Chicago — Gene expression profiling with a commercially available test (DecisionDx-Melanoma, Castle Biosciences) provides useful prognostic information for patients with high-risk cutaneous melanoma who undergo sentinel lymph node (SLN) biopsy, and particularly for those found to be node-negative, according to a study presented at the annual meeting of the American Society for Clinical Oncology.
The gene expression profile (GEP) test is a signature of 31 genes — 28 discriminating gene targets and three control genes — that classifies tumors into two groups representing a high and low risk of metastasis (Classes 1 and 2, respectively). A previous validation study demonstrated that it accurately predicted the five-year risk of metastasis for primary cutaneous melanomas.
This second validation study investigated its performance for predicting distant metastasis-free survival (DMFS) and overall survival in a cohort of 217 patients with cutaneous melanoma who underwent SLN biopsy. The study results showed GEP testing provided clinically significant information independent of sentinel node status.
“It is important to point out that the GEP test does not take the place of SLN biopsy. Rather, it is another tool for gaining additional prognostic information about patients,” said lead author David Lawson, M.D., who is professor of hematology and oncology, Emory University, Atlanta.
“SLN biopsy is still the best test we have to predict recurrence in a cutaneous melanoma patient who is clinically node-negative,” he says. “However, my experience as a medical oncologist and the results of the Multicenter Selective Lymphadenectomy Trial show that about two of three patients that eventually develop distance metastases had a negative biopsy.”