Traditional vs. Precision Medicine: How They Differ

Medically Reviewed by Sabrina Felson, MD on June 10, 2022
5 min read

Western or conventional medicine and precision medicine are two approaches doctors use to treat disease. They work in different ways.

With Western medicine, drugs and other therapies are designed to treat large groups of people with the same disease -- like diabetes or cancer. They may factor in your sex, age, or weight, but overall, many doctors base your treatment on what’s most likely to work for everyone with a similar illness.

But not everyone responds to a treatment in the same way. Some drugs work very well for certain people. Others don’t help at all or cause harmful side effects. Finding the exact drug that works for you can involve a lot of trial and error.

Precision medicine takes things a step further. Doctors examine your genic profile and consider your lifestyle and environment, while looking at the characteristics of your disease to determine the best treatment that would most likely work for you. Because it’s so closely tied to who you are, precision medicine is sometimes called personalized medicine.

One current use for this is a targeted therapy to treat a specific type of cancer cell, like those in HER2-positive breast cancer.

In western medicine. scientists develop drugs to treat the symptoms or the disease itself. They test the drugs in clinical trials that involve large groups of people who have that disease. The FDA approves a new drug when studies show that they are more likely to benefit rather than be harmed by the prescribed medicine. Yet, that doesn't mean the medicine will help everyone who takes it.

Precision medicine is much more targeted. Over years of research, scientists have learned more about the genetics behind how diseases start and how they behave.

Many diseases are linked to gene changes. Thanks to the Human Genome Project, researchers now have a map of all the genes in the human body. They can see how certain gene changes cause disease and what makes one person's heart disease, diabetes, or cancer act differently from another's, as well as repond differently to treatment. Knowing how genes and diseases interact can help them fine-tune treatments to make them work better.

For example, we now know that certain gene changes make some cancers grow faster than others. If your tumor cells have these genes then a medication designed to target these genes may be an effective way to slow or stop the cancer. If your tumor cells don't express these genes, then the particular therapy will not be useful in your case. It has dramatically changed the prognosis of certain cancers.

Doctors can use precision medicine to:

  • Learn your disease risk. Testing your genes can reveal which conditions run in your family and how likely you are to get them.
  • Prevent disease. Once you know you carry a certain gene, you may be able to make lifestyle changes or get medical treatment so you don’t get sick. For example, women who carry the BRCA1 or BRCA2 gene mutation are at higher risk for breast cancer. To lower their risk, they may choose to have surgery to remove both breasts, called a mastectomy.
  • Find disease. If you know you're at risk for a certain disease, you can get tested for it. The earlier you find diseases like cancer, the easier they are to treat.
  • Target treatments. Your genetic makeup can help guide your doctor to the drug that’s most likely to work for you and cause the fewest side effects. Precision medicine can even help you decide what dose of a drug you should take.
  • Monitor your response. Doctors can use precision medicine techniques to see how well your condition responds to a treatment.

Precision medicine has a few benefits over traditional medicine.

  1. It can compliment and improve Western medicine. Along with Western medicines, precision medicine adds a unique powerful tool to use our western medications for those who would benefit while sparing those who would not
  2. It's more targeted. Drugs and other traditional medicine treatments are created for and tested on large groups of people. Because they're prescribed so broadly, they don't work for everyone. The average prescription drug may not work well for all the people who take it. Precision medicine can predict if a treatment will work well for you, and if not, your doctor won't prescribe it. So a precision drug is far more likely to be effective against your disease than a drug that treats everyone in the same way.
  3. You won’t be treated with drugs that won’t work. Because the treatment is tailored specifically for your genotype or sequence variants, you won’t be exposed to medications with lower efficacy or a host of medications which may have a potential for greater toxicity.
  4. It likely means fewer side effects. Any drug you take has risks. What makes precision medicine better is that targeted drugs target the abnormal proteins or genes and stop them from making new cancer cells. They don’t affect your entire body. And because you're more likely to find the right drug the first time, you won't have to take as many medicines. The fewer drugs you take, the lower the odds of side effects and complications.
  5. It improves medical decision making. It helps optimize your treatment choices and implement effective disease prevention strategies, including lifestyle, surgical and behavior modifications.

Precision medicine isn't in the distant future. Some examples of treatments already in use today include:

  • Before a blood transfusion, doctors match the donor's blood to the recipient's to make sure the two are compatible.
  • Trastuzumab (Herceptin), a breast cancer drug, is designed to treat women whose tumors have a protein called HER2.
  • The drugs cetuximab (Erbitux) and panitumumab (Vectibix) target epidermal growth factor receptor (EGFR), a protein on the surface of some colon cancer cells that helps the cancer grow. Another example is 50% of melanomas have V600 mutation>BRAF + MEK medications. If your colon cancer has this recptor, then this could be a helpful drug for you.
  • A gene test can predict whether people who receive a heart transplant will reject the transplanted organ.

Researchers continue to collect more and more data about our genes and habits and learn how they interact to affect our health. Thanks to advances in personalized medicine, in the future doctors will be better able to predict whether we'll get sick and to find just the right treatment if we do.