Radiation Therapy for Breast Cancer in Men


Radiation therapy is treatment with high-energy rays (such as x-rays) or particles that destroy cancer cells. The most common type of radiation therapy for men with breast cancer is called external beam radiation. A machine focuses the radiation on the area affected by the cancer.

When might radiation therapy be used?

Not all men with breast cancer need radiation therapy, but it may be used in several situations:

  • After breast-conserving surgery (BCS), to help lower the chance that the cancer will come back in the remaining breast tissue or nearby lymph nodes. Radiation 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.
  • After a mastectomy, especially if the cancer is larger than 5 cm (about 2 inches), attached to the skin, or if cancer is found in the lymph nodes.
  • If cancer has spread to other parts of the body, such as the bones or brain.

Which areas need radiation depends on whether you had a mastectomy or breast-conserving surgery (BCS) and whether or not the cancer has reached nearby lymph nodes.

  • If you had a mastectomy and no lymph nodes had cancer, radiation is focused on the chest wall, the mastectomy scar, and anywhere drains had been placed after surgery.
  • If you had BCS, you will most likely have radiation to the entire breast (called whole breast radiation), and an extra boost of radiation to the area in the breast where the cancer was removed (called the tumor bed) to help prevent it from coming back in that area. The boost is often given after the treatments to the whole breast have ended. It uses the same machine, with lower amounts of radiation, but the beams are aimed at the tumor bed.
  • If cancer was found in the lymph nodes under the arm (axillary lymph nodes), this area may be given radiation, as well. In some cases, the area treated might also include the nodes above the collarbone (supraclavicular lymph nodes) and the nodes beneath the breast bone in the center of the chest (internal mammary lymph nodes).

When will I get radiation therapy?

If you will need external radiation therapy after surgery, it is usually not started until your surgery site has healed, which is often a month or longer. If you are getting chemotherapy as well, radiation treatments are usually delayed until chemotherapy is complete.


Preparing for external beam radiation therapy

Before your treatment starts, the radiation team will carefully figure out 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 to focus the radiation on the right area. Check with your health care team whether the marks they use will be permanent.


Possible side effects of radiation therapy


  • Swelling in the breast or chest wall
  • Fatigue

Your health care team may advise you to avoid exposing the treated skin to the sun because it could make the skin changes worse. Most skin changes get better within a few months. Changes to the breast tissue usually go away in 6 to 12 months, but it can take longer.

External beam radiation therapy can also cause side effects later on:

  • Radiation to the breast or chest wall can sometimes damage some of the nerves to the arm. This is called brachial plexopathy and can lead to numbness, pain, and weakness in the shoulder, arm, and hand.
  • Radiation to the underarm lymph nodes can cause lymphedema, a type of pain and swelling in the arm or chest.
  • 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 women. 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 or chest wall is the development of another cancer called an angiosarcoma.

More information about radiation therapy



The American Cancer Society medical and editorial content team


Jardell P, Vignot S, Cutuli B, et al. Should Adjuvant Radiation Therapy Be Systematically Proposed for Male Breast Cancer? A Systematic Review. Anticancer Research. 2018 (38): 23-31.

Khan A and Haffty BG. Chapter 42: Postmastectomy Radiation Therapy. In:  Harris JR, Lippman ME, Morrow M, Osborne CK, eds. Diseases of the Breast. 5th ed. Philadelphia: Wolters Kluwer Health; 2014.



National Comprehensive Cancer Network (NCCN). Practice Guidelines in Oncology: Breast Cancer. Version 3.2017. Accessed at www.nccn.org on January 18 2018.

Whelan T, MacKenzie R, Julian J, et al. Randomized trial of breast irradiation schedules after lumpectomy for women with lymph node-negative breast cancer. J Natl Cancer Inst. 2002;94:1143–1150.


