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Mouth sores: Cancer-related causes and how to cope
Understand how to manage cancer treatment side effects, including mouth sores, so you can feel more in control of your body as you go through cancer treatment.
By Mayo Clinic staffIf you're about to begin cancer treatment, be aware that certain treatments can cause mouth sores (oral mucositis). Mouth sores can be painful and distressing. They can range from a mere inconvenience to a severe complication that may make you unable to continue your cancer treatment.
As you begin your cancer treatment, it's important to understand how your treatment can cause mouth sores and what steps you can take to help prevent this complication. If you're already experiencing mouth sores, find out what you and your doctor can do to minimize the pain.
What are cancer-related mouth sores?
Cancer-related mouth sores are sores or ulcers that form on the lining of the inside of your mouth (mucous membranes) or on your lips. The sores appear burn-like and can be painful, making it difficult to eat, talk, swallow and breathe. Sores can appear on any of the soft tissues of your lips or your mouth, including your gums, your tongue, or the roof and floor of your mouth.
How do cancer treatments cause mouth sores?
Chemotherapy and radiation to the head or neck area can both cause mouth sores. That's because these cancer treatments are intended to kill rapidly growing cells — such as cancer cells. Some healthy cells in your body also divide and grow rapidly, including the cells that line the inside of your mouth. Unfortunately these healthy cells are also damaged by chemotherapy and radiation. Damage to the cells in your mouth makes it difficult for your mouth to heal itself and to fend off bacteria, leading to sores and infections.
Bone marrow or stem cell transplants also can lead to mouth sores if you develop graft-versus-host disease (GVHD). In GVHD the transplanted cells or stem cells try to reject your body's normal cells. The transplanted cells view your body's cells as foreign and attack them. Mouth sores are just one sign of GVHD.
Whether or not you experience mouth sores during cancer treatment depends on a number of factors, including your individual treatment. Some people are more likely to develop mouth sores, including:
- Younger people
- People with pre-existing gum disease
- People who don't brush and floss regularly
- People taking certain medications, including certain medications for depression and for pain
People who receive both chemotherapy and head or neck radiation are most likely to experience mouth sores.
Here's what you may experience with each type of cancer treatment.
Chemotherapy
Whether you experience mouth sores while undergoing chemotherapy depends on the type and dose of medication you receive, as well as how often you receive your treatment. The chemotherapy drugs most likely to cause mouth sores include:
- Cytarabine
- Doxorubicin (Adriamycin)
- Etoposide (Etopophos, VePesid)
- Fluorouracil (Adrucil)
- Methotrexate
- Capecitabine (Xeloda)
Mouth sores usually develop a few days after treatment begins and go away 10 to 14 days after treatment ends. Sores may begin as mild pain or burning in your mouth. White patches may form on the gums and soft tissues in your mouth. As the sores grow and lose their covering, they become large red lesions. The mouth sores usually reach their peak around the seventh day after chemotherapy treatment ends. In severe cases, mouth sores can bleed or cause extreme pain that makes it difficult to eat, drink or speak.
Head or neck radiation therapy
Only radiation aimed at your head or neck causes mouth sores. Whether your radiation treatment will cause mouth sores depends on how much radiation you receive and whether you're also receiving chemotherapy at the same time. Mouth sores caused by radiation usually develop later in your treatment and can last longer after treatment ends, compared to mouth sores caused by chemotherapy. You may begin to experience mouth pain two to three weeks after you begin radiation. Patchy lesions may develop in your mouth in the following weeks. More intense doses of radiation will cause mouth sores to develop more quickly. Mouth sores from radiation may last up to six to eight weeks.
Bone marrow or stem cell transplant
Mouth sores associated with GVHD develop two to three weeks after a bone marrow or stem cell transplant. People who receive transplants usually receive high-dose chemotherapy or radiation to prepare their bodies for the transplant. Since these therapies also cause mouth sores, it can be difficult to tell whether the sores are from the transplant preparation treatment or from GVHD. Your doctor may test cells from your mouth to determine what's causing your mouth sores.
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