Breast cancer can be treated in a variety of ways, including with radiation therapy.

Depending on your cancer type and stage, radiation can be used alone as a treatment for breast cancer, or with other therapies.

There are different types and schedules of radiation therapy for breast cancer, and knowing more about it and what to expect can help you prepare for this treatment.

According to the National Cancer Institute, radiation therapy uses high energy rays or particles to kill cancer cells.

Radiation kills or slows the growth of cancer cells. While it also affects nearby healthy cells, the healthy cells typically recover after the course of radiation treatment has ended. Doctors try to protect healthy cells by:

  • using as low a dose of radiation as possible
  • spreading out treatment over time
  • aiming the radiation at a very specific part of your body

The most common type of radiation therapy is external beam radiation, according to the American Cancer Society.

With external beam radiation, a machine directs high energy beams of radiation at the area where the cancer cells have been found.

Radiation therapy can be used in a variety of instances for breast cancer treatment. It can be used:

  • after breast-conserving surgery, to reduce the risk of recurrence in your breast
  • after a mastectomy, particularly if:
    • the tumor was larger than 5 centimeters
    • there was cancer in your lymph nodes
    • the margins were positive
  • to help ease side effects if the cancer spreads to other areas of your body like your bones or brain

Depending on the type of breast cancer and the cancer stage, it can be used with other cancer treatments like surgery and chemotherapy,

There are two main types of radiation therapy: external beam radiation and internal radiation. Some people have both types of treatment.

External beam radiation

According to the National Cancer Institute, external beam radiation is the most common type of radiation therapy for breast cancer.

With this method, a large machine sends beams of radiation to the area of your breast that’s been affected by cancer.

The beams are aimed directly at the site of your tumor. While the machine moves around you, it can send radiation to your tumor from different directions.

Internal radiation

The National Cancer Institute also shares that internal radiation is when a source of radiation is put into your body. This type of radiation is also known as brachytherapy.

In brachytherapy, a device with radioactive seeds or pellets is temporarily put into your breast tissue where the tumor was located. For breast cancer, brachytherapy is often given through one or more small tubes or catheters.

Some factors, such as the tumor location and size, can limit who can get this type of radiation therapy.

Internal radiation typically works well when:

  • breast cancer is at an early stage
  • cancer is just in one spot in your breast
  • you’ve had breast-conserving surgery

Knowing what to expect before radiation therapy can help you better prepare for the treatment and address any concerns you might have ahead of time.

What to expect with external beam radiation

If you have external beam radiation, you’ll meet with your radiation oncologist and a nurse before starting treatment. They will walk you through what to expect with external beam radiation, and the risks and benefits of this treatment.

At this time, you’ll likely have a physical exam and go over your medical history.

Additionally, the radiation oncologist and a radiation therapist will take scans of your treatment area. This will help define the boundaries of the affected area so they know where to aim the radiation beams.

They will put marks (tattoos or ink) on your skin to mark the area. You will need the marks throughout the course of your treatment. The marks will be used to line up your body, so the radiation beams target the exact area that needs to be treated.

Sometimes a body mold will be made to immobilize you during the treatment and to help keep your body still.

Each treatment will only last a few minutes. The session setup will take longer than the actual treatment. You won’t feel anything when the machine is turned on for the treatment. It’s a painless procedure.

What to expect with internal radiation

Before you get any internal radiation, you’ll meet with your radiation oncologist. They will:

  • do a physical exam
  • ask about your medical history
  • go over what your internal radiation treatment will entail

Most internal radiation, or brachytherapy, is given with a catheter. This is a small, flexible tube that’s surgically placed into the space left from breast-conserving surgery.

At the end of the catheter is a device that can be inflated inside your breast so that it stays in place for the duration of the treatment.

During your treatment, radiation pellets or seeds are put down the tube and into the inflatable device. They usually stay there for about 10 to 20 minutes or longer, and then they’re removed. How long the radiation pellets stay in place depends on:

  • your type of cancer
  • your overall health
  • other cancer treatments that you’ve had

Once your course of treatment is over, the catheter and inflatable device will be removed.

With breast cancer, radiation therapy usually begins about 3 to 4 weeks after breast-conserving therapy or a mastectomy, according to the National Breast Cancer Foundation.

External beam radiation is typically given once a day, 5 days a week, for anywhere from 2 to 10 weeks on an outpatient basis. This means you can go home after the treatment.

Sometimes the schedule for external radiation can differ from the standard schedule. Some examples of this include the following:

  • Accelerated fractionation. Treatment is given in larger daily or weekly doses, reducing the duration of the treatment.
  • Hyperfractionation. Smaller doses of radiation are given more than once a day.
  • Hypofractionation. Larger doses of radiation are given once daily (or less often) to reduce the number of treatments.

For brachytherapy (internal radiation), treatments are usually given twice a day for 5 days in a row as outpatient procedures. Your specific treatment schedule will depend on what your oncologist has ordered.

A less common treatment option is to leave the radiation in your body for hours or days. With this type of treatment, you’ll stay in the hospital to protect others from the radiation.

Common side effects of external beam radiation therapy for breast cancer include:

  • sunburn-like skin irritation in the treatment area
  • dry, itchy, tender skin
  • fatigue
  • swelling or heaviness in your breast

Skin changes and changes to your breast tissue usually go away within a few months to a year.

Hair loss from radiation typically occurs only in areas that are radiated. If you have external beam radiation to your breast, you typically won’t lose your hair on your head. You may lose hair in your armpits, depending on the area being radiated.

Long-term effects may also occur with external beam radiation, which may:

  • make your breast become smaller and harder
  • make it more difficult to breastfeed
  • affect reconstruction options
  • impact nerves in your arm

Internal radiation typically has fewer side effects compared to external beam radiation. The most common side effects include:

  • redness or discoloration, and bruising
  • breast pain
  • infection
  • fatty tissue damage
  • fluid collecting in your breast
  • weakness in and fractures of your ribs in rare cases

Many side effects of radiation go away within a few months of your treatment ending. If you have persistent side effects, talk with your doctor.

There are steps you can take to help minimize some of the side effects of radiation therapy.

Radiation for breast cancer is a common treatment that kills or slows the growth of cancer cells. While it also affects nearby healthy cells, these cells usually recover after the treatment has ended.

Radiation therapy can be used alone or with other treatments like surgery and chemotherapy.

Two common types of radiation treatment for breast cancer are external beam radiation and internal beam radiation, also known as brachytherapy, which typically has fewer side effects.

The type of radiation that’s best suited for you depends on:

  • the type and stage of your breast cancer
  • your overall health
  • other cancer treatments you’ve had

Talk with your doctor about your treatment options. Together you can make the treatment decisions that are right for you.