Personalized Medicine for Cancer

If you or someone you know has cancer, you’ve probably been scouring anything you can get your hands on to find the best way to beat the disease. It’s likely you’ve seen terms like “personalized medicine,” “precision medicine,” or “targeted drugs.”

What are these things? More importantly, can they help you?

Personalized medicine -- also called precision medicine or pharmacogenetics -- is a new way to fight cancer. It uses information about you and your tumor to figure out what’s driving the disease and create a plan just for you.

Genetics as a Teacher

For years, cancer treatment was a cookie-cutter process. You’d have surgery to remove a tumor, then chemotherapy or radiation to kill cancer cells. But blasting cancers with chemotherapy or radiation kills healthy cells as well, which can lead to a host of nasty side effects.

Now, researchers can examine your cancer cells and learn the order of the genes in their DNA. While most cells in your body have identical genes, the ones in cancer cells have mutations, or changes. This is what allows them to grow into tumors.

What’s more, your cancer may have different genetic changes than someone else’s. Scientists also now know that genetically, one person’s breast cancer may be more similar to another person’s stomach tumor than to other breast cancers. This makes the need for personalized medicine even greater.

Matching Patients With Drugs

The FDA has approved more than a dozen drugs that target one of these mutations. They include imatinib (Gleevec), a drug used on chronic myelogenous leukemia, and the breast cancer drug trastuzumab (Herceptin).

Tumor genetics can also tell doctors which drugs won’t work. For example, if your colon cancer has a genetic mutation called KRAS, doctors won’t give you two common colon cancer drugs because they know they won’t work.

Many clinical centers do something called tumor profiling. Your doctor takes a look at your tumor’s genes. If he thinks your cancer may have specific mutations, he might start you on a specific drug that’s approved for your type of cancer.

For instance, if you have breast cancer, a genetic test would tell him if Herceptin might work for you.

Profiling can also help if other treatment options, like chemotherapy, haven’t worked for you. A genetic mutation might point your medical team toward an unexpected drug, like one originally designed for another type of cancer.

Not a Magic Bullet

The personalized approach works better to shrink tumors -- and save lives -- than traditional treatment. But it isn’t always a cure.

Tumors can contain cells with different gene mutations, so a targeted therapy designed to pick off cells with one mutation may work on only part of a tumor. The cells that remain may keep growing.

Talk to your doctor to find out if this approach could work for you.

A New Kind of Clinical Trial

Standard trials to test cancer treatments use people whose tumors are similar in size or location. They might choose only people with stage IV lung cancer, for instance. But now that there's personalized medicine, researchers need new ways to study how targeted treatments work on a variety of cancers.

Basket trials combine folks with many different cancer types into a single “basket” and use a precision medicine approach to find treatments that work. So a single trial could include people on many different drugs.

The creation of new treatments requires a constant back-and-forth between doctors and scientists. New drugs are made to combat new gene changes. Then, they’re tested in the clinic. As tumors change in new ways, more new drugs will become available.

WebMD Medical Reference

Reviewed by William Blahd, MD on August 22, 2016

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