Patient education: Mouth sores from cancer treatment (The Basics)

Why might I get mouth sores from cancer treatment? — Mouth sores are a common side effect of a cancer treatment called chemotherapy. Chemotherapy is the medical term for medicines that kill cancer cells or stop them from growing.

Not everyone who is treated with chemotherapy will get mouth sores. It depends on the chemotherapy medicines and the doses that you get. When mouth sores happen, they usually start shortly after the chemotherapy starts. They are often worst about 1 week after the chemotherapy starts.

Another cancer treatment, called radiation therapy, can also cause mouth sores. Mouth sores happen only when people are treated with radiation to their head or neck. Mouth sores usually happen within the first 2 to 3 weeks of radiation therapy.

Sometimes, people with cancer get mouth sores that are not related to treatment.

What are the symptoms of mouth sores from cancer treatment? — Mouth sores usually start as red areas or a burning feeling in the mouth. The sores can then become raised white patches and, later, open sores that are often painful. Mouth sores can also cause a sore throat.

Symptoms can be mild or severe. Some people have mouth and throat sores that are very painful. This can cause trouble swallowing and make it too painful to eat or drink.

Can mouth sores be prevented? — To help prevent mouth sores, see your dentist before you start cancer treatment, if possible. They can check your teeth and do any dental work you need.

In some cases, people can lower their chance of getting mouth sores if they chew ice chips right before their chemotherapy.

Doctors are studying other ways to prevent mouth sores. Your doctor might recommend a medicine or procedure, such as laser therapy, before your cancer treatment starts. This is more likely if you are getting a bone marrow transplant, which is a treatment used for some cancers such as leukemia and lymphoma.

What can I do on my own to manage my mouth sores? — To help reduce symptoms and help your mouth sores heal, you can:

●Change your diet – Avoid spicy, salty, or dry foods, or foods with sharp edges (like chips) that could cut your mouth. You should also avoid caffeine and alcohol.

●Keep your mouth clean – Rinse out your mouth with water after you eat.

●Keep your dentures clean – Remove and clean your dentures often.

●Use a soft toothbrush or foam swab (if they don't hurt you) to clean your teeth and gums.

●See your dentist for regular follow-ups.

What other treatments can help? — Your doctor can prescribe other treatments to help with your symptoms. These can include:

●Special mouth rinse or mouthwash – These have medicines in them that can numb and coat the sores.

●Strong pain medicines that you take by mouth

●Medicines to treat an infected mouth sore – Sometimes, mouth sores get infected.

If you can't eat or drink because of your mouth sores, you might need to get fluids or nutrition through a thin tube that goes into your vein, called an "IV."

When will my mouth sores get better? — In most cases, mouth sores from chemotherapy get better within a few days. But they usually come back with the next round of treatment, unless the dose is lowered.

For people getting radiation to the head or neck, the mouth sores usually continue to get a little worse each week until the treatments are done. Then, they get better after a few days to weeks.

When should I call my doctor or nurse? — Call your doctor or nurse if your pain is so severe that you are having trouble eating or drinking.

More on this topic

Patient education: Chemotherapy (The Basics)
Patient education: Radiation therapy (The Basics)
Patient education: Managing pain when you have cancer (The Basics)
Patient education: When your cancer treatment makes you tired (The Basics)
Patient education: Nausea and vomiting with cancer treatment (The Basics)
Patient education: Managing loss of appetite and weight loss with cancer (The Basics)
Patient education: Malnutrition (The Basics)
Patient education: Malnutrition – Discharge instructions (The Basics)
Patient education: Hair loss from cancer treatment (The Basics)
Patient education: Mouth sores (The Basics)