Effects of Tobacco Smoking and Nicotine on Cancer Treatment

A substantial number of the world's population continues to smoke tobacco, even in the setting of a cancer diagnosis. Studies have shown that cancer patients with a history of smoking have a worse prognosis. Modulation of several physiologic processes involved in drug disposition has been associated with chronic exposure to tobacco smoke. The most common of these can be categorized into effects on cytochrome P450 mediated metabolism, glucuronidation, and protein binding. Perturbation in the pharmacokinetics of anticancer drugs could result in clinically significant consequences, given they are amongst the most toxic, but potentially beneficial, pharmaceuticals prescribed. Unfortunately, the effect of tobacco smoking on drug disposition has only been explored for a few marketed anticancer drugs, thus very little prescribing information is available to guide clinicians on the vast majority of compounds. The carcinogenic properties of multiple compounds found in tobacco smoke have been well studied, however relatively little attention has been given to the effects of nicotine itself on cancer growth. Emerging data are available which identify nicotine's effects on cancer cell apoptosis, tumor angiogenesis, invasion, and metastasis. The implications of such are unclear, but may lead to important questions to be addressed regarding approaches to smoking cessation in cancer patients.