This testing helps show the molecular features of your tumor and may reveal changes that can happen over time, including after treatment, that could affect your future treatment options.
Tumor molecular testing is often performed using tumor tissue from a biopsy or surgery. In some cases it can be done through a blood test called a liquid biopsy.
Many patients with metastatic (stage IV) colorectal cancer have this testing done at or near diagnosis.
In colorectal cancer, the most common alterations examined through NGS include:
The list of manufacturers is expanding rapidly, so ask your doctor what they prefer.
Another type of testing available is pharmacogenomics testing.
What are pharmacogenomics? Natural differences in a person’s genes can affect how their body processes certain medications. These tests do not look for cancer-specific genes or test cancer tissue. Instead, they examine genes that control how certain drugs are broken down in the body.
For example, two important genes relevant to CRC looked at by pharmacogenomics testing are DPD and UGT1A1. These genes help the body break down chemotherapy drugs such as 5-fluorouracil (5-FU)/ capecitabine, and irinotecan, respectively. Some people have natural variations in these genes, called gene polymorphisms, that cause these drugs to be broken down more slowly and potentially cause more severe side effects. Patients with these gene variations should receive an adjusted dose.
