Early stage colon cancer is often surgically resectable. If you have early colon cancer, you will most likely have a surgery to remove the tumor from your body. Subsequent to surgery, your doctor may prescribe certain adjuvant i.e. additional or helper therapy to attack any last few tumor cells.  MSI (Microsatellite Instability) testing is a measure of how well the tumor is likely to respond to chemotherapy. In addition, it is also a marker of response to immunotherapy. In certain cases, immunotherapy may be considered in the pre-surgery i.e. neoadjuvant setting, in order to facilitate better outcomes from surgery. Strand’s genetic tests can help determine if your tumor is MSI-high or low.

In late stage colorectal cancer, in addition to chemotherapy, targeted therapy is also frequently administered. Genetic testing of the tumor tissue can inform decisions about the choice of targeted therapy given. If you have locally advanced or metastatic colon cancer, your physician will recommend genetic testing for a few genes that can help decide which targeted therapy is most likely to be effective. Then biomarkers graph above shows the genes that are relevant for targeted therapy selection in colorectal cancer. Strand’s genetic tests can determine if any of these genes are mutated in your tumor.

Another class of drugs which is used in colorectal cancer is immunotherapy. Immunotherapy drugs help in activation of the immune system so that it can fight the cancer and have been seen to be very effective in certain cases. Immunotherapy can be considered when mutational profiling does not identify key genes with therapeutic targets. There are a few markers for assessing potential  response to immunotherapy. Some of these are MSI (Microsatellite Instability)  and TMB (Tumor Mutational Burden). Microsatellite instability and Tumor Mutational Burden are measures of a tumor’s immunogenicity, or foreignness in a sense, that can be measured by genetic profiling. A high MSI or TMB score indicates that the chances for a favorable response to immunotherapy are higher. Your doctor might order these tests if he or she is considering an immunotherapy regimen for you.

Sometimes a tumour, despite being given appropriate treatment, does not respond well to the therapeutic regimen. In such cases you and the clinician might want to consider other targeted therapy options if available. It may be useful to profile these tumours with a broad large panel of genes that are mutated across a variety of cancers as there may be a possibility that one of them is also mutated in your tumour. If such a gene is identified, it may open up additional avenues of treatment with targeted therapy. Hence,you and your doctor may consider Strand’s large panel genetic tests for such cancers if you would like to explore other potential treatment options. Large panel testing can also help determine your suitability for immunotherapy by measuring the Tumour Mutational Burden (TMB) and Microsatellite Instability (MSI). Both these are a measure of the immunogenicity of the tumour i.e. how well it can be recognized and attacked by the immune system. Large panels can also be used at the outset if you are interested in comprehensively understanding a tumour’s genetic makeup before starting treatment.