Timothy L. Cannon, MD, is board certified in medical oncology, hematology and internal medicine. His specialty is managing gastrointestinal cancers. Dr. Cannon emphasizes personalized care for his patients and is interested in pharmacogenomics as well as using technology to improve patients’ access to care. Read Dr. Cannon’s profile.

Many patients that are receiving chemotherapy ask me, “What side effects am I going to have?” This question causes me some anxiety. I don’t actually know what side effects any individual will have, because it varies so much from person to person. Mr. Jones may lose his hair but have no nausea, while Mrs. Fitzgerald may keep her hair but lose her appetite. In the earlier days of chemotherapy, doctors could only offer a guess based on data from clinical trials.

Chemotherapy Side Effects: The Science of Prediction

Anticipating the side effects an individual will experience is not a perfect science. However, we now have some tools to make our guesses much more educated. There is a growing field called pharmacogenomics that allows us to predict more precisely what side effects an individual may have.

What is Pharmacogenomics?

Pharmacogenomics is the study of how human genes affect a person’s response to medications. There has already been significant research into some of the differences in genes that can affect how one person will tolerate chemotherapy. However, as genomics expert Dr. Eric Topol laments in this article, oncologists very rarely use these tools.

I agree that in some cases, it would be useful for physicians to have more training in using these tools. However, there are also good reasons not to use some of the available tests, because the value of these predictive tests is still questionable.

Chemotherapy Research: Predicting Patients’ Tolerance

Inova is committed to elevating the discussion about predictive tests, since many people would value information about how they will handle cancer treatments. Through the Inova Translational Medicine Institute (ITMI), we are now testing genes that can help predict a person’s tolerance to common chemotherapy medications used to treat gastrointestinal cancer.

Pharmacogenomics: Different Dosing of Treatment for the Same Disease

We have also developed a more complex algorithm that involves testing six genes to help guide individualized dosing in colon cancer. Those who participate in our clinical trial (which we hope to open by the end of the year) may find that their dose varies slightly from other patients with the same disease. This is because those patients may have a different set of genes that are known to affect how the body reacts to chemotherapy.

We are hopeful that this will lead to more appropriate and personalized dosing for everyone in the future.



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