Genetic and Molecular Testing Changing How Melanoma Is Diagnosed and Treated

A growing arsenal of genetic and molecular tests is changing how clinicians diagnose and treat melanoma, according to Emily Chu, MD, PhD, assistant professor of dermatology, and pathology and laboratory medicine at the University of Pennsylvania, Philadelphia.

However, she said clinicians must be careful when using many of these new testing kits.

Dr Chu, who spoke about the optimal use of new molecular tests at the American Academy of Dermatology 74th Annual Meeting in March 2016, said a new generation of detection kits offer a wide variety of options.¹

“I think somatic testing for the purpose of detecting actionable mutations is quite accurate, and should be used by clinicians primarily for patients with stage 4 and 3 melanomas. At our institution, there has been some discussion of doing this routinely for high-risk stage 2 patients but I don’t believe that the oncologists are ordering this consistently in that context,” said Dr Chu.

“I think oncologists are quite savvy about BRAF testing. The targeted next-generation sequencing panels generate a lot of information about various mutations in melanomas, but typically have a longer turnaround time than simpler tests like the polymerase chain reaction-based BRAF V600E test. That latter test can typically yield results within 48 hours.”

Dr Chu said she generally doesn’t order gene expression profiling for the purposes of prognostication because of the issue of imperfect sensitivity and specificity. She added that it is difficult to know how to change management of a patient if that patient gets a high-risk (class 2) result despite having an otherwise relatively low-risk melanoma.

“It potentially introduces unnecessary patient anxiety into an encounter,” Dr Chu told Cancer Therapy Advisor. “Gene-expression profiling for both diagnosis of melanocytic lesions and prognostication of definitive melanomas is still at a fairly early stage in my opinion. I think one important point regarding diagnosis using gene-expression profiling is that this should always be taken in the context of the pathologist’s histologic interpretation of the lesion. These tests do not have perfect sensitivity and specificity and so it is another piece of information to be used when rendering a diagnosis.”

Advances in diagnosing and treating melanoma have allowed clinicians to have more tools than ever to treat melanoma and are paving the way towards indidualized care.