Smoking more than triples the risk of developing squamous cell carcinoma, one of the most common forms of skin cancer, researchers from the Netherlands have shown.
A link between smoking and this common form of skin cancer has previously been made, but this is the first study to quantify a "substantial" risk, said the study’s co-author, Jan Nico Bouwes Bavinck, MD, of the Leiden University Medical Center.
"Everybody realizes that sun exposure is a risk for skin cancer, but almost no one knows that smoking is also an important, and independent, risk factor," he said. "Smoking is now associated with an increasing number of cancers beyond lung cancer, such as bladder, head and neck, cervical, and skin cancer."
His team of researchers compared the risk of smoking in 580 patients with different types of skin cancer, and in 386 people without skin cancer. The researchers found that smoking was only associated with development of squamous cell carcinoma, not basal cell carcinoma or melanoma.
The researchers concluded that current smokers were 3.3 times more likely to develop the cancer, and that the risk dropped to 1.9 in former smokers. They also demonstrated a clear relationship between the number of cigarettes smoked and cancer risk. Those who smoked 1-10 cigarettes daily had a risk of 2.4; smoking 11-20 cigarettes a day increased the risk to 3.0, and those who smoked 21 or more cigarettes a day had a risk of 4.1. Pipe smokers were also at increased risk, but cigar smokers were not.
Although the researchers do not know why smoking increases the risk of that particular skin cancer, they theorize it damages DNA in skin tissue, leading to errant cell growth.
"Relation Between Smoking and Skin Cancer;" J.N. Bouwes Bavinck, MD, et al.; Leiden University Medical Center, Leiden, the Netherlands. Vol. 19, No. 1, (January) 2001, pp. 231-238.
Journal
Journal of Clinical Oncology