Study finds skin imaging can help predict melanoma spread risk

A common, non-invasive skin imaging technique can predict which melanoma patients face a higher risk of metastasis as accurately as current methods that require analyzing tumor samples after surgery.

The research, led by Aimilios Lallas, M.D., Ph.D., of Aristotle University of Thessaloniki in Greece and published in Nature Communications, reported that dermatoscopy, a specialized imaging technique already widely used to diagnose melanoma, identified visual features that predicted metastasis risk. The findings could help doctors identify high-risk patients who need closer monitoring or aggressive treatment while avoiding overtreatment of lower-risk patients, something current staging methods cannot do until after melanoma is surgically removed.

“A predictive model based on these non-invasive features performed as accurately as the current standard,” the study authors wrote.

Dermatoscopy is routinely used by dermatologists to help diagnose melanoma, but it is not currently used to estimate a patient’s risk of recurrence or spread. Existing risk assessments rely largely on lab analysis of tumors after they have been removed.

Researchers analyzed dermatoscopic images from 524 patients diagnosed with melanoma across 10 sites in Europe, South America, Asia, and the United States. The investigators examined whether specific visual features were associated with melanoma spreading to lymph nodes or distant organs. They found that tumors showing a “blue-white veil,” or a bluish area, had a more than six-fold increased risk of spreading, while skin breakdown covering more than half the tumor was associated with a more than three-fold increased risk.

“A plausible explanation is that melanocytes located in the deep dermis are surrounded by a dense vascular network, increasing the likelihood of vascular invasion and subsequent dissemination,” the study authors said. “Additionally, the blue-white veil corresponds to a raised or palpable area of a lesion, often seen in nodular melanomas, which are inherently more aggressive.”

Using these features, the researchers built a prediction model based solely on dermatoscopy. They compared its performance with a model based on standard pathology findings, including tumor thickness and ulceration, which are key elements of current melanoma staging. In testing, the dermatoscopy-based model performed similarly to the pathology-based model. A combined model that used both visual and pathology information showed the highest predictive accuracy.

The researchers also identified protective features. Melanomas with heavy pigmentation covering more than three-quarters of the lesion were associated with substantially reduced metastasis risk compared to tumors with little or no pigmentation.

“In our analysis, heavy pigmentation (primarily brown) was associated with a favorable prognosis, appearing in 73.5% of non-metastatic cases,” the authors wrote. “This relationship may be explained by the fact that heavy dermatoscopic pigmentation reflects increased melanin levels.”

The study also places its findings in the context of evolving treatment practices. Immune-based therapies are now recommended for some patients with earlier-stage melanoma. However, the paper said that approximately 30% of these patients do not experience recurrence despite treatment, while some patients with lower-stage disease do relapse without receiving follow-on therapy. The authors write that more accurate risk assessment tools could help guide treatment decisions.

The research was a retrospective study, and the study authors suggest prospective studies are needed to confirm their results.