In the context of cancer, precision medicine is an approach to healthcare that centers the patient rather than the cancer type. Previous to this framework, patients with the same type of cancer received the same general treatment, whether that was radiation, chemotherapy, or surgery—a “one-size-fits-all” approach. With the rise of precision medicine, we now have new technologies that test patient samples to look for altered genes in the DNA, which could explain the root cause of their cancer. Upon testing an individual with cancer, if an error is found in a known cancer-causing gene, we can then check for treatments or clinical trials with therapies that are designed to specifically target this gene. In the case that a person is tested due to family history, the results allow us to create a plan of action including more frequent screenings to identify cancerous cells sooner if they develop. Precision medicine allows for preventative care, and addresses the problem at its root: the DNA, rather than doing damage control in the general area where the cancer is found. 

This field is constantly evolving as new cancer-causing genes are being discovered and targeted treatments developed; it can be hard to keep up. To learn more about precision medicine and the associated diagnostic tests, read the sections below. 

Comprehensive Genomic Profiling

Comprehensive Genomic Profiling (CGP) involves testing multiple genes at once in what we call a gene panel to look for any abnormalities in the DNA that are known to be cancer-causing. Using this approach rather than a single-gene test is more time-efficient and increases the chance of finding a gene alteration for which a targeted treatment exists. Learn more about comprehensive genomic profiling in this section. 

National and International Advances

Read about where Canada is at in terms of implementing precision medicine (including a provincial readiness report), as well as Belgium, the United States, Israel, and Australia.

New Findings

Given that new discoveries are constantly being made in the field of genetics and precision medicine, we have created summaries of recently published research articles to keep you up to date! We recommend going through our “CGP” and “Biomarker” sections first for the background information before diving into the specifics in this section. 

Biomarkers

“Biomarker” is an umbrella term referring to anything measurable in the body that indicates whether a normal or abnormal process is taking place [1]. It doesn’t only apply to cancer, but in this context, biomarkers are typically used as a sign that there is an error in the body that is responsible for someone developing cancer. Amongst other things, a biomarker can be genetic, meaning it’s an altered/malfunctioning gene, or a protein in the body that isn’t properly performing its role. Running biomarker testing on a tissue sample can help identify the basis of a person’s cancer, which can be hereditary or not. The key takeaway from this is that in biomarker testing you are analyzing the cancer, whereas in genetic testing you are analyzing the person and what their DNA looks like everywhere, not just in the cancerous region (tumour). 

Biomarker testing allows clinicians to better understand what’s going on in a patient’s body and has the potential of opening up more treatment options. Since this concept is still on the rise, it’s unfamiliar to many. Read about biomarkers in general, which ones are associated with which cancers, and more at the link below.

Glossary of Terms

To better grasp the concepts of precision medicine and diagnostic testing, read the following section, where we have defined some key terms.

Actionable biomarker: In the context we are using this term, it typically refers to a protein or a gene that is altered and causing cancer, for which a precise treatment/therapy exists or is undergoing clinical trials. 

Driver mutation: This term describes a mistake within a gene (mutation) that leads to cancer. The mutations screened for in a genetic/genomic panel would be categorized as actionable or driver mutations. The difference between the two is that despite being known to cause one or more types of cancer, driver mutations do not necessarily have an existing treatment created to target them yet [2].

Molecular profiling: Normally the way we categorize tumours is by staining and viewing them under a microscope, but there is so much more going on behind the scenes. There are changes in the DNA/genes that could be causing the tumour; these won’t be seen under the microscope. To get a better picture of what’s going on, molecular profiling is an approach done using gene and protein arrays, which test to see whether certain genes in our body are on or off, if there are errors in them, or if there are any abnormalities with someone’s proteins.

Molecular tumour board: This is a group that comes together after a patient has done a molecular profile/biomarker test (ex: NGS) to interpret their results. They will take that information to match patients to available therapies that are either approved or in clinical trials. These review boards are composed of patient advocates, physicians, health care professionals, and scientists. 

Next Generation Sequencing (NGS): When we think of cancer, we’ve routinely used a light microscope and stained tumour tissue to analyze it. The NGS technology allows us to get even more specific and find the cause of a cancer rather than seeing the outcome (cancerous tissue). That “cause” being something out of place in the genes, which are the “code” to your body.

Pan-cancer analysis: A term used in reference to testing across multiple cancer types, rather than just one. Some cancers, despite being found in different parts of the body, are caused by the same error in the DNA. This is the case for the BRCA gene; it can be responsible not only for causing breast cancer but also melanoma, ovarian, prostate, and pancreatic cancer. These types of tests can be done using next-generation sequencing technology. 

Reflex testing: A process where a standardized set of biomarkers are tested for automatically upon diagnosis to keep things consistent. This approach enables more patients to get tested and increases the efficiency of the process since biomarker test results can then inform the treatment plan [3]. A multidisciplinary team determines the protocol that reflex testing must follow [3].

Refractory cancers: A cancer for which the current treatment approach is unsuccessful, whether that is by being unresponsive to treatment or becoming resistant [4]. These types of cancers would greatly benefit from advancements in the field of precision medicine. 

Tumour agnostic: A term to describe treatments that target a specific biomarker within a tumour rather than its general location in the body. 

[1] FDA-NIH Biomarker Working Group. BEST (Biomarkers, EndpointS, and other Tools) Resource. Silver Spring (MD): Food and Drug Administration (US); Bethesda (MD): National Institutes of Health (US), www.ncbi.nlm.nih.gov/books/NBK326791/

[2] Basharat, S., Farah, K., & Horton, J. (2022). An overview of comprehensive genomic profiling technologies to inform cancer care. Canadian Journal of Health Technologies, 2(8). https://doi.org/10.51731/cjht.2022.414 

[3]  Gosney, J. R., Paz-Ares, L., Jänne, P., Kerr, K. M., Leighl, N. B., Lozano, M. D., Malapelle, U., Mok, T., Sheffield, B. S., Tufman, A., Wistuba, I. I., & Peters, S. (2023). Pathologist-initiated reflex testing for biomarkers in non-small-cell lung cancer: expert consensus on the rationale and considerations for implementation. ESMO open, 8(4), 101587. https://doi.org/10.1016/j.esmoop.2023.101587

[4] NCI Dictionary of Cancer terms. Comprehensive Cancer Information – NCI. (n.d.). https://www.cancer.gov/publications/dictionaries/cancer-terms/def/refractory-cancer