Precision oncology
Breast 2021 U.S. estimates: 284,200 new cases and 44,130 deaths Genetic testing categorizes breast cancer subtypes based on the presence or absence of specific DNA mutations. A recent international study of 110,000 breast cancer patients was able to identify more than 350 genetic changes across nearly 200 cancer-related genes. These findings point to even more precise cancer classification strategies as well as new treatment pathways.
Because each person’s cancer is genetically unique, the one-size-fits-all treatment approach that has been historically followed leads to treatment failure for many patients. Taking a more personalized approach to cancer treatment helps clinicians decide which treatment a patient's tumor is most likely to respond to, sparing the patient from receiving treatments that are unlikely to help. This practice, called precision oncology, involves unraveling a patient’s genetic code and developing a tailored treatment plan based upon the genetic makeup of their cancer. Common treatment options used in precision medicine include targeted therapies, gene therapy, and immunotherapy. Advances in science and medicine have led to the development of many drugs and therapies that target specific parts of cancer cells, like proteins or genes. Some genetic mutations cause cancer cells to produce too much, too little, or mutant versions of proteins that are involved in cancer cell growth, spread, and survival. Targeted therapies, which are usually small molecule drugs or antibodies, target these proteins to kill cancer cells. Targeted therapies are currently FDA approved for more than fifteen different types of cancer. Driver mutations, the main mutation giving cancer a growth and survival advantage, have been identified for many types of cancer. The number of targeted therapies specific to these types of mutations are growing. Over the past five years, the FDA has approved at least three oncology drugs that target key genetic drivers of cancer, rather than specific types of tumors. These ‘tissue agnostic’ therapies are effective against tumors with a specific genetic alteration, regardless of the cancer’s location. They present an example of the amazing advances that are being made in precision medicine. The field of precision oncology is rapidly growing as evidenced by the FDA's approval of ten new precision oncology drugs in 2020. Precision medicines as a whole now account for more than one out of every four drugs the agency has approved in the past six years. The FDA also approved the use of 17 existing precision medicines for new uses to add to the arsenal of available precision drugs . REFERENCES: https://www.fda.gov/news-events/press-announcements/fda-approves-third-oncolo- gy-drug-targets-key-genetic-driver-cancer-rather-specific-type-tumor http://www.personalizedmedicinecoalition.org/Userfiles/PMC-Corporate/file/PM_at_FDA_The_Scope_ and_Significance_of_Progress_in_2019.pdf
Ovarian 2021 U.S. estimates: 21,410 new cases and 13,770 deaths
For most ovarian cancer patients, within 3 years of their initial treatment the cancer has returned. Drugs known as PARP inhibitors have been found to significantly delay the length of time before cancer comes back. The medications are most effective for ovarian tumors with specific genetic mutations that reduce the cell’s ability to repair its DNA. Recent clinical trials suggest PARP inhibitors may be beneficial as a first-line initial treatment in addition to their role as follow-up maintenance therapy.
Colorectal 2021 U.S. estimates: 149,500 new cases and 52,980 deaths
Like many cancers, colorectal cancers are associated with both genetic and epigenetic mutations. Genetic mutations directly alter the DNA instructions (genes). In contrast, epigenetic mutations change how the cell processes the DNA instructions. They often modify a gene’s activity to make more or less of that gene’s protein. These changes cause cells to undergo rapid growth, evade destruction or develop resistance to treatment. Knowledge of these epigenetic pathways has led to a new class of therapeutic drugs called epigenetic modifiers.
REFERENCES: Siegel R.L. et al. Cancer Statistics, 2021, CA: A Cancer Journal for Clinicians . 71:7-33 (2021). https://acsjournals.onlinelibrary. wiley.com/doi/full/10.3322/caac.21654
Precision Medicine in Cancer Treatment: National Cancer Institute graphic
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SCIENCE FOR LIFE
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