Exposure to environmental tobacco smoke during chemotherapy
Dear OncoLink "Ask The Experts,"
I have a friend who is undergoing chemotherapy for breast cancer following a mastectomy. I have a problem with her family's continued smoking in the home and car with her. I have been looking for some research that I could show them demonstrating that passive smoke is harmful to chemotherapy patients. Can you point me in the right direction?
Barbara Campling, MD, Medical Oncologist at the Abramson Cancer Center of the University of Pennsylvania, responds:
It is not surprising that you have a problem with your friend's family smoking in the home and car with her. You would probably have a problem with this even if your friend did not have breast cancer. Your question is whether there is any evidence that her exposure to environmental tobacco smoke will be harmful while she is on chemotherapy.
There is really nothing in the medical literature which specifically addresses this issue. However, there are some publications in related areas which may give some clues. Is your friend herself a current or former smoker, and if so, is this in any way related to her breast cancer diagnosis? There have been dozens of studies examining the question of whether active or passive smoking increases the risk of breast cancer. Here are two review articles (1; 2), as well as a recently published study on this subject (3). The results are inconclusive at best, with some studies showing a positive association of breast cancer risk with active smoking, others showing no association, and others showing a protective effect. The bottom line is that there may be a slightly increased risk of developing breast cancer in current or former active smokers compared to never-smokers. There is not likely any significant effect of passive smoking on breast cancer risk.
Does passive smoking increase the toxicity or decrease the effectiveness of chemotherapy? There are no studies of which I am aware which answer this question. However, there is abundant evidence in a variety of cancers (including lung, breast, colon, prostate, cervix, kidney, head and neck cancer and melanoma) that never-smokers or ex-smokers have a better survival than continuing smokers. For example, a recent study of small cell lung cancer patients showed that those who stopped smoking prior to receiving chemotherapy and radiation survived longer than those who continued to smoke (4). In all these studies, the effect of active smoking on outcome was significant, but relatively small. Since the exposure to tobacco carcinogens is much lower in people exposed to environmental tobacco smoke, I would not expect to see any effect of passive smoking on cancer survival.
I think it is unlikely that her relatives are doing any measurable harm to your friend by smoking in her presence. However, they are certainly harming themselves. Should they stop smoking? Absolutely! How can you approach them about this? This could be a difficult situation. You should remember that smoking is a very powerful addiction, and smoking cessation is an enormously difficult process. External stresses (such as a cancer diagnosis in a family member) will make it even more difficult for them to quit. Most smokers know they should stop, and want to quit but are unable to do so. Simply telling them to quit is not likely to have any effect. The motivation will have to come from them. They should consult their physician about medications to help with smoking cessation and smoking cessation support facilities which are available in your area. It won't be easy for them.