Understanding Precision Medicine in Cancer Treatment
Precision medicine is an approach to patient care that allows doctors to select treatments that are most likely to help patients based on a genetic understanding of their disease. This may also be called personalized medicine. The idea of precision medicine is not new, but recent advances in science and technology have helped speed up the pace of this area of research.
Today, when you are diagnosed with cancer, you usually receive the same treatment as others who have same type and stage of cancer. Even so, different people may respond differently, and, until recently, doctors didn’t know why. After decades of research, scientists now understand that patients’ tumors have genetic changes that cause cancer to grow and spread. They have also learned that the changes that occur in one person’s cancer may not occur in others who have the same type of cancer. And, the same cancer-causing changes may be found in different types of cancer.
The Promise of Precision Medicine
The hope of precision medicine is that treatments will one day be tailored to the changes in each person’s cancer. Scientists see a future when patients will receive drugs that their tumors are most likely to respond to and will be spared from receiving drugs that are not likely to help. Research studies are going on now to test whether treating patients with drugs that target the cancer-causing genetic changes in their tumors, no matter where the cancer develops in the body, will help them. Many of these drugs are known as targeted therapies. Our section on Targeted Therapy has more information about these treatments.
Though experts believe that precision medicine can become an additional option for people with cancer, it is not likely to replace the cancer treatments we already have. Currently, if you need treatment for cancer, you may receive a combination of treatments, including surgery, chemotherapy, radiation therapy, and immunotherapy. Which treatments you receive will depend on the type of cancer, its size, and whether it has spread. With precision medicine, if your cancer has a genetic change that can be targeted with a known drug, you may also receive that drug.
There are drugs that have been proven effective against specific genetic changes in certain cancers and approved by the FDA. Many of these drugs are discussed in Targeted Cancer Therapies. Approved treatments should be available wherever you have cancer treatment.
Precision Medicine as a Treatment Option
Even though researchers are making progress every day, treatment using precision medicine is not yet part of routine care for most patients. Many new drugs used in precision medicine are being tested right now in clinical trials. Some clinical trials are accepting patients with specific types and stages of cancer. Others accept patients with a variety of cancer types and stages. To be eligible for precision medicine trials, your tumor must have a genetic change that can be targeted by a drug being tested.
Not Every Person with Cancer Will Have Their Cancer Tested for Genetic Changes
If there is a targeted drug approved for your type of cancer, you will likely be tested for a genetic change that might be driving it. For instance, people with melanoma, some leukemia's, breast, lung, colon, and rectal cancers usually have their cancers tested for certain genetic changes when they are diagnosed. Since additional genetic changes that can drive cancer may occur over time, you might also have your cancer tested if it comes back or gets worse.
If there is not an approved targeted drug for your type of cancer, you still may be tested for genetic changes. For instance, your cancer may be tested to see if you can join a precision medicine clinical trial.
How Genetic Changes in Your Cancer Are Identified
To figure out which genetic changes are in your cancer, you may need to have a biopsy. A biopsy is a procedure in which your doctor removes a sample of the cancer. This sample will be sent to a special lab, where a machine called a DNA sequencer looks for genetic changes that may be causing the cancer to grow. The process of looking for genetic changes in cancer may be called DNA sequencing, genomic testing, molecular profiling, or tumor profiling.
Paying for Precision Medicine
If you have a type of cancer with a genetic change that can be treated with an approved drug, testing for genetic changes in your cancer is part of routine care. Therefore, your insurance company may cover the costs. To make sure, check with your insurance company to find out which costs it will cover.
If you join a precision medicine clinical trial, the cost of testing for genetic changes may be covered by the organization sponsoring the trial. To be sure, check with the trial staff and make sure that you understand your consent form.
If there is not an approved targeted drug for your type of cancer and you are not in a clinical trial using precision medicine, your insurance company will probably not cover the costs of having your cancer tested for genetic changes.
Testing for genetic changes requires the use of complex technology and requires the services of people with specialized training. Therefore, this testing can be expensive.
Treatment using precision medicine can also be expensive.
It takes many years, sometimes decades, of research to develop drugs that target the changes that cause cancer to develop, grow, and spread. So, by the time these drugs are available on the market, they are often very expensive.
Precision Medicine Research Moving Forward
Researchers have not yet discovered all the genetic changes that can cause cancer to develop, grow, and spread. But, they are making progress and discover new changes every day. Information from this research is being collected in databases where researchers from across the country can access the data and use them in their own studies. This sharing of data helps move the field of precision medicine forward.
Once genetic changes are discovered, another active area of research involves looking for drugs that can target these changes, then testing these drugs with people in clinical trials. Clinical trials are going on across the United States. To find out if there are open trials for which you may be eligible, use the search tool at Find a Clinical Trial. Or, contact the Cancer Information Service for help.
Researchers are also working to understand and solve the problem of drug resistance that can limit how well targeted therapies work. Many researchers believe that precision medicine is the key to unlocking these secrets.
SOURCE: National Cancer Institute – November 16, 2016