Long-Term Smoking Increases Risk of Skin Cancer in Women
Because smoking restricts blood vessels, thereby reducing the delivery of oxygen and nutrients, tobacco smoke makes the skin look pale and unhealthy. But cosmetic reasons are not the only reason to quit smoking, as researchers have determined that women who get skin cancer are more likely to have smoked during their lifetime that those who were free from the disease.
Dana Rollinson PhD, an associate member in the Moffitt Cancer Center department of cancer epidemiology, compared 383 patients with skin cancer to 315 people without the disease (355 men and 343 women). The study participants were asked how much they smoked, when they began smoking and the total number of years they had smoked. The researchers analyzed the risks for both non-melanoma skin cancer, which includes squamous cell skin cancer (SCC) and basal cell skin cancer (BCC), and melanoma.
Non-melanoma skin cancer is the most common form of cancer in the United States, where about 2 million cases are treated annually, according to the U.S. National Institutes of Health. Basal cell skin cancer, the more common type, occurs in the epidermis, the top layer of skin. BCC grows slowly and does not normally spread to other organs. Squamous cell cancer is less common but it can spread to other organs.
Melanoma is the most dangerous type of skin cancer. It begins in the melanocytes, which produce a skin pigment called melanin. Although it is not as common as non-melanoma skin cancers, it is the leading cause of death from skin disease.
When evaluated by gender alone, men overall are more likely to get skin cancer than women. The reason for the difference is not known, but Dr. Rollinson suggests two theories. First, "it is possible men's skin is more sensitive to sun exposure than women's." Second, men may be less inclined to use sunscreen or other protection when outdoors.
In terms of tobacco smoke exposure, the more people smoked, the more likely they were to have squamous cell skin cancer, but not basal cell skin cancer. Women, in particular, were three times as likely to develop squamous cell skin cancer the longer they had smoked – especially if they had smoked for a period of 20 years. In men, although their risk was higher in smokers than non-smokers, the researchers found the results to not be statistically significant.
Dr. Rollinson notes that women’s hormones may affect the metabolism of nicotine and the body’s ability to repair damage to DNA, as is the case in lung cancer. "Female current smokers have higher lung cancer risks than men,” she said. “Women have been shown to have more active CYP enzyme activity in the lung, where CYP is responsible for metabolizing 70-80 percent of nicotine. In addition, the up-regulation of CYP by estrogen may play a role."
The study, co-conducted by Moffitt Cancer Center and the University of South Florida, was published online in the journal Cancer Causes Control.
Source: H. Lee Moffitt Cancer Center and Research Institute - Smoking is strongly associated with squamous cell carcinoma among women. (2011, December 8)