Lung cancer from smoking

The Abramson Cancer Center of the University of Pennsylvania
Last Modified: May 8, 2013

Question

Does stopping smoking and/or drinking significantly improve lung cancer outcome? If a patient stops smoking after diagnosis, does his/her prognosis improve? Does smoking or drinking interfere with any cancer treatments? If a patient is terminal, will he/she then be permitted to smoke? At what point is the lung cancer patient allowed to smoke again? I would appreciate your thoughts on these questions. Thanks!

Answer

Barbara Campling, MD, Medical Oncologist, responds:

Does stopping smoking or drinking significantly improve lung cancer outcome? First, with regard to smoking: A large number of studies have shown that former smokers have a better clinical outcome than continuing smokers with lung cancer, as well as a variety of other cancers. There are many possible explanations for the improved survival of non-smokers and ex-smokers compared to continuing smokers with cancer. There are many substances in tobacco smoke, including nicotine, that can promote the growth of cancer and decrease the effectiveness of treatment. Furthermore, ongoing smoking is associated with an increased incidence of other diseases, such as chronic obstructive lung disease and cardiovascular disease, which can further contribute to a worse outcome.

Studies on the effect of alcohol on lung cancer outcome have been inconclusive. I would expect that alcoholics would have a poorer outcome for a number of reasons. Heavy users of alcohol tend to be malnourished and in generally poor physical condition. This could decrease their survival and their tolerance of therapy.

If a patient stops smoking after diagnosis, does his/her prognosis improve? Most of the studies have looked at the outcome of patients according to their smoking status at the time of diagnosis. Many patients quit shortly after diagnosis, and I expect that this would probably improve their chances. Other patients find it extraordinarily difficult to quit. Smoking is a powerful addiction, and most patients with lung cancer have smoked heavily for many years. I encourage all active smokers to quit if possible, and I offer them counseling and medication (e.g. varenicline, the nicotine patch, bupropion, etc.). If they still cannot quit, I do not push it much further.

Does smoking or drinking interfere with any cancer treatments? There are many reasons why smokers and drinkers would be expected to have a worse outcome with treatment. Heavy smokers often have low oxygen levels, and this could increase surgical morbidity and mortality, and it can also decrease the effectiveness of radiotherapy treatment. Carcinogens present in cigarette smoke could cause the tumor cells to be resistant to chemotherapy. Heavy alcohol consumption could affect the metabolism of chemotherapeutic drugs and either reduce their effectiveness or increase their toxicity.

If a patient is terminal, will he/she then be permitted to smoke? At what point is the lung cancer patient allowed to smoke again? I do not insist that these patients not smoke (unless they are on oxygen). If they are forced to quit, they may experience withdrawal symptoms, such as agitation, difficulty concentrating, and an intense craving for cigarettes. When these unpleasant symptoms are added to the symptoms caused by the tumor and the unpleasant side effects of treatment, they could make the patient extremely miserable. This goes against the goals of treatment, which are to alleviate symptoms and make the patient comfortable.