Dry Mouth--One Woman's Story
At 42 years old, Nancy Howe was an enthusiastic body builder. She regularly leg-pressed 500 pounds while grunting loudly. She eventually noticed a persistent, mild sore throat. “I just assumed I'd been grunting too much,” she says. One morning she examined her throat and her knees buckled. “A golfball-sized tumor was bulging from my right tonsil. I was shocked I'd never noticed it before.”
After a whirlwind of medical exams, she underwent a radical tonsillectomy, which removed half of the roof of her mouth, and a temporary tracheotomy, which created an opening in her neck for her to breathe. She proceeded with 7 1/2 weeks of radiation therapy to destroy any remaining cancerous cells. “The hard part wasn't so much the surgeries and radiation but the long-term side effects I wasn't prepared for, mainly dry mouth,” says Howe.
What Causes Dry Mouth?
Xerostomia means dryness of the mouth. It stems from problems with the salivary glands, which produce saliva. People with cancer who receive chemotherapy, radiation, or surgery can have dry mouth if the salivary glands are damaged.
If a salivary gland is removed with surgery, the remaining salivary glands can still produce some saliva. But if the surgery is followed by radiation that targets and destroys the entire area of salivary glands, dry mouth can become permanent. According to the American Dental Association, about 40,000 people annually who are exposed to radiation for head and neck cancer have irreversible salivary gland damage.
According to Athena Papas, DMD, PhD, from the Tufts University School of Dental Medicine and member of the Tumor Board at New England Medical Center, applying radiation levels over 5000 rads to areas containing the salivary glands usually causes permanent loss of saliva. A rad, or radiation absorbed dose, is the amount of radiation that the target area (the salivary glands in this case) absorbs per unit mass of matter.
Why We Need Saliva and What Happens Without It
Saliva lubricates and moistens the mouth. It is essential for chewing, tasting, swallowing, and talking. Enzymes in saliva help digest food. Saliva also protects teeth and gums from decay by neutralizing acids that may form with plaque and helping to wash away food debris and bacteria.
Without the protective benefits of saliva, the teeth are placed at great risk for tooth decay. The saliva not only neutralizes acids in the mouth but in the esophagus, the tube connecting the mouth and throat to the stomach. Studies show that people with radiation-induced dry mouth have more irritation of the esophagus, because they cannot clear the natural build-up of acid without saliva.
People who have lost their salivary glands may develop mouth infections like candidiasis (thrush), have a hard time swallowing food, and have widespread dental disease.
Precautions to Take Before Radiation
A person scheduled to undergo radiation of the head and neck should have a thorough mouth evaluation prior to radiation treatment. Rosemary Costello, RN, Clinical Research Nurse in the Head & Neck Unit at Dana Farber Cancer Institute, recommends patients to see a dentist immediately, either their own or from hospital staff, and complete any dental work needed before radiation starts. Any fragile teeth should be removed before radiation, because removing them afterwards may result in osteoradionecrosis, a destruction of bone tissue caused by radiation. Other pre-existing untreated infections, such as gum disease and cavities, can worsen with radiation.
Paul Marischen, DDS, a prosthodontist, cautions, “Patients who start radiation with untreated mouth problems are at risk for needing dental surgery later when there is an even greater risk of infection and slow wound healing.” A prosthodontist is a type of dentist who restores natural functions of the mouth and teeth or replaces missing teeth.
If patients have metal fillings, they may want their dentist to make mouthguards, which are worn during radiation to prevent “radiation scatter” and injury to the mouth that can occur.
The patient should also be fitted with mouth trays for daily fluoride treatments, needed during and after radiation. Fluoride makes tooth enamel, or the outer covering, more resistant to bacteria. Costello encourages her patients to wear fluoride trays every day for five minutes in the morning and again at night. “Some patients just brush on the fluoride, but it doesn't work as well. The teeth need to be immersed,” she says.
Other recommendations for patients are to use a humidifier at home to moisten the air, stop smoking, avoid alcohol, and, if possible, substitute any medications that cause dry mouth.
Howe strongly advises people to be proactive in their care and seek rehabilitation options early on. “Find a dentist or prosthodontist experienced with radiation patients, get mouthguards, know what your dental insurance will cover, etc.,” she says. Howe regrets not foreseeing the difficulties that lay ahead of her, mainly due to a lack of communication with her doctors. “Sure they said I might have a lack of saliva, but I didn't understand how that would change my life completely. Three years later, a prosthodontist delivers all my mouth care because a regular dentist still can't handle my tooth problems.”
Treatment for Loss of Saliva
There are numerous products to help dry mouth, including saliva stimulants, artificial saliva and other lubricants, and special mouthwashes, toothpastes, and gum.
Pilocarpine tablets, or Salagen®, is a saliva stimulant commonly used to treat dry mouth and throat. It is available by prescription and not appropriate for people with severe asthma or narrow-angle glaucoma. Costello reports that it is an effective drug but has its downsides. “The main side effect is heavy sweating, it is expensive, and because it does not remain in the bloodstream for very long, patients need to be compliant with the recommended dose, which is usually three times daily. Patients may not see results until 8-10 weeks of use.”
Howe found artificial saliva products ineffective. “Plain water worked better for me,” she reports. Papas says, “A tell-tale sign of someone with severe dry mouth is a water bottle nearby.” But she cautions that too much water can actually worsen the situation. “Many radiation patients have at least a little saliva left, so it's important to drink enough water to produce it, but more than that could dilute out the little there is.” Some inexpensive treatments are Adolf's Meat Tenderizer® and vitamin E capsules. The meat tenderizer contains a papaya enzyme, which helps break down thick mucous that can build up from a lack of saliva. Costello instructs her patients to mix one-quarter teaspoon of the tenderizer into eight ounces water, and then gargle with it. For moistening and lubricating the mouth, Papas recommends vitamin E capsules that are broken into the mouth. She believes they work as well as commercially prepared lubricants, such as Oral Balance®.
The Challenge of Eating
When eating, saliva is needed to mix with food to form a ball that can be swallowed. Without it, food simply breaks into pieces that are hard for the esophagus to pass into the stomach.
Howe describes her difficulty with eating, “I ate like a dog, chewing a bit and swallowing clumps of food. I'd sip water but it didn't help the food stick together; instead I had a mouth full of water with things floating in it.” Stray “clumps” of food often traveled into and out her nose.
Howe found soft foods and liquids the easiest to swallow, such as oatmeal, soups, hard-boiled eggs, cottage cheese, yogurt, and ice cream. Her core diet was three blenderized protein shakes daily, with fresh fruit, pudding, or yogurt added in. “Soups were nourishing but risky if they contained anything that needed chewing. Pureed or cream soups were fine,” she says. Howe also added liberal amounts of gravy and liquids to food.
Costello recommends avoiding beverages with caffeine or alcohol, which can dry the mouth further. She adds that spicy, acidic foods like tomato sauce or orange juice, or excessively salty foods may sting the mouth. Papas also encourages patients to avoid high-sugar foods and liquids, as their teeth are at increased risk for cavities.
Mouth Care After Radiation
Papas sees her post-radiation patients every 3 months, mainly to encourage them to persist with their mouth care. “Two to three years down the line, the compliance rate drops to about 30 percent. We're looking for new ways that patients can apply fluoride without the mouth trays,” she says. “But prescription fluoride treatments are needed every day for the rest of their lives.”
Papas recommends Prevident 5000® toothpaste (available by prescription) for people who find it hard to use mouth trays daily. “Prevident is a supplemental fluoride to be brushed on once daily that is designed for people at high risk. Post-radiation patients are at highest risk.” She also recommends calcium-phosphate mouthwash twice daily, which helps strengthen the teeth. These products are used in addition to brushing with regular fluoride toothpaste after meals and daily flossing.
Biotene offers mild products for sensitive teeth and gums, available at most drugstores. The Biotene line includes toothpaste, alcohol-free mouthwash, and gum. Papas recommends them during radiation treatments because they are gentle and blander than regular products. But, she says after radiation people should still include prescription fluoride and calcium-phosphate treatments as part of their daily mouth care.
Emerging Treatments
Evoxac® is a drug approved to treat Sjogren's syndrome, an autoimmune disease causing dry mouth. Now it is being tested through clinical trials for radiation patients. Costello reports that Evoxac may cause less sweating and require fewer pills than pilocarpine, although the trials need to confirm that. Papas adds, “Evoxac's effects as a salivary stimulant may last longer than pilocarpine and might cause less sweating, but it could promote more gastrointestinal upset.”
Another therapy in early stages of research is using gene therapy to restore salivary glands. Only specific cells in the salivary glands are damaged by radiation. But the remaining, undamaged cells normally do not secrete saliva. Scientists are hoping that inserting genes into the non-secreting cells will transform the cells so that they can produce saliva. So far, gene-transfer testing is only performed in animals.
Healing Through Sharing
Howe spoke frankly about her cancer experience in a booklet she published last year titled “Canswer.” “I wrote it because of the lack of pamphlets with practical advice.” After radiation, Howe faced numerous problems that affected her eating. “For two years, I couldn't enjoy restaurants because I couldn't eat solid food. I had pain chewing anything, even soggy cornflakes, because of tooth decay and receding gums.”
Howe realized early on that some advice she received worked, and some didn't. For her, artificial saliva didn't work but water did. “After cancer, there is a lot of gray and very few absolute rules to go by. I used the advice that worked, and what didn't work I let roll off me.”
Howe encourages cancer survivors to share their experiences -- both failures and successes. “Healing comes from allowing yourself to talk about it,” she says. “The best thing that happened to me resulted from my complaining about the pain in my teeth. Someone suggested I go see a prosthodontist, and I've been pain-free ever since.”
Improving Communication Among Health Care Providers and Patients
Papas admits, “Most dentists don't know how to handle radiation patients even though they think they do.” A 1990 conference sponsored by the National Institutes of Health, titled “Oral Complications of Cancer Therapies: Diagnosis, Prevention, and Treatment,” shed light on the potentially severe, long-term oral health problems from chemotherapy and radiation. The disconnect between the oncology team and dentists was soon evident.
In response to the conference, the National Institute of Dental and Craniofacial Research (NIDCR) launched an awareness campaign in 1999 to improve communication among radiation oncologists, oral health professionals, and patients. The campaign provides free educational materials for patients and members of the oncology and oral health care team. They may be ordered by phone through the National Oral Health Information Clearinghouse (NOHIC) at 1-877-216-1019, or obtained directly from the NOHIC web site.
Patricia Sheridan, Director of NOHIC, reports that over 550,000 pieces of educational material have gone out since the start of the campaign. Partnered with other organizations such as the National Cancer Institute, the National Institute of Nursing Research, and the Centers for Disease Control and Prevention, NIDCR hopes to expand awareness of this crucial topic. “Everyone -- the oncology team, the dentist, and the patient -- needs to cooperate for this to work,” says Sheridan.
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