Radiation therapy: What it is and what to expect

More than half of cancer patients will receive radiation therapy, but what is it? Does it hurt? And what are the side effects?

We spoke with Cullen Taniguchi, M.D., Ph.D., to answer some common questions about radiation therapy. Here’s what he had to share.

How does radiation therapy work?

Radiation therapy uses high-energy waves, like those used with an X-ray, but at a higher energy that damages tumor cells’ DNA. The tumor cells die, but the surrounding normal tissues heal themselves.

When is radiation therapy typically used?

There are three ways radiation is used. Most commonly, radiation is used before surgery to shrink a tumor so that it’s easier to remove. We also give radiation after surgery to help destroy any remaining cancer. And when tumors can’t be easily removed with surgery, we’ll use radiation instead.

What are the different types of radiation therapy?

Brachytherapy allows us to put radiation up close to the tumor. But we can only do this safely with a few tumor types, such as with prostate cancer, cervical cancer and breast cancer.

A second type of radiation uses photons, which you may know as X-rays. We first identify the tumor’s location with a CT scan. Then, we develop a plan to ensure as little normal tissue is exposed to radiation as possible. Intensity-modulated radiation therapy (IMRT) is a type of photon therapy that uses a powerful computer to help develop the treatment plan. The computer uses multiple angles to identify the best approach to kill the tumor and limit exposure to normal tissue. IMRT is used when a tumor is close to sensitive organs, such as with anal cancer where the tumor is near the small intestine and genitalia.

The third type of radiation therapy is proton therapy. It’s different from other types of radiation in that the energy waves don’t pass through your body and instead stop at the tumor site. This limits radiation exposure to healthy tissues. Currently, proton therapy is used to treat prostate cancer, lung cancer, head and neck cancers, liver cancer, bile duct cancer and pediatric tumors.

What should I expect the day of my first radiation?

It’s just like getting a CT scan. You’ll walk into a large room that has a table and an open-air machine. The machine is equipped with cameras and microphones so we can talk during the treatment. You’ll lie down on a table, and the machine will circle around you. You won’t ever see the radiation, and you won’t feel it at your first treatment. 

What are common radiation therapy side effects?                                                                                          

Side effects depend on the site of your radiation, but a universal one is fatigue. My patients say they feel like they need an extra nap in the afternoon, and I say listen to your body.

Some patients also have nausea, and we have good medications to provide relief. Other common side effects include skin redness and diarrhea.

Some side effects don’t show up until some time has passed -- in some cases years. In terms of long-term side effects, patients may also experience skin changes, such as hardening and darkening, at the site of treatment.

The patients that do the best are those who get ahead of the symptoms, so talk to your care team early on about possible side effects.

What lifestyles changes should I make while receiving radiation therapy?

Focus on good nutrition. You’ll need to consume more calories than usual to fuel the body’s work of repairing any damage to normal tissues surrounding the treatment site.

Unfortunately, it’s very common to not have an appetite because of the cancer or the treatment, but I tell patients to think of food as a prescription. You need to get the right nutrition to help with healing. If you’re an MD Anderson patient, ask for a referral to see one of our dietitians if you’re having trouble eating.

I also recommend patients be as active as their bodies will let them. Staying active is good for the body and the mind, though this isn’t the time to start a new fitness regimen.

What’s new with radiation therapy?

One innovation is stereotactic radiation, which is a form of IMRT. It allows us to safely deliver a radiation at such as high dose that we can shorten the length of treatment to as little as one week, and sometimes even one day. By reducing the treatment period, a patient can receive radiation during a “down week” of their chemotherapy schedule. It’s more convenient, and it can cost less than standard radiation treatments. Stereotactic radiation is already being used for lung cancer and tumors in the brain and spine. We’ll be opening a clinical trial very soon to see if it’ll also work on other diseases.

We’re also looking into how immunotherapy can work with radiation. After radiation, a tumor remains in the body as scar tissue and is slowly removed by the immune system. We’re exploring how to combine our treatments with immunotherapy drugs to trigger the immune system to fight tumors. We hope to start enrolling patients in our clinical trials soon.

Request an appointment at MD Anderson online or by calling 1-877-632-6789.