The Benefits of Precision Medicine in Cancer

By Robert Dillard - October 29, 2021

Precision medicine, often referred to as personalized medicine, is a form of medicine that utilizes information about an individual’s genes or proteins to prevent, diagnose, or treat disease, according to the National Cancer Institute. It allows health care providers to analyze a patient’s genetic makeup and develop the best plan of attack against that person’s disease to render optimal outcomes.

Precision medicine in oncology uses specific information pertaining to a patient’s tumor to diagnose, treat, and assess the treatment of various cancers. Physicians use precision medicine to discern people who might be at risk for cancer, identify cancer in its early stages, prevent some forms of cancer, choose the best treatment option, and evaluate how treatment is working.

How Exactly Does Precision Medicine Benefit Cancer Treatment?

As explained by one of the nation’s premier cancer centers, MD Anderson, chemotherapy traditionally works by killing cells that rapidly mutate, cancerous or not. Targeted therapy, which is a form of precision medicine, operates by halting or slowing the proliferation of cancer cells.

To survive and thrive, cancer cells feed off specific molecules, in the form of proteins. These molecules are produced by both the genes that produce cancer, and the cells themselves. Enter the functionality of precision medicine techniques. “Targeted therapies are designed to interfere with, or target, these molecules or the cancer-causing genes that create them. In some cases, the drug will attach to the molecule it targets, stopping it from doing its job. Other times, the drug will physically block the molecule from the place it normally goes. By stopping the normal work of these molecules, cancer’s growth can be slowed or even stopped,” MD Anderson writes.

Targeted therapies can be administered either via pill or infusion, and if needed, in conjunction with treatment modalities, such as chemotherapy or immunotherapy.  In precision medicine, the main two targeted therapy drugs used are:

  • Small molecule drugs: Drugs that enter the cell and impede cancer-supporting molecules.
  • Monoclonal antibodies: These are larger and work outside of cancer cells. They target molecules on the surface of the cancer cells or nearby. These are made using cloned cells that produce antibodies that interfere with the targeted molecule.

The Benefits of Precision Medicine

More Emphasis on Prevention

Precision medicine allows for the use of molecular markers that alert cancer risk prior to clinical manifestations. They enable physicians to focus on prevention and early intervention as opposed to reacting to cancer once it has already progressed, at which point, the prognosis is worse. As an example, women with certain BRCA1 or BRCA2 gene variations face an 85% lifetime risk of breast cancer, and up to a 60% chance of ovarian cancer. Precision medicine helps by way of BRCA1 and BRCA2 genetic testing, which can guide preventive measures, such as increased frequency of mammography, prophylactic surgery, and chemoprevention.

Enhanced Treatment Accuracy

Up to half of cancer patients fail to respond to first treatments they are prescribed. Data show these differences in response are attributable to genes that code for drug-metabolizing enzymes, drug transporters, or drug targets. Genetic and other forms of molecular screening therefore enables the physician to select an optimal, precision therapy the first time, thus avoiding costly trial-and-era and improving outcomes.

Avoids Adverse Drug Reactions

Studies show that over 5% of all hospital admissions are associated with adverse drug reactions (ADRs). ADRs are caused by gene variations that code for drug-metabolizing enzymes, such as cytochrome P2C9 (CYp2C9). Precision medicine yields more precise drug dosing, thereby attenuating the risk of potentially fatal ADRs.

Increases Treatment Adherence

Precision medicine can actually enhance treatment regimen adherence. When patients know they are genetically predisposed to certain cancers, it can provide the impetuous to enact life changes to possibly reduce their risk. Data reveal patients with a genetic diagnosis show more than 86% adherence to their treatment program after two years, compared to only 38% prior to testing.

Provides Alternative Uses for Drug Candidates

Cancer therapies used on broaden population may show lesser efficacy as opposed to a drug candidate targeted at a specific, well-defined genetic population.

A medicine that may show weaker efficacy in a more generalized patient population may exhibit greater benefits when its use is limited to genetically defined patient populations. An online example comes in the form of a lung cancer drug (gefitinib) which failed to demonstrate an improvement in survival in a general study population, and was subsequently pulled from the market. The article also noted that using precision medicine yields a response in about 10% of patients who test positive for epidermal growth factor mutations, once again demonstrating the usefulness of this personalized modality.

Overall, precision provides clinicians new tools, know-how, and therapies to discern the optimal therapy for their patients. No longer a concept, its applicability is providing fresh insights into the mechanisms that help cancer cells proliferate, and as the field continues to advance, the likelihood is high of markedly increasing cancer prevention, and enhancing cancer outcomes.

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