The research, published in Nature Cancer, is a joint study led by Harvard Medical School in collaboration with researchers from The University of Sydney, Melanoma Institute Australia, Sydney Local Health District and Adaptive Biotechnologies.
The researchers analysed primary melanoma samples (lesions removed from the original melanoma site) from 209 patients, 164 of whom came from Melanoma Institute Australia. In particular, they focused on a subset of immune cells known as T cells.
They found that patients with a T-cell fraction (TCFr or proportion of cells in the lesion that were T cells) of less than 20 percent in their primary melanoma were two-and-a-half times more likely to have disease progression than those with more than 20 percent TCFr.
“These findings suggest analysing TCFr in primary melanomas is a valuable tool for predicting which patients are at risk of developing metastatic melanoma, ” said Dr Wilmott.
“This could help us personalise treatment for each patient based on their individual risk of recurrence and progression, and potentially target them earlier with immunotherapy,”‘ Professor Scolyer added.
Australia has one of the highest rates of melanoma in the world, with one person diagnosed every 30 minutes and one person dying every five hours from the disease.
While 90 percent of early stage melanomas are cured with surgery alone, it will recur metastatically in some patients within five years.
Recent advances in targeted and immunotherapies have significantly improved outcomes for Stage IV melanoma patients. However, the management of primary melanoma has remained relatively unchanged, with prognosis based principally on factors that include tumour thickness and ulceration.
“This test offers the ability to identify primary melanoma patients at high risk of developing metastatic disease at their initial diagnosis,” said Dr Wilmott said. “These patients may benefit from close monitoring or the addition of adjuvant treatments to prevent their disease progressing.”
The test used in the study is commercially available for research use only. The authors also note that the current study is retrospective and further research is needed.
Declaration: Funding for this work was provided by National Institutes of Health (R01 AI127654 and R01 CA203721, the German Research Foundation (grant no. PR 1621/1-1), the Novo Nordisk Foundation and the Lundbeck Foundation. Authors also declare individual supporting grants. Laboratory services were provided at no cost by Adaptive Biotechnologies. Selected authors were employed by and have financial interest in Adaptive Biotechnologies, own intellectual property associated with Adaptive Biotechnologies or serve on their scientific advisory board. Refer to the paper for full details.