By Lawson Eng, MD, FRCPC, and William K. Evans, MD, FRCPC
Posted: August 21, 2020
IN REFERENCE TO: Cao P, Jeon J, Levy DT, et al. Potential impact of cessation interventions at the point of lung cancer screening on lung cancer and overall mortality in the United States. J Thorac Oncol. 2020. [Epub ahead of print].
Lung cancer screening reduces lung cancer and all-cause mortality and is recommended by the U.S. Preventive Services Task Force for adults between ages 55 and 80 with at least a 30 pack-year smoking history.1 Approximately half of all individuals undergoing screening are current smokers, for whom the screening encounter could be a teachable moment to encourage smoking cessation. The potential effects on clinical outcomes and the cost and cost-effectiveness of integrating a smoking cessation program into lung cancer screening have not been evaluated prospectively.1-3 Until such data are available, policy makers would benefit from estimates of the potential impacts of integrating cessation services into lung cancer screening programs.
In a study reported in the Journal of Thoracic Oncology,4 Cao et al. used a lung cancer screening and smoking microsimulation model to assess the potential effects of combining smoking cessation interventions with lung cancer screening. Their model uses a number of U.S. national databases that include the smoking history of screen-eligible individuals born in 1950 or 1960, coupled with data on the probability of quitting with and without a cessation intervention and on lung cancer risk, treatment effectiveness, and competing tobacco-related mortality. The model simulates the natural history of lung cancer and the outcomes of low-dose CT screening, followup, and treatment.
The benefit of this microsimulation model is that it enables assessment of the impact on clinical outcomes over a range of plausible screening uptake rates and probabilities of quitting. Not unexpectedly, the magnitude of the projected gains increases as both rates increase, and the benefits are potentially large. For example, if 30% of the screen-eligible individuals born in 1950 were screened and 10% of them quit smoking, the number of lung cancer deaths might be reduced by 14% and life-years increased by 81%.
The strengths of this Cancer Intervention and Surveillance Modeling Network model are its inclusion of a simulation of the natural history of lung cancer and the extensive use of U.S.-specific data, making the study results relevant to the U.S. population. One the other hand, the model assumes only a one-time cessation intervention, whereas annual screening provides an opportunity for repeated interventions and quit attempts. Furthermore, only probabilities of cessation between 0% and 30% were modeled. The cessation rate may be higher, as those attending screening programs may be motivated by concerns for their lung health. In a pilot study in Ontario, Canada, more than 80% of patients accepted a referral to cessation services and expressed satisfaction with being referred, suggesting that there is potential for a higher quit rate, although this has yet to be determined.5 Also lacking from this report is information on the cost and cost-effectiveness of the smoking cessation intervention(s).
Currently, the National Cancer Institute is supporting the Smoking Cessation at Lung Examination Collaboration to evaluate the effects on outcomes of pairing smoking cessation interventions with lung cancer screening.6 What is also needed is more information on the most effective cessation intervention(s) for this population (nicotine replacement therapy alone or in combination with counseling or prescribed medications) and how best to deliver these interventions (online or through apps vs. in person). Although clinical trial investigators may dismiss these findings because they are not “real data,” the results are based on solid assumptions derived from real data and provide plausible estimates of potential clinical implications. ✦
About the Authors: Dr. Eng is a medical oncology fellow in the Division of Medical Oncology and Hematology, Princess Margaret Cancer Centre, Toronto, Ontario, Canada. Dr. Evans is professor emeritus in the Department of Oncology, McMaster University, Hamilton, Ontario, Canada.
1. Moyer VA. Screening for lung cancer: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2014;160(5):330-338.
2. Tammemagi CM, Neslund-Dudas C, Simoff M, Kvale P. Smoking and lung cancer survival: the role of comorbidity and treatment. Chest. 2004;125(1):27-37.
3. Taylor KL, Cox LS, Zincke N, Mehta L, McGuire C, Gelmann E. Lung cancer screening as a teachable moment for smoking cessation. Lung Cancer. 2007;56(1):125-134.
4. Cao P, Jeon J, Levy DT, et al. Potential impact of cessation interventions at the point of lung cancer screening on lung cancer and overall mortality in the United States. J Thorac Oncol. 2020. [Epub ahead of print].
5. Evans W, Darling G, Miller B, Cameron E, Yu M, Tammemagi M. Acceptance of smoking cessation services in Cancer Care Ontario’s lung cancer screening pilot for people at high risk. J Thorac Oncol. 2018;13(10):S341.
6. Joseph AM, Rothman AJ, Almirall D, et al. Lung cancer screening and smoking cessation clinical trials: SCALE (Smoking Cessation within the Context of Lung Cancer Screening) Collaboration. Am J Respir Crit Care Med. 2018;197(2):172-182.