The identification of patients that should receive genetic testing and the specific genetic tests that should be ordered for those patients are evolving, as the understanding of predisposition to melanoma and the relationship between melanoma and other cancer risk improves.
“Genetic testing, although incredibly helpful for a small number of people, is not something that is frequently indicated for melanoma patients,” says Sancy Leachman, M.D., Ph.D., a professor and chair of dermatology at Oregon Health and Science University in Portland. “The people who are good candidates for melanoma genetic testing are very few, relative to the entire population of melanoma cases.”
In an interview with Dermatology Times following her presentation on genetic testing at the American Academy of Dermatology (AAD) annual meeting in March, Dr. Leachman says that one of the major benefits of melanoma genetic testing is being able to identify people at risk.
“Identifying the individuals who carry a causal melanoma mutation allows these patients to be screened for other cancers, like ocular melanoma or pancreatic cancer, before those cancers develop,” Dr. Leachman says. “It is important to catch these cancers at their earliest stage, before they become life-threatening.”
Melanoma risk may mean risks for other cancers
For example, a patient who carries a cyclin-dependent kinase inhibitor 2A (p16) mutation “is not only at risk for melanoma, but they may also be at risk to a lesser extent, but still at a relatively high rate, for pancreatic cancer,” Dr. Leachman states.
A p16 mutation-carrying patient has a roughly 70% lifetime risk of developing melanoma, but also about a 20% lifetime risk of developing pancreatic cancer.
“However, pancreatic cancer requires a different screening protocol,” Dr. Leachman says. An individual with a p16 mutation “would benefit from screening for pancreatic cancer, too, because it is a lethal cancer that you would almost never detect early enough to be life-saving if you were not screening for it.”
Patients who receive a positive genetic test report are also more likely to participate in its prevention and early detection activities, thus enhancing compliance with medical recommendations for photoprotection and for self-screening and for physician visits.
Tailored screening is another advantage of melanoma genetic testing. For instance, if a patient has a mutation in the BAB1 gene, this patient would not have an increased risk of pancreatic cancer, but would have an increased risk for ocular melanoma and mesothelioma, and screening for the right cancers can be performed.