality-adjusted life-year gained ($/QALY)" (essentially, how much does it cost to improve one person's life by a year of functional, "good" time?) for these cohorts when modeling estimated outcomes for CT screening, smoking cessation interventions (with a range of abstinence ranging from 4 to 30% at one year), and a combination of these two approaches.

Why analyze smoking cessation along with CT screening? The premise is that the time of screening for lung cancer provides a "teachable moment" at which patients may be most receptive to careful reflection on the dangers of smoking and the health benefits of quitting. While this could potentially lead to an estimated doubling of the rate of smoking cessation (from a 3% baseline level to 6%) or even better rates of smoking cessation, CT screening could also potentially backfire if it justifies smoking to screened patients who felt that they had "dodged a bullet" -- they might even feel they have license to continue to smoke. If this sounds far-fetched to you, I can tell you that several primary care physicians I've spoken to about lung cancer screening have raised this point as a realistic concern they've encountered.

The modeling exercise varied the data by patient sex, age, frequency of screening and adherence to the protocol, as well as the potential for radiation (i.e., screening)-induced lung cancers. Overall, the analysis provided a wide range of permutations, but a key theme was that CT screening for lung cancer in the population most likely to be targeted provided a benefit in the range of $110,000 to 169,000/QALY, and even higher numbers if adherence was compromised and was more in the real world projected range of 70% compared with the unusually high adherence of clinical trials. To add some context, these numbers are less cost-effective than those associated with screening for breast or colorectal cancer, where the cost-effectiveness ratio falls below $50,000/QALY.

But another key issue is that the efficacy of smoking cessation combined with CT screening could markedly improve the cost-effectiveness to below $75,000/QALY if the intervention provided an opportunity to double the rate of smoking cessation. On the other hand, if it actually had the opposite effect and led smokers to justify their ongoing smoking and halved the background rate of smoking cessation, this could nearly negate the benefits of screening and markedly lower cost-effectiveness.

It's appropriate to recognize that this research is based on modeling from data with many assumptions, but it highlights how overwhelmingly important an intervention like smoking cessation, with a cost-benefit as low as $12,500/QALY, can be when compared with the interventions that are more newsworthy but more can't be considered as compelling when considering the cost-benefit analysis. This paper highlights that we need to notice the low-hanging fruit that remains unpicked.

I know that I don't do enough for my patients in terms of counseling and intervening to encourage smoking cessation. As we swing for the fences with molecular targets and envision eradicating all lung cancer when it is still an asymptomatic subcentimeter nodule detected by screening, it's helpful to remind ourselves that small ball, doing the mundane but high yield activities well, is a winning strategy.