Quitting Smoking After Cancer
Freddy Sitas, Marianne Weber, Sam Egger, May Chiew, Sarsha Yap, Dianne O’Connell
Cancer Research Division, Cancer Council NSW, Woolloomooloo, NSW 2011, Australia

Aim
To illustrate the benefits of smoking cessation around the time of diagnosis on cancer survival, using a simple modelling technique.

Background and Methods
Smoking cessation reduces mortality overall, therefore smokers diagnosed with cancer ought to benefit significantly if they quit. However oncologists and cancer control organisations do not often provide smoking cessation support at the time of a cancer diagnosis. This is possibly because there is very little evidence regarding the benefits of smoking cessation on cancer survival.
We calculated 8-year absolute survival of people who quit smoking around the time of a cancer diagnosis (“recent quitters”), ex-smokers, continuing and never smokers using recently published mortality rates and applying these to cancer survival statistics from Australia and the USA.

Results
Eight year absolute survival, across all cancer types, was 37% for smokers, 43% for recent quitters and 49% for never-smokers in Australia, and in the USA was 43%, 49% and 54% for smokers, recent quitters and never-smokers, respectively.

Conclusion
The benefits of quitting smoking after a cancer diagnosis compared to continued smoking are potentially very large. While further larger studies can provide more robust estimates of the effect of smoking cessation on cancer survival, our estimates suggest it is prudent to implement smoking cessation in treatment guidelines as an essential part of cancer care.