By Dena McDowell, MS, RD

People undergoing cancer treatment often suffer from oral mucositis, more commonly known as mouth sores. The pain from these sores is similar to the pain of burning one's mouth on hot food or a hot beverage. These sores make eating, drinking, swallowing, and talking difficult. They can develop on the lips, gums, tongue, roof or floor of the mouth, or in the throat.

What causes mouth sores?

Mouth sores may be caused by:

• Chemotherapy agents
• Radiation therapy
• Stem cell transplants
• Bone marrow transplants.

These therapies stop cell growth to prevent the cancer cells from spreading. Unfortunately, healthy cells are also damaged during this process, which makes it difficult for the mouth to heal and fight bacteria. This situation leads to the development of mouth sores and potential infections.

People with preexisting dental problems or those who do not take care of their teeth are more susceptible to mouth sores. Cancer patients who are undergoing concurrent treatment of both chemotherapy (specifically cytarabine, doxorubicin, etoposide, 5-FU, methotrexate, and Xeloda) and radiation therapy are also highly likely to develop mouth sores.

Duration and severity of mouth sores

The duration and severity of mouth sores depends on the:

• Type of cancer treatment
• Patient's immune status
• Patient's dental hygiene habits.

Chemotherapy-induced mouth sores usually present quickly after the start of treatment and subside within 2 weeks of the therapy's completion. In comparison, radiation-induced mouth sores usually present 2 to 3 weeks into treatment and last much longer (4 to 6 weeks) after treatment ends.

Mouth sores caused by concurrent chemotherapy and radiation therapy are usually the most severe and last for quite a while after treatment. They are also associated with other problems, such as lack of taste and dry mouth, and may persist for up to 2 months after treatment is complete.

Dietary strategies that provide relief

Drink enough fluids to keep the lining of the mouth and throat moist. Follow a bland, soft diet and avoid spicy and acidic foods (citrus, tomato-based products, and vinegar). Choose ripe fruits, cheeses, pasta with cream sauces, meats with gravies, and potatoes. Try eating smaller more frequent meals, and cut food into small bites to lessen the amount of chewing. Because hot or cold foods may be especially painful, try eating them at room temperature.

The importance of prevention of mouth sores

To minimize the severity of mouth sores, see your dentist prior to starting any cancer treatment. Practicing good oral hygiene is extremely important.

• Brush and rinse after each meal to reduce bacterial build-up in the mouth

• If brushing is painful, use foam dental swabs, which are softer than toothbrushes
• Avoid alcohol-based mouth washes; instead, use alcohol-free commercial rinses or salt water rinses to clear the mouth of bacteria and saliva build-up.

If mouth sores cause intense pain, topical pain killer agents are available. There are also mouth rinses that coat the inside of the mouth and throat, numb the area, making it easier to chew and swallow foods. Glutamine powder is also recommended in a swish and swallow technique. See Glutamine article for more information.