New Study Links Nicotine Exposure to Breast Cancer Metastasis

While it is widely known that smoking may lead to the development of certain cancers, less is known about the relationship between nicotine consumption and cancer. The current study specifically looked into the role of nicotine in breast-to-lung metastasis.

Diane Caruana

January 23, 2021

Cigarette smoking has been associated with a higher incidence of breast cancer spread, or metastasis, lowering the survival rate by 33% at diagnosis, however little is know about the role of nicotine in this. Titled, “Nicotine promotes breast cancer metastasis by stimulating N2 neutrophils and generating pre-metastatic niche in lung,” a study published in the January 20 online edition of Nature Communications, found that nicotine may promote the spread of breast cancer cells to the lungs.

The research team found a higher incidence of lung metastasis in both current and former smokers.

“Our data shows that nicotine exposure creates an environment in the lungs that is ripe for metastatic growth,” said lead study author Kounosuke Watabe, Ph.D., who is a professor of cancer biology at the Wake Forest School of Medicine at Wake Forest Baptist Health.

A total of 1,077 breast cancer patients were included in the study, and the research team found that both current and former smokers had a higher incidence of lung metastasis in comparison to never smokers. Subsequently using a mouse model of breast cancer metastasis, the researchers found that persistent exposure to nicotine generates an inflammatory microenvironment in the lungs.

The researchers found that even after quitting nicotine for 30 days, the incidence of distant metastasis was not reduced, suggesting an ongoing risk for breast cancer patients who are former smokers. “Based on these findings, breast cancer patients should opt for smoking cessation programs that do not use nicotine replacement products,” said Watabe. “Furthermore, our findings show that salidroside may be a promising therapeutic drug to help prevent smoking-induced breast cancer lung metastasis, although more research is needed.”

Vapour contains less carcinogens than smoke

Meanwhile, other studies have suggested that the cancer risk from vaping is significantly lower than that from smoking. A study titled, “Comparing the cancer potencies of emissions from vapourised nicotine products including e-cigarettes with those of tobacco smoke,” carried out by Dr William E Stephens from the University of St Andrews in the UK, had analysed the risks from inhaling vapor, in comparison to those from inhaling smoke.

The cancer risk for several nicotine-containing aerosols were modelled, using published chemical analyses of vapour emissions and their correlational risks, and then compared them to analyses of cigarette smoke.

“The aerosols form a spectrum of cancer potencies spanning five orders of magnitude from uncontaminated air to tobacco smoke. E-cigarette emissions span most of this range with the preponderance of products having potencies<1% of tobacco smoke and falling within two orders of magnitude of a medicinal nicotine inhaler,” reported the study.