is on maximizing survivorship, and so they should be followed closely for recurrence because there is clear evidence early de-tection of recurrence at a time when tumor burden is less leads to better outcomes. I and other leaders in this field recommend in-person examination every three months and radiological surveillance for metastatic disease every six months for four years. The imaging for all patients should consist of a CT scan of the draining nodal basins, chest, and abdomen and also include the pelvis if the primary tumor is in a lower extremity. In addition, I am ordering brain magnetic resonance imaging once a year for high-risk patients, considering data that these individuals have a 14% risk of brain metastasis. 2 technique where one needs time to develop new skills. I believe that any physician who does melanoma surgery should be very comfortable using the DecisionDx-Melanoma test almost im-mediately upon hearing the concept explained and will become more facile integrating it into patient care the more it is used. TDD: Are there cost-effectiveness data for DecisionDx-Melanoma? DR. GUENTHER: I am not aware of any published data, but it is self-evident that DecisionDx-Melanoma is cost-effective con-sidering its impact for reducing the number of unnecessary SLNBs and improving patient survival. The cost of an SLNB is about $30,000, and so every SLNB avoided would pay for six or seven DecisionDx-Melanoma tests. The cost-effectiveness of the test, however, depends on its effect on reducing the number of unnecessary SLNBs, and the available data for DecisionDx-Melanoma show that when used to inform man-agement decisions, it reduces the number of patients with T1-T2 melanoma who undergo SLNB by 30% to 40%. 1 Additional monetary savings come from avoiding unnecessary intensive follow-up with physician visits and costly diagnostic tests for patients identified as having a low risk of metastasis/ recurrence and improving survival of high-risk patients. Fur-thermore, I believe there is unmeasurable value for accurately identifying low-risk patients by being able to tell them that they have a 99+% likelihood of being cured after surgical removal of the primary tumor. Imagine the psychological and emotional burden that is lifted from these patients and their families by hearing this information. TDD: What do studies tell us about the utility of the DecisionDx-Melanoma test? DR. GUENTHER: Studies have all shown that it is highly accurate for predicting outcomes for patients with cutaneous melano-ma and that the information it provides has a positive impact on survival for patients with high-risk disease. Plainly said, having information from the DecisionDx-Melanoma test gives high-risk patients the best chance to live. One of the largest studies assessing the effect of the 31-GEP test on survival of patients with cutaneous melanoma was undertaken as a collaboration between the SEER Program of the National Cancer Institute and Castle Biosciences. 3 The results showed that the 3-year overall survival rate was 1.5% higher among patients who had the 31-GEP test compared to a matched group of untested patients (92.4% vs. 90.9%). At face value, the 1.5% difference in overall survival rate does not sound like much, but it is a threefold greater difference than the benefit found for the Oncotype DX breast cancer gene expression assay that led to its inclusion as recommended testing in National Comprehensive Cancer Network Breast Cancer Guidelines. TDD: What role will GEP testing play in the future for patients with a cutaneous malignancy? DR. GUENTHER: Physicians need to get comfortable using GEP tests to understand tumor biology, predict outcomes, and guide personalized management decisions because they rep-resent the present and the future for patient care. A test for predicting the risk of squamous cell cancer (SCC) metastasis (DecisionDx-SCC) in patients with one or more risk factors is already available, and others will be coming. SCC is respon-sible for more deaths annually than melanoma, and there is clear evidence that DecisionDx-SCC has value for informing decisions on need for adjuvant radiation therapy. REFERENCES 1. Guenther JM. Prospective validation of the i31-GEP for cutaneous melanoma to select patients who may consider foregoing SLNB. Presented at the 2024 annual meeting of the Society of Surgical Oncology, March 20-23, Atlanta, GA. 2. Hasanov M, Martin B, Hasanov E, et al. The 31-GEP to identify patients with localized cutaneous melanoma at the highest risk of metastasis to the central nervous system. J Clin Oncol . 2024;42(16 Suppl):9530. 3. Bailey CN, Martin BJ, Petkov VI, et al. 31-gene expression profile testing in cutaneous melanoma and survival outcomes in a population-based analysis: A SEER collaboration. JCO Precis Oncol . 2023;7:e2300044. Dr. Guenther serves on the Speakers Bureau for Castle Biosciences. TDD: How is the DecisionDx-Melanoma test done? Is there a learning curve for interpreting the report? DR. GUENTHER: The testing process is simple. The order for the test, the patient’s insurance information, and a preprinted letter explaining what the test is for, are transmitted to Castle Biosciences, and the company takes care of the rest. Castle reaches out to the pathology lab to obtain a tumor sample and then performs the testing. The report is generally sent out within three to five days after tissue receipt (within two weeks from the date the order is submitted). The cost is cov-ered by Medicare and most private insurers, and the company offers an industry-leading patient assistance program. There is a short learning curve for interpreting the informa-tion in the test report and applying it to patient care decisions. However, the latter step is straightforward and almost algo-rithmic so that it is very different from learning a new surgical 2 | The Dermatology Digest
The Dermatology Digest Innovations in Personalized Medicine November/December 2024 Supplement: Page 2
