Radiation Therapy for Breast Cancer: A Beginner's Guide


Quick summary

When it comes to making breast cancer treatment decisions, radiation therapy is one of the most difficult areas to understand and cope with. Even some oncologists may not be fully familiar with the latest procedures available. Here's a guide to help you prepare for a discussion with the oncologist about what kind of treatment to choose for breast cancer.

Ask the right questions

Radiation therapy procedures are highly technical, which makes some of the concepts downright intimidating. What's more, a host of technological innovations over the past five years (with more coming quickly from clinical trials now underway) means there are many more options to sort through.

But don't let intimidation keep you from asking tough quesitons. Ask the doctor as many questions as you need to until you understand how the recommended procedures work. "It's very important to ask what techniques are being used and why," says oncologist Shalom Kalnicki, chairman of radiation oncology at Montefiore Medical Center and the Albert Einstein College of Medicine in New York.

Here's a guide to the range of treatment options available. For help discussing these options with your doctor, see 8 Questions to Ask About Radiation Therapy for Breast Cancer.

Internal radiation therapy for breast cancer

Radiation therapies can be internal or external. Doctors may recommend internal radiation, also called brachytherapy, when the goal is a high dose of radiation delivered internally to a small area, as in the treatment of breast cancer. The radiation is implanted or injected in the form of wires, "seeds," or capsules, then left in place for a period of time, either until it's removed or until it decays and becomes inactive.

Brachytherapy is usually done as an outpatient procedure, though it's also common to have a radioactive source implanted at the end of surgery. The root word brachy means "short distance," and brachytherapy can be thought of as concentrated radiation from a short distance. Intracavity brachytherapy indicates that the doctor places the radiation into an existing cavity, while interstitial brachytherapy is the term for placing the radiation directly in tissue. MammoSite brachytherapy is a relatively new procedure used to treat breast cancer in which radiation is delivered in the form of a balloon catheter. The balloon is surgically placed where the tumor was removed, and seeds of radiation are delivered through the catheter into the balloon.

Intraoperative radiation therapy, or IORT, refers to radiation that's delivered to the area where a tumor was removed immediately following surgery. This treatment method is common following lumpectomy. Doing this allows the radiation source to be positioned exactly where it will do the most harm to cancerous tissue, while nearby organs and healthy tissue are protected with shields. New portable radiation units now make it possible for IORT to be completed in the operating room at the end of a surgical procedure. Brachytherapy is the most common form of IORT, but for some types of cancer, doctors use external electron beam radiation immediately after surgery.

External radiation therapy for breast cancer

External radiation covers all types of therapy in which radiation is beamed into the body from an outside source, most often an X-ray machine or linear accelerator. It's usually given in the form of a sequence of treatments, typically five days a week for six to eight weeks, with weekends off to give the body time to recover. In recent years, doctors have developed another radiation schedule for women whose lives won't accommodate a six-week radiation schedule. Known as "accelerated breast irradiation," it usually involves giving higher doses of radiation over a shorter period, such as for three weeks rather than six.

Radiation can be done before a tumor is surgically removed in order to shrink it, or after surgery to catch stray cancer cells, or it can be used as a stand-alone therapy.

Standard radiation therapy, which has been in use in various forms for more than two decades, is a form of external radiation that uses large cross-firing beams from an X-ray machine or linear accelerator to target the tumor and the edge of surrounding tissue, sometimes called the margin. Many hospitals now offer a variety of more advanced radiation techniques, such as 3-D conformal radiation therapy (known as 3D-CRT), in which MRIs and other computer imaging techniques are used to map the tumor three-dimensionally so that the beams of radiation can more closely match the outlines of the tumor and damage less of the surrounding tissue.

In recent years, new computer-assisted imaging techniques, new radiation machines, and other technological advances have vastly increased the number of options available under the umbrella of external radiation. For more specific information about choosing or advocating for the latest advances in radiation therapy for breast cancer, see Guide to Intensity-Modulated Radiation Therapy and the Latest Technology.