A Patient’s Guide to Tumor Profiling
Every patient’s cancer is unique. However, the vast majority of cancer patients are still treated as if cancers can be grouped together by the organ of origin (e.g., colon cancer, breast cancer) rather than by looking at each cancer on an individual basis. Personalized medicine considers the uniqueness of each cancer patient’s tumor, and uses the description of mutated genes to define each patient’s unique set of therapeutic targets. In this approach, molecular profiling of the tumor, or tumor profiling, is the first step in the process.
The democratization of high throughput sequencing methods has allowed for the development of many companies offering tests that focus on different cancers and specific sets of genes. These include Foundation Medicine, Caris Life Science, Guardant Health, GenomeDx Biosciences, Intermountain Healthcare, Genomic Health, Trovagene, Varientyx, Invitae, Paradigm, and many others.
However, one size does not fit all, and evaluating the diverse set of molecular profiling tests can be a challenging and time-consuming task. When exploring molecular profiling options, many criteria should be taken into account, including biopsy type, tests offered, cancer type, profiling data type, turn-around time, and insurance coverage.
The first step in the process is a biopsy, in which a sample of tissue, blood, or urine is taken from the patient’s body for analysis. It is important to consider the types of biopsy available, although for some cancer patients, the choice of biopsy maybe be limited to one option. For patients with hematological cancers and bone marrow cancers, a liquid biopsy may be the only viable choice. Conversely, if a patient has recently had surgery to remove some or all of their tumor, it may be best to request that a sample of the tumor be used for tumor profiling rather than performing a second procedure.
Recent studies found both similarities and differences between the results from solid and liquid biopsies to be similar. The pros and cons of different biopsy types are described below.
- Requires removal of tissue from the tumor
- Requires the tumor to be reachable and, its localization, clearly defined
- Provides a sample of the mutations actually found within the tumor
- Detects early-onset tumors for diagnosis and subtyping better than a blood biopsy
- Can miss some mutations that are found in a limited section of the tumor
- May not capture mutations in cancer cells that have spread to other parts of the body, unless the additional tumor locations are known
Liquid biopsy (blood and/or urine)
- Analyzes the circulating cell free DNA (cfDNA) from cells that are shed into the bloodstream and urine by some tumors
- Can capture mutations found in different tumor sites across the body
- Can miss some mutations that are found in a limited section of a tumor
- May not be able to capture mutations in cancer cells if the tumors are not releasing enough cells in the bloodstream
Guardant Health is one of the best-known tumor profiling companies that uses blood biopsies (Guardant360® test). But other DNA testing companies, such as Trovagene, utilize both blood and urine biopsies. Foundation Medicine offers profiling tests that can use either a solid biopsy or liquid biopsy. Most others use solid biopsies only.
Tests Offered & Cancer Types:
Tumor profiling companies use a variety of techniques to analyze the biopsy sample, and return information about the genes altered in the cancer cells. However, some companies only focus on specific cancer types. When selecting a tumor profiling company, it is important to know which types of cancer each company focuses on. Several examples are listed below:
|Company||Tests Offered & Cancer Types|
|Caris Life Sciences||Caris Molecular Intelligence: examines a large series of cancer genes for all cancer types. the biomarkers and technology platforms implemented may vary for each tumor type|
|Foundation Medicine||FoundationOne: for solid tumors except pediatric tumors and sarcomas
FoundationOne Heme: for hematologic tumors, pediatric tumors, and sarcomas
Foundation ACT: for blood biopsies
|Guardant Health||Guardant360: all cancer types except hematological tumors|
|Intermountain||ICG100: examines a large series of cancer related genes for all cancer types|
|Paradigm||PCDx: examines the most genomic variations for all solid tumor types|
|Trovagene||Trovera: examines EGRF, KRAS, and BRAF genes for common solid tumors|
Tumor Profiling Data Types:
Tumor profiling services use varying methods to analyze the patient’s tumor. For instance, some utilize next-generation DNA sequencing or RNA sequencing, while others analyze protein expression. The method used often depends on the biopsy type and nature of the cancer diagnosis. A patient should ask their oncologist about these different technology platforms.
Most tests take an average of about 14 days, following receipt of the biopsy sample, but this can vary. In general, processing of liquid biopsies is faster than solid biopsies.
Costs for molecular profiling range from approximately $3,000 to $7,000; however, this range can vary significantly depending on the company or the number of genes being queried. Most insurance companies now cover molecular profiling tests, but the amount of coverage and the amount of the copay depends on a patient’s insurance provider and whether or not the patient has met the deductible. When a test is covered by insurance, the out-of-pocket cost is generally $500 or less.
If a test is not covered by insurance, the molecular profiling company may appeal to the insurance company on behalf of the patient, or if the claim is denied, the company may agree to significantly reduce the cost for the patient if they pay out-of-pocket. Pricing and insurance information is sometimes available through the company’s website, or may require further inquiry via phone or email.