Radiation Therapy for Breast Cancer in Men

Radiation therapy uses high-energy rays or particles to destroy cancer cells. Radiation to the breast is often given after breast-conserving surgery to help lower the chance that the cancer will come back in the breast or nearby lymph nodes. This is needed less often for men with breast cancer than it is for women, mainly because breast-conserving surgery (BCS) isn't done as much. Radiation may still be needed after mastectomy if the cancer is larger than 5 cm (2 inches) in size, or if cancer is found in the lymph nodes.

Radiation is also used to treat cancer that has spread, such as to the bones or brain.

When given after surgery, radiation therapy is usually not started until the tissues have been able to heal for about a month. If chemotherapy is to be given as well, radiation therapy is usually delayed until chemotherapy is complete.

External beam radiation

External beam radiation is the usual type of radiation therapy for men with breast cancer. The radiation is focused from a machine outside the body on the area affected by the cancer. This usually includes the chest wall where the breast was removed and, depending on the size and extent of the cancer, may include the underarm area, supraclavicular lymph nodes (nodes above the collarbone) and internal mammary lymph nodes (nodes beneath the breast bone in the center of the chest).

Before your treatments start, the radiation team will take careful measurements to determine the correct angles for aiming the radiation beams and the proper dose of radiation. They will make some ink marks or small tattoos on your skin that they will use as a guide to focus the radiation on the right area. You might want to ask your health care team if these marks will be permanent.

Radiation therapy is much like getting a diagnostic x-ray, but the radiation is more intense. The procedure itself is painless. Each treatment itself lasts only a few minutes, but the setup time − getting you into place for treatment − usually takes longer.

Breast radiation is most often given 5 days a week (Monday thru Friday) for about 6 to 7 weeks. In studies of women with early breast cancer that had not spread to lymph nodes, giving radiation over 3 weeks has been shown to be just as effective as giving it over 5 to 6 weeks. This, known as hypofractionated radiation therapy, has not been studied in men (because breast cancer is so rare in men).

Possible side effects of radiation therapy: The main short-term side effects of radiation therapy are fatigue and sunburn-like skin changes. Your skin may peel. Your health care team may advise you to avoid exposing the treated skin to the sun because it may make the skin changes worse. Most skin changes go away in a few months.

Radiation to the breast/chest can sometimes damage some of the nerves to the arm. This, called brachial plexopathy, can lead to numbness, pain, and weakness in the shoulder, arm, and hand.

Radiation to the axilla (underarm area) can cause abnormal swelling in the arm. This is called lymphedema, and is more common if underarm lymph nodes have been surgically removed. In rare cases, radiation therapy may weaken the ribs, which could lead to a fracture.

In the past, parts of the lungs and heart were more likely to get some radiation, which could lead to long-term damage of these organs in some patients. Modern radiation therapy equipment allows doctors to better focus the radiation beams, so these problems are rare today.

A very rare complication of radiation to the breast is the development of another type of cancer called angiosarcoma. These rare cancers can grow and spread quickly.


Brachytherapy, also known as internal radiation, is another way to deliver radiation therapy. Brachytherapy is rarely used to treat breast cancer in men because it is only used in someone who has had breast conserving surgery (BCS). Instead of aiming radiation beams from outside the body, radioactive seeds or pellets are placed into a device in the breast tissue near the place where the cancer had been. It is often used as a way to add an extra boost of radiation to the tumor site (along with external radiation to the whole breast), although it may also be used by itself (see below). Tumor size, location, and other factors may limit who can get brachytherapy. It is also important to realize that studies of brachytherapy for breast cancer have only included women, so there is no way to know if it would work as well in men.

There are different types of brachytherapy.

Intracavitary brachytherapy: This is the most common way brachytherapy is given to breast cancer patients and is considered a form of accelerated partial breast irradiation. A device is put into the space left from BCS and is left in place until treatment is complete. There are several different devices that can be used: MammoSite®, SAVI®, Axxent®, and Contura®. They all go into the breast as a small catheter (tube). The end of the device inside the breast is then expanded so that it stays securely in the right place for the entire treatment. The other end of the catheter sticks out of the breast.

For each treatment, one or more sources of radiation (often pellets) is placed down through the tube and into the device for a short time and then removed. Treatments are given twice a day for 5 days as an outpatient. After the last treatment, the device is collapsed down again and removed.

Early studies of intracavitary brachytherapy as the only radiation after BCS had promising results, but didn’t directly compare this technique with standard whole breast external beam radiation.

One study comparing long-term outcomes between intracavitary brachytherapy and whole breast radiation after BCS found that women treated with brachytherapy were twice as likely to go on to get a mastectomy of the treated breast (most likely because cancer was found in that breast). The overall risk was still low, however, with about 4% of the women in the brachytherapy group needing mastectomy versus only 2% of the women in the whole breast radiation group.

This study raises questions about whether irradiating only the area around the cancer will reduce the chances of the cancer coming back as much as giving radiation to the whole breast. More studies comparing the 2 approaches are needed to see if brachytherapy should be used instead of whole breast radiation.

Intracavitary brachytherapy can also have side effects, including redness, bruising, breast pain, infection, and a break-down of an area of fat tissue in the breast. As with whole breast radiation, the ribs can weaken and fracture.

Interstitial brachytherapy: In this approach, several small, hollow tubes (catheters) are inserted into the breast around the area where the tumor was removed and are left in place for several days. Radioactive pellets are inserted into the catheters for short periods of time each day and then removed. This method of brachytherapy has been around longer (and has more evidence to support it), but it is not used as much anymore.

For more information about radiation therapy, see the Radiation Therapy section of our website.

The American Cancer Society medical and editorial content team
Our team is made up of doctors and master's-prepared nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Last Medical Review: October 10, 2014 Last Revised: January 26, 2016

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