1. What is DecisionDx-UM?
DecisionDx-UM is a gene expression profile test (GEP) that tells you how likely your uveal melanoma is to metastasize, or spread to other parts of the body, usually the liver. This prognostic test was developed by ocular oncologist Dr. J. William Harbour while at Washington University in St. Louis, and exclusively licensed to Castle Biosciences Inc., a Texas company that develops molecular prognostic tests for rare cancers.
The GEP test has been available for routine clinical use since late 2009 and has been adopted by 100 of an estimated 110 ocular oncologists in the U.S. as standard of care in the management of eye cancer.
2. How does the DecisionDx-UM test work?
The DecisionDx-UM test screens the gene expression profile of the uveal melanoma tumor. Specifically, it determines the unique activity of a set of 15 genes to identify the likelihood that the tumor has already spread from the eye.
A small sample of the tumor tissue must be taken before radiation therapy is administered, or from the enucleated (removed) eye. Castle Biosciences’ lab typically reports results within two-three weeks of receiving the tissue sample from the treating physician.
3. What are the possible results from DecisionDx-UM and what do they mean?
DecisionDx-UM can tell you whether your eye tumor falls into one of three Classes, identifying the statistical risk of metastasis over the next five years, the period for which scientific data has been collected. These include:
- Class 1A: Very low risk, with a 2% chance of the eye cancer spreading over 5 years
- Class 1B: Low risk, with a 21% chance of metastasis over five years
- Class 2: Very high risk, with 72% odds of metastasis over five years
4. When is the test performed?
If you choose to have the test, it’s important to know that timing is critical. For patients undergoing radiation treatment, a small sample of the tumor tissue must be taken before surgery with a slender needle since radiation may alter the genes in your tumor and skew the lab results.
If the treatment plan is enucleation, or removal of the eye, the tumor sample can be provided either from a biopsy taken at the time of enucleation, or by obtaining tissue slides from the wax block made following surgery and maintained in the pathology lab.
5. How can I get the test?
The DecisionDx-UM test can only be ordered by your physician or other appropriate healthcare provider—usually an ocular oncologist, retinal specialist, or ophthalmologist.
Currently, a majority of ocular oncology specialists in the country offer DecisionDx-UM to their patients. If your doctor does not perform the test and you would like further information or need help finding a physician who does, you can call customer service at 866-788-9007.
6. Can the test results be used to guide my monitoring and treatment?
DecisionDx-UM results provide critical information for you and your doctor to determine the most appropriate plan for monitoring for metastatic disease and potential treatment. While the test cannot, at this point, guide your doctor toward a specific treatment, two recent studies show that the results are being used to:
- Develop personalized monitoring plans based on a patient’s metastatic risk;
- Initiate referral to a medical oncologist for treatment planning, and
- Refer appropriate high-risk patients to clinical trials.
7. Are there any risks associated with the biopsy procedure?
The DecisionDx-UM test requires a tiny sample of your tumor, commonly taken with a very thin needle (called a fine needle aspirate biopsy or FNAB). If you are having radiation treatment, your doctor must take the sample before surgery.
Thousands of biopsy procedures have been performed safely in uveal melanoma, and the literature suggests that complications are rare. However, as with any surgical intervention, the potential risks should be fully discussed and considered with your doctor.
8. How accurate is DecisionDx-UM?
The DecisionDx-UM test is the most accurate prognostic test for uveal melanoma available. It is the only test that has undergone extensive validation by multiple studies, including an independent, prospective study of 494 patients conducted by the Collaborative Ocular Oncology Group (COOG). The results were published in Ophthalmology in August 2012, and showed that the GEP test could successfully classify tumors more than 97 percent of the time.
9. How does DecisionDx-UM compare to other prognostic methods such as chromosome 3 testing?
The DecisionDx-UM test measures the expression levels of 15 genes whereas the Monosomy 3 test looks to see if one of the chromosome 3 arms has been deleted or lost. In a head-to-head comparison (COOG study described above), DecisionDx-UM was found to be superior to Monosomy 3 testing in predictive accuracy and technical reliability for returning a result.
10. How is the test paid for?
The decision to undergo prognostic testing should be fully discussed with your doctor and loved ones. If you decide you want the information the GEP test provides, it’s important to know that Castle Biosciences has, to date, processed all DecisionDx-UM test orders for U.S.-based physicians regardless of the patient’s ability to pay.
Castle Biosciences works with Medicare, commercial insurance providers and, in some cases, your physician’s institution to secure payment coverage for DecisionDx-UM. Castle submits insurance claims on your behalf and follows through the system to payment. The Company believes a patient’s ability to pay for the test should not affect their care, and has put a generous Patient Assistance Program in place for those who need it.
11. What is the purpose of the Castle Clinical Tissue Repository?
The program allows a DecisionDx-UM patient to store a sample of their tumor tissue free of charge for up to five years. Availability of the tissue for analysis would allow patients to take advantage of emerging targeted treatments, clinical trials, and further prognostic testing as they become available.