A design impact study of Castle Biosciences‘ DecisionDx-Melanoma gene expression profile (GEP) test for cutaneous melanoma (CM) was recently published in the journal Current Medical Research and Opinion.
The test by Texas-based molecular diagnostics company Castle is designed to help patients and their doctors make the best treatment and follow-up care decisions based on the individual molecular signature of their tumor by accurately identifying high risk Stage 1 and 2 patients based on biological information from 31 genes within their tumor tissue, predicting metastatic risk independent of current diagnostic modalities including American Joint Committee on Cancer (AJCC) melanoma database staging.
Castle Biosciences explains that provided with additional tumor-specific information revealed by the GEP test, physicians and patients can make better-informed decisions about how aggressively to manage the disease, noting that, for example, most Stage 2 melanoma patients currently receive routine clinical skin and lymph node exams, but are not recommended for imaging such as brain or lung scans, or considered for adjuvant therapy options.
The company suggests that if these Stage 2 patients were identified as having high risk tumor biology, their oncologist might consider upstaging them for active systemic surveillance or referring them to medical oncology for consideration as potential participants in systemic drug therapy or clinical trials.
Similarly, Castle observes that some patients with Stage 1 melanoma, which makes up the majority of all melanoma cases, will experience metastasis of their cancer, yet are treated as low risk. But if they were accurately identified as high risk, they also could be considered for more aggressive monitoring and treatment.
The study, reported in the Open Access journal paper and titled “Clinical impact of a 31-gene expression profile test for cutaneous melanoma in 156 prospectively and consecutively tested patients,“ was designed to ascertain clinical management changes determined by the test outcome, which classifies cutaneous melanoma patients being at low (Class 1) or high (Class 2) risk for recurrence. The investigators reviewed medical charts of 156 CM patients being treated at six institutions (three dermatology and three surgical oncology practices) who were consecutively tested between May 2013 and December 2015.
Clinical management data compiled and compared both before and after the patient received the 31-gene expression test result included frequency of physical exams, frequency and modality of imaging, and referrals to surgical and medical oncologists. Clinical management plans before and after receipt of the DecisionDx-Melanoma test results were collected to assess the impact on clinical decision making.
Forty-two percent of study subjects were identified as Stage 1; 47 percent Stage 2; and 8 percent were Stage 3. Overall, 95 patients (61 percent) were Class 1 and 61 (39 percent) were Class 2. Documented changes in management were observed in 82 (53 percent) patients, with the majority of Class 2 patients (77 percent) undergoing management changes compared to 37 percent of Class 1 patients.
The investigators conclude that molecular risk classification by gene expression profiling can have significant clinical impact, and can influence physicians to direct clinical management of CM patients, with the vast majority of changes implemented after the receipt of test results reflective of the low or high recurrence risk associated with the patients’ molecular classification.
Study results show that genomic classification of melanoma with the 31-gene expression profile test changed clinical management in more than half the tested patients, and changes implemented were consistent with expected use of test results.
The surgical oncologists and dermatologists managing the melanoma patients included in the study were able to use test results to individualize patient management based on biological risk, increasing surveillance intensity in high-risk Class 2 patients, while reducing surveillance intensity in low-risk Class 1 patients while still remaining within the context of established practice guidelines for melanoma patient management.
However, because follow-up data was not collected for this patient cohort, the study is limited as to assessing the impact of gene expression profile-based management changes on healthcare resource utilization and patient outcomes.
“Results of this study support the use of this GEP test as an important tool for guiding follow-up care for patients diagnosed with cutaneous melanoma,” study author Adam C. Berger, MD, chief of surgical oncology and deputy vice chair for clinical research in the Department of Surgery at Thomas Jefferson University Hospital in Philadelphia, said in a release.
“The GEP test’s ability to accurately predict the relative risk of disease recurrence is changing how physicians approach follow-up care, particularly in cases with a Class 2 test result predicting a high risk for future metastatic disease,” he added.
