About Radiation for Breast Cancer

What you should know about radiation therapy for breast cancer, its advantages and disadvantages, and more

You might know that radiation therapy is used to treat cancer. In fact, it’s been used for breast cancer since the turn of the 20^th Century. Even though patients have many available treatment options today, it still plays an important role, helping prevent local recurrences and improve overall survival.

Since the first use of radiation to treat breast cancer, researchers have worked to fine-tune the therapy and develop newer techniques. Their progress has lessened side effects from radiation therapy and made it more effective.

Here, BCRF dives into what radiation for breast cancer involves, why it’s effective, and what you can expect during treatment.

What is radiation for breast cancer and why is it used?

Radiation therapy, also called radiotherapy or irradiation, involves using high-energy particles to kill cancer cells or slow their growth. While typical X-rays deploy low doses of radiation, radiation therapy for breast cancer uses relatively high doses.

Cancer cells, like normal cells, must copy their DNA to grow and divide. Radiation targets and damages cancer cells’ DNA so much that cancer cells can’t repair that damage. That then kills cancer cells or slows their growth. The cells that do manage to grow pass along the damaged DNA to “progeny cells” so they eventually can’t grow or survive, either. Radiation therapy doesn’t just target cancer cells; it causes DNA damage in normal cells too. But, because cancer cells typically grow rapidly, DNA damage affects them more. 

Radiation for breast cancer may be used to treat the disease at any stage. It’s not only used in breast cancer treatment to slow or stop cancer growth, but it can also be used to ease some symptoms or reduce a person’s recurrence risk. Radiation therapy is used after chemotherapy or surgery to ensure that any remaining cancer cells don’t regrow.

Radiation may also be used to prevent cancer growth in areas beyond the breast, such as nearby lymph nodes. Additionally, radiation treatment can be used alone in cases where the cancer is in a location that makes surgery impossible or in cases of inflammatory breast cancer, an aggressive cancer that spreads via the lymph ducts and often does not form a discreet lump. 

Types of radiation therapy for breast cancer treatment

There are two main types of radiation treatment for breast cancer: external beam radiation therapy (EBRT) and internal radiation therapy (brachytherapy). The difference between them is in how they’re delivered.

External beam radiation therapy (EBRT)

This is a non-invasive procedure where radiation is administered from outside the body using a special X-ray machine called a linear accelerator. The machine delivers high-energy rays directly to tumors as it moves around the body without touching the patient. In this way, it can deliver radiation from many angles and can be contoured to the tumor’s shape. EBRT can reduce damage to surrounding healthy tissues or nearby organs, because its beam is focused on a specific area and can deliver higher, more precise doses of radiation. As a result, EBRT may have fewer side effects compared to traditional radiation.

EBRT techniques can also be used across a wider area for what’s known as whole breast irradiation (WBI). WBI may be used on a woman who:

• Has ductal carcinoma in situ (a.k.a. stage 0 breast cancer)
• Has stage 2 or 3 breast cancer following lumpectomy or mastectomy
• Has advanced breast cancer following a mastectomy if the cancer has spread to the lymph nodes
• Needs to relieve symptoms of widespread breast cancer

In addition, researchers have developed several newer techniques for utilizing EBRT in breast cancer treatment:  

• 3-dimensional conformal radiation therapy (3D-CRT) combines imaging, precision-dosing calculations, and computer-assisted treatment planning and delivery. This technique merges the typical CT scan with diagnostic-quality imaging such as MRI and PET scans to obtain a better 3D picture of the tumor. It more precisely targets the tumor.
• Intensity-modulated radiation therapy (IMRT) is an advanced type of radiation therapy that uses multiple smaller but powerful energy beams to kill cancer cells. Importantly, these beams can be customized to match the shape of the breast tumor. Radiation beams move in an arc over the target area using state-of-the-art technology.
• Volumetric modulated arc therapy (VMAT), introduced in 2007, is like IMRT in its use of multiple smaller beams but unlike IMRT the radiation machine rotates around the patient while they are lying down. As the treatment machine rotates, it delivers continuous doses of radiation toward a tumor from many angles with the beam constantly reshaping to carefully adjust the dose that is delivered at each angle. VMAT may be used for oddly shaped tumors or tumors close to vital organs.
• Proton therapy uses a different type of charged particle compared to the others: protons instead of X-ray beams or photons. Like other forms of EBRT, proton therapy delivers the radiation dose directly to the tumor. Unlike other EBRT techniques where the radiation passes through the tumor and continues, proton radiation stops where the tumor stops. As a result, proton therapy may do less damage to healthy tissues and organs. Proton therapy is relatively new and long-term follow-up research is needed to fully assess its advantages.

Internal radiation therapy or brachytherapy is administered internally to a targeted area with higher doses of radiation possible compared to EBRT. If a breast cancer care team decides to use brachytherapy, it typically follows lumpectomy or mastectomy. A sealed radiation delivery device (seeds, ribbons, or capsules) is placed in the body near the tumor site or where breast tissue was removed. Brachytherapy’s localized and precise delivery of high doses of radiation provides several advantages over EBRT; healthy tissues are less affected, treatment time can be reduced, and there may be fewer side effects.

All radiation treatment methods have some disadvantages, including harming nearby healthy cells, requiring multiple days or weeks of treatment, and causing side effects. But modern radiation therapy is more precise, and doctors have tools to reduce its impact on healthy cells.

What to expect during radiation for breast cancer

If you need radiation, you’ll first meet with your radiation therapy team to create a treatment plan that’s tailored to you.

They’ll conduct a CT scan to map the cancer in your breast to figure out what angles and shapes of radiation beams are needed. Medical dosimetrists will also calculate how much radiation you’ll need in each session. During this simulation, technicians may mark your skin to help position the beam during treatment. They may also create a “vac-lock,” which is a special body mold that will keep you steady during each procedure. Additionally, your team might share techniques for holding your breath so that you stay as still as possible during treatment.

Right before you begin treatment, a radiation therapist will position you on a treatment table. Treatment typically lasts between 10 and 40 minutes. Radiation for breast cancer usually requires three to six weeks of daily (Monday through Friday) treatment. Some early breast cancers only need as little as five days.

Short-term side effects of radiation for breast cancer

Radiation therapy may cause some side effects, the most common of which are fatigue, loss of appetite, and skin irritation. Your skin may be more sensitive and appear red, swollen, or warm to the touch like a sunburn. Peeling, itchiness, and blistering may also occur. For most patients, these side effects will completely resolve after treatment.

Additional side effects may occur including arm swelling, breast pain, changes in breast sensations, hair loss, reduced sweat where you were treated, or difficulty moving your shoulder.

Short-term side effects of radiation for breast cancer tend to crop up toward the end of treatment or within a few weeks of finishing it.

Long-term side effects of radiation for breast cancer

Long-term side effects of radiation therapy are possible, vary from person to person and are also dependent on the length of treatment and how much radiation was used. Late- or long-term side effects can appear anywhere from six months to a year after you’ve completed treatment.

You may experience persistent or permanent changes to your skin, such as scarring or differences in color and texture where you received radiation.

Other long-term side effects include:

• Under the skin, soft tissue and muscles may develop scarring and, in some cases, they may shrink or tighten. This could mean a loss of flexibility and movement or even chronic swelling.
• Chronic or recurring skin ulcers.
• Blood vessels under the skin’s surface may widen or become more obvious. Called spider veins or telangiectasias, they are generally not harmful.
• Permanent hair loss at the treatment site or a change in the color and texture of your hair beyond areas that are directly treated.
• The skin in the treated area can become more sensitive to sunlight permanently.

There are ways to ease some of these side effects of radiation therapy. Consult your care team for strategies, especially if you experience worsening or discomfort.  

Other long-term side effects of radiation therapy for breast cancer include a slight increase in a person’s risk of developing heart disease, particularly if the heart cannot be fully excluded from the treatment area (such as if the cancer is in your left breast). Inflammation of the sac surrounding the heart (also called acute pericarditis) is another potential side effect of radiation for breast cancer, but this is not common, as radiation oncologists go to great lengths to protect and avoid the heart during treatment.  

Lymphedema, a painful swelling of the arm or upper body, can be another longer-term side effect of radiation therapy. It occurs when lymphatic fluid does not properly drain following radiation to the lymph nodes under the arm, neck, or torso. Lymphedema is sometimes treated with surgery to unblock the lymph nodes or to transfer new nodes into the affected areas.

In rare cases, rib fractures, chest wall tenderness, inflamed lung tissue, or secondary cancers may develop. While some of these long-term side effects can be severe, the benefits of radiation therapy usually outweigh the disadvantages. Your care team can address any concerns and is a valuable resource.

Research to advance radiation for breast cancer

Researchers, particularly radiation oncologists, are developing strategies to make radiation more effective while reducing side effects that can affect a patient’s quality of life. They have discovered that breast tumors can become resistant to radiation therapy and BCRF investigators are exploring the mechanisms involved. Research shows that radiation can activate the immune system, and investigators are seeking ways to leverage this discovery.

Other BCRF-funded projects are focused on:

• Increasing our understanding of breast cancer tumor biology to make radiation more effective
• Identifying factors that cause a tumor to become resistant to radiation therapy and developing strategies to prevent that process
• Improving how side effects are managed
• Testing radiation therapy in combination with other treatments and drugs to maximize its impact

Radiation is an important treatment for breast cancer and is used in many ways. Through research, we’ll make this therapy even more effective, optimize how it’s used, and improve patient outcomes.