Can quitting smoking after lung cancer diagnosis improve survival?

Most smokers dread lung cancer. They are aware that by continuing to smoke the chances of developing lung cancer are increased 20 times, and that once it has developed the treatment is unpleasant and prognosis poor. Many patients (and unfortunately many clinicians) assume that once you have lung cancer it is too late to quit.

This week a new report was published in the BMJ, based on a review of the evidence that smoking cessation after diagnosis of a primary lung tumour affects prognosis. The study, by Drs Parsons, Daley and Aveyard at the UK Centre for Tobacco Control Studies, combined the data from 10 studies. They found that those who quit smoking after diagnosis were significantly less likely to develop another tumor and significantly more likely to still be alive 5 years later. For example, it was estimated that among 65 year-old patients newly diagnosed with early stage non-small cell lung cancer who continue to smoke, 33% will survive for 5 more years, whereas for those who quit smoking, 70% will survive for at least 5 years.

There are a few pieces of information contained in this paper that are quite striking. The first is the proportion of patients who quit after lung cancer diagnosis. Of 1295 smokers newly diagnosed with lung cancer in this study, only 4640 (49%) quit smoking post diagnosis. If anything, that is likely to be an overestimate of the quit rate, as abstinence was generally based on self-report with no biochemical verification. It is remarkable that less than half of the smokers with lung cancer managed to quit.

The other amazing fact mentioned in the paper was that the authors could not find a single randomized controlled trial testing the effect of smoking cessation on prognostic outcomes in lung cancer. Billions of dollars have been spent on (largely fruitless) new drug development and evaluation for lung cancer, and in the past 50 years not one single cancer research center was funded to do a proper trial to find out whether tobacco dependence treatment improved clinical outcomes! Amazing.

But the good news from this study is that smoking cessation has relatively large clinical benefits even after lung cancer diagnosis.

I wonder what proportion of newly diagnosed smokers with early-stage lung cancer are provided with state-of-the-art smoking cessation treatment?

You can access the full research paper by Parsons and colleagues by cutting and pasting this link into your browser:

If you want to find out more about smoking and smoking cessation, type your search terms into the “Search Health Experts” box on the right.
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About the Author

MA, MAppSci, PhD

Dr. Jonathan Foulds is an expert in the field of tobacco addiction.