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When possible, breast cancer patients undergo a type of surgery that's designed to conserve as much of their breast tissue as possible. Hypofractionated radiation therapy, also called hypofractionation, can be used as a follow-up therapy for many of these patients. Like conventional radiation therapy, the aim of hypofractionation is to destroy cancer cells in the breast, but with larger radiation doses in fewer overall sessions. Whereas conventional radiation typically requires 25 to 30 sessions, hypofractionation requires 15 to 19.

Our multidisciplinary teams of specialists meet weekly to discusses whether a particular patient will benefit from
hypofractionation or conventional radiation. 

Who is eligible for hypofractionation?

At Yale Medicine, breast cancer patients who receive hypofractionation are typically women ages 50 and older who have had breast conservation surgery (also known as lumpectomy or partial mastectomy) and don’t require treatment to the surrounding lymph nodes.

How does hypofractionation work?

Hypofractionation is a form of external beam radiation therapy  that emits high-energy X-ray beams carefully aimed at the breast. Conventional radiation is delivered through the same machine, but tumors receive a higher dose of radiation per treatment session with hypofractionation.

Hypofractionation is one part of the typical treatment regimen for breast cancer, which also includes surgery to remove the tumor (lumpectomy) and sometimes chemotherapy (in which drugs that kill rapidly reproducing cancer cells are administered intravenously).

What are the advantages of hypofractionation?

The major advantage is convenience because patients can receive the full course of radiation treatment in fewer sessions. With both conventional and hypofractionated radiation, the patient receives radiation five days a week. In the conventional regimen, though, the schedule lasts for five to six weeks, whereas hypofractionation therapy is completed in three to four weeks.

Two large clinical trials found no loss of therapeutic effectiveness in hypofractionation despite its shorter length of treatment. One of the studies also found that swelling of the breast post-treatment (breast edema) as well as skin irritation, skin itchiness and fatigue were less common among women who received hypofractionation compared to other forms of radiation therapy.

What should patients receiving hypofractionation expect?

Patients receiving hypofractionation at Yale Medicine come for care on an outpatient basis five days a week, from Monday to Friday. Treatment session take 15 to 30 minutes, but the majority of that time is spent positioning the radiation machine so it is angled correctly, and getting the patient properly aligned. The actual radiation time is about two to four minutes.

Patients typically lie on their backs at a slight angle, with the arm on the side of the body being treated placed out of the way of the radiation beam. In some cases, patients may be treated lying on their stomachs.

What are potential side effects of hypofractionation?

As with any form of radiation therapy, a common side effect of hypofractionation is some degree of skin irritation, much like a sunburn. Usually, skin irritation flares up during treatment; sometimes, it arises after. Some patients also get an itchy, bumpy rash in the area where the radiation hit the skin, which usually starts near the end of treatment.

Another common side effect is fatigue, which usually builds as treatment progresses. 

Scar tissue may also potentially form in the breast after radiation treatment, particularly in and around the surgical site. The breast may feel a little firmer or bumpier there. In a minority of women, scar-tissue formation from the combination of surgery and radiation can distort the shape of the breast. “But something on the order of 85 percent of women are happy with their cosmetic outcome,” says Suzanne Buckley Evans, MD, MPH, a radiation oncologist in the Department of Therapeutic Radiology.

There is also a small risk of developing a second cancer from the radiation. “This is a possibility with any form of radiation, whether it’s from the sun, a chest X-ray, a mammogram, a CT scan or a radiation treatment,” says Dr. Evans. “It’s a very, very small risk, and the benefits of radiation far outweigh the small association with second cancer.”

How is Yale Medicine’s approach to hypofractionation for breast cancer unique?

Yale Medicine patients receive highly personalized care from a team of cancer specialists. Each week, those specialists meet to discuss all of the patients who are about to start treatment, and those who have just begun. The team discusses whether each patient will benefit from hypofractionation or conventional radiation, and the patient’s overall treatment plan. “There’s lots of peer review, lots of discussion among the group and lots of experiences shared,” says Dr. Evans.

Doctors develop a treatment course based on each patient’s individual case, and informed by all available medical evidence. Input from patients is also sought. “Ultimately, this is a shared conversation and decision that the clinician has with the patient,” Dr. Evans says. “There is a certain amount of this that’s personalized based on both the patient’s and the clinician’s values, and on the clinician’s experience treating people with that particular regimen.”