SAN DIEGO -- The use of a 31-gene expression profile (GEP) test resulted in a change in the clinical management of melanoma patients in almost half of cases, according to researchers here.
Specifically, use of the test resulted in a change of patient management in 49% of cases, with changes happening most frequently with patients who were identified as being at high risk of metastasis, reported Robert Cook, PhD, executive director, research and development, of Castle Biosciences in Friendswood, Texas, and colleagues at the American Academy of Dermatology meeting.
Action Points
- Note that this study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
The 31-GEP test, known as DecisionDX-Melanoma, was designed to identify high-risk stage 1 and II patients based on biological information from 31 genes within their tumor tissue.
Previous studies have reported on the clinical impact of the 31-gene GEP test for guiding physician decisions on management of melanoma patients. For example, a found that 53% of patients saw a change in management, while a determined that 47%-50% of physicians changed management plans as a result of the test.
In all of the studies, the most significant changes in management included follow-up frequency and the use of different imaging modalities.
"The current study was designed to evaluate the use of the test and guidance of patient management in a prospective fashion," Cook said.
In this prospective multicenter study, 247 stage I (181) and stage II (66) patients were enrolled at 15 dermatology, surgical oncology, and medical oncology centers.
The patients had clinical management plans documented after their melanoma diagnosis and then underwent 31-GEP tests, after which changes in management plans were documented. Follow-up and surveillance plans pre- and post-test were compared to determine changes in management.
Cook's group found that 49% of patients had their management plans change post-test. Of those patients who were assessed as class 1 (low risk of metastasis) 36% had management plans changed, while 85% of patients assessed as class 2 (high risk of metastasis) had management plans changed.
Overall, 52 cases had decreased intensity of care, 80 cases had increased intensity of care, and 121 cases had no change. Class 1 accounted for 87% (45/52) of cases with decreases in management, while class 2 accounted for 64% (51/80) of cases with increases.
"This indicates that high-risk molecular features are driving many of these management decisions," said Cook. "And that change is really reflected in an increase or decrease in management intensity." He added that intensity of care is indicated by more or less frequent surveillance intervals or the use of more sensitive imaging modalities (such as PET/CT rather than chest x-ray).
For example, follow-up frequency, along with imaging, was the most significantly changed management modality. In the case of class 1 patients, 28 decreased the frequency of the visits, while 13 increased the frequency of their visits. On the other hand, 28 class 2 patients increased the frequency of their visits, while just one saw a decrease in surveillance frequency.
As for imaging, of the 22 class 1 patients who experienced a management change, half saw a decrease in intensity of care, while the other half saw an increase. But the vast majority of class 2 patients (42) who experienced a management change saw an increase in intensity of care compared with just four who saw a decrease in intensity of care.
Cook noted the majority of class 1 cases who experienced an increase in intensity of care also had high-risk clinical features. "This suggested that managing physicians were considering both molecular and clinical features when developing a management plan," said.
Hensin Tsao, MD, PhD, of Massachusetts General Hospital in Boston, noted that while the test detected a change in practice, but asked "does that alter outcomes at the end of the day?" Tsao was not involved in the study.
That "is the million dollar question," according to Cook.
"We would definitely like to connect the changes in management with an improvement in outcomes," Cook told 鶹ý. "That would require a long-term study with well-defined surveillance parameters. Given the wide-range of [National Comprehensive Cancer Network] recommendations for follow-up and surveillance, that study has not been designed yet."
Primary Source
American Academy of Dermatology
Cook R, et al "A Prospective Multicenter Study to Evaluate the Clinical Impact of a 31-Gene Expression Profile Test on Physician Recommendations for Management of Melanoma Patients" AAD 2018.