Scientists have found the strongest evidence yet of a link between smoking and a common form of skin cancer.
The team from QIMR Berghofer Medical Research Institute studied nearly 19 thousand people and found that current smokers were significantly more likely to develop a squamous cell carcinoma (SCC) of the skin than non-smokers.
It is the most comprehensive and highest-quality study that’s been conducted into the link between smoking and skin cancer. The findings have been published in the Journal of Investigative Dermatology.
The study involved 18,828 Caucasian Queenslanders aged 40 to 69 who had never been diagnosed with a skin cancer. Ten per cent of the group were current smokers, 35 per cent were former smokers, and 55 per cent had never smoked.
Professor David Whiteman and his colleagues tracked how many common skin cancers the group developed over three years.
“We found that current smokers were at significantly higher risk of SCC than former smokers or people who had never smoked,” Professor Whiteman said.
“In contrast, we found no evidence that smokers had higher risks of BCC than non-smokers.
“We also found that among the smokers and former smokers, their risk of skin cancer wasn’t affected by how long they’d smoked for, how heavily they’d smoked, or the length of time since they’d quit.
“We don’t yet understand how smoking might increase the risk of SCC, but these findings strongly suggest that by quitting, smokers are lowering their risk of SCC to the same level as someone who has never smoked. This is another good reason to quit.”
SCCs and BCCs are the most common forms of cancer worldwide. SCCs are generally more serious than BCCs.
While ultraviolet (UV) exposure is the biggest risk factor for developing these common skin cancers, these findings suggest that smoking could also play a role. A number of previous studies have examined the relationship between smoking and common skin cancers, but the findings to date have been conflicting and inconclusive.
“Unlike previous studies, we controlled for a range of established risk factors including skin colour and history of sun exposure,” Professor Whiteman said.
“A consensus is starting to emerge that smoking has very different associations with SCCs and BCCs.
“There are several possible biological explanations as to how smoking might cause skin cancers, but none of those explains why it would apply only to SCCs and to current smokers.
“This is an area in which more research is needed.”
The study was funded by the National Health and Medical Research Council (NHMRC).