A tattoo might seem like an unlikely place to look for cancer clues, but new research suggests it could be linked to a lower risk of melanoma, the deadliest form of skin cancer.
Scientists from Huntsman Cancer Institute at the University of Utah evaluated 7,000 local people and found a mixed pattern. People who had two or more tattoo sessions were less likely to have both invasive and in situ melanoma, while people with only one tattoo session were more likely to have melanoma, especially in situ.
In situ melanoma means the cancer cells remain on the skin’s surface and are more easily removed.
Study leader Jennifer Doherty said the reasons for the pattern are still unclear.
“We really need to understand how tattoos could impact risk for different types of cancer.
“For melanoma, the results seem to be mixed. But we see people with two, three, and four tattoo sessions having decreasing risk, and that’s a stronger pattern than the increased risk with just one session.”
The findings surprised the researchers because their original idea had been the opposite. Doherty said her team had expected that having more tattoos would increase melanoma risk because tattoo ink contains carcinogens, including metals and other chemicals.
The ink in a person’s skin can also break down over time and create new carcinogens that were not originally in the tattoo. Tattoos can also cause inflammatory responses, and inflammation is often associated with cancer risk.
Study first author Rachel McCarty, a former doctoral student at Huntsman Cancer Institute, said: “The results that tattoos could decrease melanoma risk surprised us. But this isn’t a black and white case of ‘get more tattoos, and you could lower your risk of melanoma.’
“Instead, we need to do more research to understand what we are seeing and if this decreased risk is simply due to behavioral or physical factors, or if there could be beneficial immune responses associated with tattooing, which lower melanoma risk.”
The research team said one possible reason is that people with several tattoos may be more careful about sun safety and may take better care of their skin. The team also suggested tattoos could form a physical barrier that blocks ultraviolet radiation or trigger an immune response against precancerous cells.
Research suggests around one in three people now have tattoos. About 41 percent of Americans under 30 have at least one tattoo, along with 46 percent of people aged 30 to 49.
The stakes are high with melanoma. Localized melanoma has a 99 percent five-year survival rate, but that drops to less than 35 percent if it spreads to distant organs.
McCarty said people with tattoos should still make informed decisions about skin protection.
“Tattoo artists already advise their clients to wear sunscreen and sun protection to prevent tattoos from fading. We know wearing sunscreen is an important safety step for everyone, even without tattoos. But it’s also important for those with tattoos to take extra precautions to prevent any additional harmful components from forming in the skin when pigments break down from UV exposure.”
The researchers also said the lower melanoma risk seen in this study may not apply to other cancers. An earlier project from Doherty’s team and a Swedish study both suggested tattooing could be linked to a higher risk of certain blood cancers.
The melanoma study was published in the Journal of the National Cancer Institute. The research team said the findings are a “promising” step in understanding how tattoos may affect skin cancer risk.
Co-author Douglas Grossman, of the Melanoma Center at Huntsman Cancer Institute, said: “The Mountain West and the area we serve have some of the highest melanoma rates in the country.
“Better understanding risk factors for melanoma will help us improve prevention strategies across the region, advise our patients about risks more accurately, and ultimately save lives.”
