Researchers have identified phenotypic markers which may allow for the earlier detection and diagnosis of non-pigmented melanomas.
An international research team, led by University of North Carolina Lineberger (UNC Lineberger) Comprehensive Cancer Center scientists, looked at data from the Genes, Environment, and Melanoma (GEM) international cohort study. The GEM study enrolled patients with incident primary cutaneous melanomas from population-based and hospital-based cancer registries between 1998 and 2003. This new study included 2,387 GEM participants for whom there was data on phenotypes, MC1R genotype, and primary melanomas scored for histopathologic pigmentation, according to a press release from UNC Lineberger on Aug. 9, 2017.
“Amelanotic [non-pigmented] melanoma is linked to worse survival because it’s more likely to be diagnosed at a later stage,” said the study’s senior author Nancy E. Thomas, MD, PhD, a UNC Lineberger member, Irene & Robert Alan Briggaman Distinguished Professor and chair in the UNC School of Medicine Department of Dermatology. “We have identified phenotypic traits that will trigger doctors and patients to pay attention not just to pigmented lesions, but also to these pink spots.”
Using conventional melanoma diagnostic criteria could result in a dermatologist missing a non-pigmented of melanoma as not only does this type of lesion lack the typical pigmented melanoma colour, but its irregular borders and asymmetry may also be harder to detect, said Dr. Thomas.
Investigators evaluated any associations of phenotypic characteristics (freckles, nevi, phenotypic index) and MC1R gene status with incident amelanotic melanomas using logistic regression models adjusted for age, sex, study centre, and primary status (single or multiple primary melanoma).
They found that people who lacked moles on their backs, who had many freckles, and “sun-sensitive” features—including red hair, light-coloured eyes and an inability to tan—had higher odds of developing amelanotic melanoma. In addition, people who previously had this disease were at higher risk, as were people who had variants of the MC1R gene that are linked to red hair.
“If patients have these traits, they need to be more carefully screened,” Dr. Thomas said. “We hope this helps raise awareness for the potential for amelanotic melanoma in this group.”
The findings were published online ahead of print in JAMA Dermatology (July 26, 2017).