St. Jude registry identifies melanoma subgroups, assists in treatment choices
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A pediatric melanoma registry developed at St. Jude Children’s Research Hospital has helped researchers improve the classification of pediatric melanocytic tumors.
The registry, called Molecular Analysis of Childhood Melanocytic Tumors (MACMEL), has enrolled patients since 2016.
“The main difference of this registry from others is that it is prospective, and all of the pathology is reviewed centrally at St. Jude,” Alberto S. Pappo, MD, director of St. Jude Solid Tumor Division, told Healio. “In addition, we obtain yearly follow-up for patients who are not actively seen at our center, and we perform extensive genomic analysis of the lesions to better define the subgroup category, natural history and biology of the lesion.”
A study on the prospective registry, which recently appeared in Cancer, analyzed data from 70 children enrolled in the program.
It found three subgroups of melanoma tumors: conventional melanoma, Spitz melanoma and atypical Spitz tumors, and giant congenital nevus melanoma.
Conventional melanomas often have BRAF and TERT promoter mutations, while Spitz tumors, often occurring in younger patients, typically have kinase fusions involving MAP3K8, NTRK, ALK, ROS1, RET, BRAF or MET. The more aggressive giant congenital nevus melanomas have NRAS mutations according to a press release from St. Jude.
Among the 37 subjects with Spitz melanoma or atypical Spitz tumors, two patients experienced a locoregional recurrence, and none developed distant metastases. Three of 17 patients with conventional melanoma died of the disease despite treatment, and all four patients with giant congenital nevus melanoma died of the disease. In 12 patients with other types of tumors, all survived.
These results can assist clinicians in determining the proper treatment options, according to Pappo. For example, lymph node sampling or dissection and immunotherapy for high risk resected disease may be unnecessary in those patients with tumors that are predicted to have a favorable clinical outcome, but those with aggressive clinical behavior can benefit from more aggressive therapies such as clinical trials of novel agents, he said.
“Our results emphasize and provide the foundation for the future to integrate molecular and clinical data to better inform the treating pediatric oncologist so that therapies can be optimized by limiting unnecessary procedures or treatments,” Pappo said. “Incorporation of genomic information is essential for the accurate diagnosis of pediatric melanocytic lesions, particularly the so-called Spitz category.”