SAN DIEGO – , following cancer of the colorectal area, lung and bronchus, prostate, and breast.
“The incidence of melanoma seems to have continued to go up since the early 1990s,” David E. Kent, MD, a dermatologist who practices in Macon, Ga., said at the annual Cutaneous Malignancy Update. “The death rates have been flat and may have slightly decreased.”
In 2023, the ACS estimates that about 97,610 new melanomas will be diagnosed in the United States (58,120 men and 39,490 women), and about 7,990 people are expected to die of melanoma (5,420 men and 2,570 women). In addition, ACS data from 2017-2019 project that about 2.1% of men and women will be diagnosed with cutaneous melanoma in their lifetime. To date, more than 1.3 million people in the United States live with cutaneous melanoma, and the overall 5-year survival is 93.7%.
Epidemiologic studies show an increase in melanoma incidence, primarily among White populations. “This is believed to be due primarily to sun exposure and to changing recreational behaviors and tanning bed exposures,” said Dr. Kent, who holds a faculty position in the department of dermatology at the Medical College of Georgia, Augusta. Increased surveillance and diagnosis also play a role. In the medical literature, annual increases in melanoma incidence vary from 3% to 7% per year, “which translates into a doubling of rates every 10-20 years,” he said, noting that annual melanoma costs are approximately $3.3 billion.
While incidence rates are lower in non-White, non-Hispanic populations, poor outcomes are disproportionately higher in persons of color. Blacks present at diagnosis with more advanced stage disease and are 1.5 times more likely to die from melanoma, he said, while Hispanics are 2.4 times more likely to present with stage III disease and 3.6 times more likely to have distant metastases. Persons of color also have higher rates of mucosal, acral lentiginous, and subungual melanoma.
Known genetic risk factors for melanoma include having skin types I and II, particularly those with light hair, light eyes, and freckling, and those with a family history have a twofold increased risk. Also, up to 40% of genetic cases are from inherited mutations in CDKN2A, CDK4, BAP1, and MCR1. Other genetic-related risk factors include the number and size of nevi, having atypical nevus syndrome, DNA repair defects, large congenital nevi, and a personal history of melanoma.
The main environmental risk factor for melanoma is exposure to ultraviolet radiation. “You can break it down in terms of whether this exposure is lifetime, intermittent intense UV exposure, from the use of tanning beds, or due to sunburns during childhood,” Dr. Kent said at the meeting, which was hosted by Scripps MD Anderson Cancer Center. Other environmental risk factors include distance from the equator, having a high socioeconomic status, being immunosuppressed, and exposure to heavy metals, insecticides, or hormones.
In a recently published study, researchers investigated the risk factors associated with first and second primary melanomas in 38,845 patients who were followed in Australia between 2011 and 2018. During a median follow-up of 7.4 years, 1,212 patients (3.1%) had a single primary melanoma diagnosis and 245 (0.6%) had a secondary primary melanoma diagnosis. The researchers found that second melanomas were more likely than were first melanomas to be in situ; for invasive tumors, second melanomas were more likely to be thin (defined as 1 mm or less) than were first melanomas.
In addition, having many self-reported moles at age 21 years was more strongly associated with second melanomas compared with first melanomas (hazard ratio [HR], 6.36 vs. 3.46, respectively; P = .01), as was having a high genetic predisposition (HR, 3.28 vs. 2.06; P = .03).
Second melanomas were also more strongly associated with a history of multiple skin cancer excisions than were first melanomas (HR, 2.63 vs. 1.86; P = .05). “Interestingly, there were no differences in UV exposure between the first primary and second primary melanoma groups,” said Dr. Kent, who was not involved with the study.
He noted that while sunscreen use protects against melanoma, a National Ambulatory Medical Care Survey (NAMCS) found that internists and pediatricians mentioned sunscreen at fewer than 0.1% of visits – even those with patients who have a diagnosis of skin disease. “Physicians need to do better,” he said. “We as dermatologists have work to do to help educate them.”
Dr. Kent reported having no relevant disclosures.