NCCN Guidelines Adds New Test to Predict Melanoma Metastasis Risk

For patients diagnosed with cutaneous melanoma, the path forward often involves a difficult choice: whether or not to undergo a sentinel lymph node biopsy (SLNB). While this surgical procedure is viewed as the gold standard for determining if cancer has spread, it is invasive and carries risks such as infection and lymphedema.

Now, a significant update to the National Comprehensive Cancer Network (NCCN) Clinical Practice Guidelines in Oncology is offering clinicians and patients a more precise way to navigate this decision. For the first time, the NCCN has recommended a molecular test to assess metastatic risk: the Merlin CP-GEP test by SkylineDx.

Better matching therapy to the patient

In a recent interview, Dr. Alexander Meves, a dermatologist at the Mayo Clinic in Rochester, Minnesota and a key figure in the development of the test, highlighted how this inclusion marks a paradigm shift in melanoma management.

"The idea is to better match therapy to the patient," Meves explained in an interview with CURE. "Merlin can really help the majority of patients, who are diagnosed with early-stage disease, make that decision: Do they really need to undergo all that staging and surgery, or can they get by with less while getting the same outcomes?"

The Merlin CP-GEP test combines clinical and pathological factors, like patient age and tumor thickness, with a gene expression profile (GEP) to calculate the likelihood of nodal metastasis. According to Meves, the ability to "rule out" patients who do not need surgery is the test's greatest strength.

Reducing unnecessary surgeries

The clinical implications are vast, particularly for older populations where surgical risks are heightened. Meves noted that, depending on the specific patient population, the Merlin test could potentially help avoid 60% to 90% of unnecessary SLNB surgeries.

The key to this reduction is the test’s high negative predictive value (NPV). This means that if the test identifies a patient as low risk, there is a very high degree of certainty that the cancer has not spread to the lymph nodes.

"While maintaining that oncologic safety, we can rule out the majority of patients," Meves said. "We aren't ruling out too many patients who actually do have metastasis."

Why the NCCN recommendation matters

The NCCN guidelines are the "north star" of sorts for oncologists. Their endorsement of Merlin sets it apart from other commercially available GEP assays. The panel explicitly stated that other tests for SLNB risk prediction are not recommended outside of clinical trials.

This distinction is rooted in the MERLIN_001 study, the largest prospective trial for a molecular test in melanoma. The study demonstrated that patients identified as "high risk" by the test were approximately three times more likely to have a positive sentinel lymph node than those identified as low risk.

The bottom line for patients

For the melanoma community, this news represents a move toward more personalized, less invasive care. By integrating molecular insights into routine practice, doctors can now identify who truly needs surgery and who can safely skip it.

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