Radiation Therapy Side Effects

Why does radiation therapy cause side effects?

Side effects are common when you’re receiving radiation therapy for cancer. Radiation therapy (radiotherapy) directs powerful energy (usually X-rays) toward tumors, destroying cancer cells. Healthcare providers who specialize in radiation therapy (radiation oncologists) take care to design treatment that delivers maximum damage to cancer cells without exposing healthy cells to radiation.

Still, sometimes the radiation impacts healthy cells near the tumor. Unlike cancer cells, healthy cells can repair themselves after damage from radiation. In the meantime, the damage can cause side effects.

No one can be certain which exact side effects you’ll experience or their severity. Your provider is your best resource for explaining what changes to look for in your body during cancer treatment. But there are general radiation side effects to know about that can help you prepare.

What are common side effects of radiation therapy?

The most common side effect of radiation therapy is fatigue. Mild or moderate fatigue (tiredness that doesn’t improve with rest) affects many people who get radiation therapy.

Other common side effects include:

• Skin changes: Skin at the treatment site may redden (on light skin tones), darken (on dark skin tones), blister, peel or itch (radiation dermatitis). The changes may remind you of a sunburn.
• Hair loss: Radiation therapy can cause hair loss at the treatment site. Radiation to your head (for brain cancer and some head and neck cancers) may lead to hair loss on your scalp.
• Decreased blood cells: Radiation therapy can cause lower blood cell counts.

These side effects are usually short-term and gradually improve after treatment. But they can be long-lasting for some people.

Which parts of your body are most affected?

For the most part, side effects depend on where your healthcare provider sends the radiation. Exposure may cause side effects that impact your:

• Brain.
• Head and neck.
• Chest.
• Breast.
• Stomach and abdomen.
• Pelvis.

Brain

Radiation therapy for brain cancer can impact your central nervous system. Exposure can affect structures that help you think, use your senses and communicate. Side effects may include:

• Nausea.
• Hair loss or thinning hair on your scalp.
• Headaches or pressure inside your head.
• Memory loss, confusion or difficulty concentrating.
• Vision changes (like blurred vision).
• Difficulty hearing (speech may sound muffled).

Stereotactic radiosurgery (SRS), which treats small brain tumors in a few sessions, is associated with fewer side effects than conventional radiotherapy to your entire brain. Conventional radiotherapy involves more treatment sessions spread out over more than one week.

Head and neck

Radiation therapy for head and neck cancers can impact the structures that help you taste, smell, eat and speak. Side effects may include:

• Dry mouth or thickened secretions.
• Hoarseness.
• Dental issues (like an increased risk of cavities).
• Loss of taste or altered taste.
• Loss of smell.
• Mouth and throat sores.
• Difficulty swallowing or speaking.
• Swelling in your face and neck.
• Underactive thyroid gland (hypothyroidism).
• Hair loss or thinning hair on your face.
• Jaw stiffness.

Chest

Radiation therapy for cancers in your chest area, including lung cancer and esophageal cancer, can damage cells in organs that help you swallow and breathe. Side effects may include:

• Sore throat.
• Heartburn.
• Difficulty swallowing.
• Loss of appetite.
• Cough.
• Shortness of breath.

Breast

Radiation therapy for breast cancer can lead to inflammation or fluid build-up in your breast tissue. This may lead to side effects like:

• Breast pain, firmness or tenderness.
• Changes in how your breast looks.
• Stiffness in your shoulder or arm.
• Hair loss in the treatment area.
• Swelling or tightness in your breast, armpit or arm (lymphedema).

Stomach and abdomen

Radiation therapy for cancers in your abdomen, including stomach cancer, pancreatic cancer or liver cancer, can irritate the lining of organs that help you poop and digest food. As a result, you may experience:

• Nausea or vomiting.
• Diarrhea.
• Constipation.
• Abdominal pain.
• Gas and gas pain.
• Loss of appetite.
• Unintentional weight loss.

Pelvis

Radiation therapy for cancers in your pelvis, including rectal cancer, uterine cancer, cervical cancer, vulvar cancer, prostate cancer and testicular cancer, can impact your sex organs. It can also cause side effects that are similar to those associated with radiation therapy to your abdomen.

Side effects that can make trips to the bathroom unpleasant include:

• Peeing more often.
• Burning sensation when you pee.
• Leaking urine or stool, or feeling like you can’t hold it.
• Nausea or vomiting.
• Diarrhea.
• Constipation.
• Hair loss in the treatment area.

Side effects that impact your sexual health include:

• Female infertility and early menopause.
• Vaginal dryness, narrowing, itching or burning.
• Male infertility.
• Erectile dysfunction and painful ejaculation.

When do side effects start?

Radiation therapy side effects usually start within the first few weeks of treatment. You may notice some within the first few days. Sometimes, though, side effects don’t show up until several weeks into radiation therapy or a few weeks after treatment is over.

Many people experience different timelines for these side effects. Radiation therapy side effects typically increase as treatment progresses.

How long do side effects last?

Side effects of radiation therapy typically start to improve the first few weeks after treatment. Common side effects, like fatigue, tend to go away within the first few months afterward. It takes hair about two to three months to grow back after radiotherapy for brain or head and neck cancers.

Sometimes, side effects of radiation therapy may linger and become permanent. Or they don’t appear until weeks, months or even years after radiation ends. Much depends on how strong your dose is and which part of your body is receiving the treatment.

It’s important to talk to your healthcare provider about the risks of long-term side effects based on your diagnosis and the type of radiation therapy you’re getting.

How do I manage radiation therapy side effects?

Many of the steps you can take to manage related chemotherapy side effects also work for managing radiation therapy side effects.

Here are some general tips to keep in mind:

• Allow yourself time to rest. Know that you likely won’t be able to “power through” radiation fatigue. Give yourself some grace and slow down when you need to. Plan activities and light exercise around the times of day when you feel the least exhausted.
• Take extra care of your skin and hair. Apply a sunscreen of SPF of 30 or more when you go outside if you’re getting radiation to your head and neck. Wash your skin and hair with lukewarm water and mild soap, and pat dry. Avoid using skin care products with harsh chemicals.
• Prepare for changes to meals and snacks. To prevent digestion issues, you may need to opt for several smaller meals a day instead of three large ones. You may need to choose blander foods than you’re used to. Working with a dietitian can help you manage planning meals and snacks.
• Prioritize your mental health. Care for your mind by getting enough sleep and trying stress-reduction techniques, like meditation. Working with a psychologist or therapist can help you manage cognitive (thinking) difficulties and process the challenges of living with cancer.
• Plan for potential changes to your sex life and fertility. You may need treatments to help manage the sexual side effects of radiotherapy. Your provider may be able to connect you with resources to help you have a baby after treatment.
• Take medications as needed. Your healthcare provider may recommend medications to relieve radiation side effects. Depending on your side effects, they may prescribe drugs to prevent radiation-related side effects.
• Connect with specialists as needed. Dietitians and mental health specialists may be important additions to your care team during radiation therapy. In addition, you may benefit from palliative care. This type of care can help ease cancer symptoms and treatment side effects.