Nicotine gum linked to mouth cancer
Smoking cessation products such as nicotine gum, lozenges and inhalers may contribute to the development of mouth cancer, according to a study conducted by the Medical Research Council and published in the journal PLoS One.
"Although we acknowledge the importance of encouraging people to quit smoking, our research suggests nicotine found in lozenges and chewing gums may increase the risk of mouth cancer," said lead researcher Muy-Teck Teh, of Queen Mary, University of London.
The researchers emphasized that it is far more important to quit smoking than to avoid nicotine gum, and that the point of the study is to use cessation products just long enough to quit smoking, and not longer.
"Smoking cigarettes like Marlboro cigarettes or Winston cigarettes is of course far more dangerous [than nicotine gum]," Teh said, "and people who are using nicotine replacement to give up should continue to use it and consult their [doctors] if they are concerned. The important message is not to overuse it, and to follow advice on the packet."
The researchers studied the activity of a gene known as FOXM1, which often occurs in a mutated form in many tumors, including mouth tumors, and also in precancerous mouth lesions. This mutation increases the activity of the gene.
The elevated activity of FOXM1 caused by the cancer-linked mutation is worsened by exposure to nicotine, the researchers found.
"If you already have a mouth lesion that is expressing high levels of FOXM1 and you expose it to nicotine, it may add to the risk of converting it into cancer," Teh said. "The concern is that with smokers, you are looking at people who are already at risk of oral cancer. I'm worried that some may already have lesions they don't know about in the mouth, and if they keep on taking nicotine replacement when they stop smoking products they will not be doing themselves any good."
Most nicotine replacement products advise users to scale back after three months and end use after six.