Does nicotine replacement therapy cause cancer (No)?
The Lung Health Study recruited 5887 smokers starting November 1986, and 3923 of them were randomly selected to receive an intensive, state-of-the-art stop smoking treatment (group therapy plus nicotine gum). The participants in the original study were followed for 5 years, and 3320 were included in a longer study focusing on lung cancer for another 7.5 years.
The study presents one of the best opportunities of measuring the known exposure to either smoking, or NRT, or both over a 5 year period, as this information was accurately recorded throughout the study.
The study found that 75 participants were diagnosed with lung cancer and 203 with cancer of any type during the follow-up period. Those with the largest cigarette smoke exposure during the study were significantly more likely to suffer lung cancer, but those who used a large amount of nicotine gum were not at any greater risk of suffering from lung cancer or any other cancer examined in the study.
Even though most of the participants were relatively young at enrollment (just under 50) and so had relatively low risk over the immediately following years, around 3.2% of the heaviest smokers developed lung cancer, as opposed to half that proportion in those smoking less. But the amount of use of NRT during the study was not associated with getting cancer.
The results of this study are consistent with the vast majority of human studies, in that they do not find any convincing evidence to suggest that NRT causes cancer.
Murray RP, Connett JE, Zapawa LM. Does nicotine replacement therapy causecancer? Evidence from the Lung Health Study. Nicotine Tob Res. 2009 Sep;11(9):1076-82. Epub 2009 Jul 1.