“The currently published evidence is insufficient to establish that routine use of GEP testing provides additional clinical value for melanoma staging and prognostication beyond available clinicopathologic variables,” they argued.
Patients must be protected “from potentially inaccurate testing that may provide a false sense of security or perceived increased risk” that could lead to the wrong decisions, they said in a consensus statement from the United States’ national Melanoma Prevention Working Group. The statement was published on July 29 in JAMA Dermatology.
The GEP test for melanoma that is available in the United States – DecisionDx-Melanoma from Castle Biosciences – checks the expression levels of 31 genes reported to be associated with melanoma metastasis and recurrence. It uses quantitative reverse transcriptase and polymerase chain reaction on RNA from formalin-fixed, paraffin-embedded biopsy specimens.
The test stratifies patients as being at low, intermediate, or high risk. It is marketed as a guide to whether to perform sentinel lymph node biopsies (SLNB) on patients age 55 years or older with tumors less than 2 mm deep and to decide what levels of follow-up, imaging, and adjuvant treatment are appropriate for tumors at least 0.3 mm deep.
Medicare reimburses at $7,193 per test for SLNB-eligible patients.
However, this test is not endorsed by the American Academy of Dermatology or National Comprehensive Cancer Network outside of studies because the evidence of benefit is not strong enough, the consensus authors noted.
Even so, use of the test is growing, with up to 10% of cutaneous melanomas now being tested in the United States.
Company welcomes “further discussions”
“To date, thousands of clinicians – over 4,200 US clinicians in the last 12 months – have utilized our GEP test for cutaneous melanoma in their patients after reviewing our clinical data and determining that our test provides clinically actionable information that complements current melanoma staging,” said Castle Biosciences Vice President of Research and Development Bob Cook, PhD, when asked for comment.
Citing company-funded studies, he said that “the strength of the existing evidence in support of these claims has undergone rigorous evaluation to obtain Medicare reimbursement.”
“We believe that the application of the test to help guide [the] decision to pursue SLNB has the potential to realize significant cost savings by reducing unnecessary SLNB procedures, particularly in the T1 population.”
Asked for a reaction to the consensus statement, Dr. Cook said in an interview: “We recently launched two prospective studies with multiple centers nationwide that will involve thousands of patients and provide additional data relating our tests to patient outcomes. ... We welcome further discussions to promote collaborative efforts with centers that are part of the [Melanoma Prevention Working Group] to improve patient outcomes.”
Cart before the horse
Medicare, although it reimburses the test, has its doubts. Due to the “low strength of evidence,” the Centers for Medicare & Medicaid Services said in their local coverage determination that continued reimbursement depends on demonstration of 95% or greater distant-metastasis–free survival and melanoma-specific survival at 3 years “in patients directed to no SLNB by the test compared to standard of care, and ... evidence of higher SLNB positivity in patients selected for this procedure by the test compared to standard of care.”