DecisionDx-UM is a proprietary gene expression profiling (GEP) test developed by Castle Biosciences, designed to assess the metastatic risk in patients diagnosed with uveal melanoma. Uveal melanoma is the most common primary intraocular malignancy in adults. While local control of the primary tumor is often achievable, a significant proportion of patients develop distant metastases, particularly to the liver, which is often fatal.
The DecisionDx-UM test analyzes the expression levels of specific genes within a patient's tumor tissue, typically obtained through biopsy. Based on these gene expression patterns, the test classifies uveal melanoma tumors into distinct prognostic categories. The most common classifications are Class 1 (low metastatic risk) and Class 2 (high metastatic risk). Some versions of the test may further subdivide Class 1 into Class 1A (very low risk) and Class 1B (intermediate-low risk), providing a more nuanced risk assessment.
The primary purpose of DecisionDx-UM is to provide physicians and patients with objective, personalized information regarding the biological aggressiveness of the tumor. This prognostic information helps to:
- Guide patient management decisions, including the intensity and frequency of follow-up surveillance for metastatic disease.
- Inform discussions about potential adjuvant therapies or enrollment in clinical trials for high-risk patients.
- Aid in avoiding overtreatment and associated costs for low-risk patients.
The test has undergone extensive clinical validation, demonstrating its ability to accurately predict patient outcomes and identify those at highest risk for developing metastatic disease. It has become an important tool in the multidisciplinary management of uveal melanoma, complementing traditional clinical and pathological features.