Moles are among the strongest risk factors for melanoma, the deadliest form of skin cancer and one of the seven most common cancers in the U.S. Previous studies have linked having a greater number of moles to an increased risk of melanoma and physicians and patients might have relied on total number of moles as an indicator for determining a patient’s risk status.
A study was published this week in JAMA Dermatology where researchers sought to understand the relationship between the number of moles and tumor thickness better. They looked at 566 patients with melanoma to examine the association between age and the number of moles and atypical moles, or moles that looked different from ordinary, non-melanoma moles, and to explore whether there was a relationship between total number of moles or atypical moles and tumor thickness.
What they found seemed to contradict commonly held beliefs. Most patients with melanoma had few moles and no atypical moles. Sixty-six percent of patients had 20 or fewer moles. In patients younger than 60 who had more than 50 moles researchers found that the tumors were thinner than those with fewer moles, which means that the cancer has not gone as deeply into the skin and is less severe.
“The new study serves as a reminder that even people who don’t have many moles or other known risk factors for melanoma may still get the skin cancer,” the researchers said, according to a Live Science article.
The article went on to discuss the complexity of melanoma risk factors. Harvard lecturer and study author Alan C. Geller explained that although family history is a risk factor, many people who get melanoma have no family history of the disease and, although sunburn increases risk, many people who’ve had sunburns will never develop melanoma.
In the end, the take-away is that people need to pay attention to how their moles look and watch out for changes in them. According to the Live Science article, researchers found that people who had five or more atypical moles had a higher risk of thicker melanoma (more than 2 mm thick). People who begin to see any changes in a mole, “should watch it and make sure their doctor — their primary-care physician or dermatologist — takes a good look at it,” Geller said in the article.
This is the same advice that was given in conclusion after reviews of another study published in JAMA Internal Medicine a few years ago, which analysed a different potential melanoma risk factor. When researchers concluded that Viagra might be associated with an increased risk of developing melanoma, it was recommended physicians might want to screen for cancer prior to prescribing the drug and men who had used the drug were cautioned to pay attention to sun exposure and be aware of the appearance of their moles.
Melanoma is one of only three cancers with an increasing mortality rate for men.