Roughly 70 percent of patients receiving head and neck cancer radiotherapy develop xerostomia (dry mouth), with significant changes in volume, consistency and pH of secreted saliva. This can last from months to years, or permanently depending on the degree of damage.
Our salivary glands (parotid, submandibular and sublingual) are extremely sensitive to radiotherapy (second only to white blood cells) and can be damaged by chemotherapeutic agents as well, causing xerostomia.
Saliva provides a number of benefits including oral hygiene (floats away food debris and contains lysozyme that prevents microbial overgrowth), lubrication and binding (binds food into a slippery bolus to be swallowed without damaging the esophageal mucosa), alkaline buffering, and starch breakdown (through alpha-amylase).
Cancer patients who have compromised salivary glands have a greater incidence of dental caries (tooth decay from acids produced by oral bacteria), and oral infections such as candidosis, mucositis, periodontal disease and osteoradionecrosis; and difficulty chewing and swallowing. They may also have altered taste, which takes the joy out of eating.
This overview of treatment strategies is designed to provide some pointers to assist you in taking good care of patients suffering from dry mouth due to chemotherapy and radiation.
Acupuncture
Radiation causes external dryness, whereas hormonal therapies tend to cause internal dryness. Ying / spring / water points such as LI 2 and ST 44 help stimulate saliva production, and tonifying yin with SP 6 and points on the yangming channel such as ST 36 and LI 4 are also useful. If the issue is chronic, you may want to include K 6 to tonify kidney yin.
Li Peiwen (Management of Cancer With Chinese Medicine, 2003) lists the following as "commonly used" acupoints for the treatment of xerostomia: LU 10, LI 4, KI 6, LU 7, CV 23, GB 20, SJ 17 and PC 4.
Oral Rinses and Lozenges
"Swishing" with a mix of 1 tsp of Himalayan salt and 1 tsp of baking soda in 8 ounces of distilled water can provide temporary relief. Some experts recommend adding peppermint or other essential oils to the mix. Slippery elm, marshmallow and licorice roots can be made into a tea that helps to coat the mouth and throat, although meta-analyses state there's insufficient evidence to recommend.
The National Cancer Institute (NCI) recommends avoiding alcohol-based mouthwashes (because they can make matters worse by drying the mucosa) and suggests using products such as biotene spray or lozenges in their place. The NCI advises patients to chew xylitol gum or suck on tart fruit candy, fruit popsicles, lemon sorbet, and citrus fruits, and to keep well-hydrated.
Patients have reported to me that xylitol mints make them cough and that hot showers in the morning improve dry mouth by breathing the moist air. They also report that high fluoride toothpastes stimulate salivary glands. ("Synthetic or artificial" saliva has been developed, but patient satisfaction has generally been low.)
Holding 2-3 tablespoons of coconut or sesame seed oil in the mouth for 10-plus minutes also can provide relief and discourage bacterial overgrowth.
Supplements
Curcumin is a powerful antioxidant and anti-inflammatory that can improve inflamed glands, and reduce the incidence of lichen planus and mucositis. Alpha-hydroxy acids and malic acid have been studied and shown to improve xerostomia symptoms.
American ginseng has been anecdotally known to reduce symptoms, but currently there are no randomized, controlled trials on its effect.
Preventive Strategies
If your patient has been diagnosed with head or neck cancer, there are a number of recommendations you can make to limit the symptoms and repercussions of xerostomia:
- On the top of the list is maintaining proper oral health before the treatment begins and quitting smoking if a current smoker.
- Addressing any cavities, broken or cracked teeth, loose crowns or fillings, or gum disease is also important because infections can develop when your patient's immune system is compromised. The NCI recommends the patient's dentist be part of the cancer care team.
- The patient should avoid medications that interfere with salivary gland function such as antihistamines, antihypertensives, hormones and bronchodilators. According to Wolff, et al., 56 medications have strong evidence of causing salivary hypofunction.
Author's Note: Chinese herbal remedies are too involved to be addressed in this overview.
Resources
- Salivary Glands and Saliva: www.vivo.colostate.edu/hbooks/pathphys/digestion/pregastric/salivary.html.
- Jensen SB, et al. A systematic review of salivary gland hypofunction and xerostomia induced by cancer therapies: management strategies and economic impact. Support Care Cancer, 2010;18:1061-79.
- Kho HS. Understanding of xerostomia and strategies for the development of artificial saliva. Chin J Dent Res, 2014;17:75–83.
- Lalla RV, et al. Oral Complications of Cancer Therapy. In: Yagiela JA, et al., eds.: Pharmacology and Therapeutics for Dentistry. 6th Edition. St. Louis, MO: Mosby Elsevier, 2011, pp. 782-98.
- Lee TK, et al. Effect of North American ginseng on 137Cs-induced micronuclei in human lymphocytes: a comparison with WR-1065. Phytother Res, 2008;22(12):1614-1622.
- Myers RA, Marx RE. Use of hyperbaric oxygen in postradiation head and neck surgery. NCI Monogr, 1990;(9):151-7.
- Samarth RM, et al. Utilization of cytogenetic biomarkers as tool for assessment of radiation injury and evaluation of radiomodulatory effects of various medicinal plants – a review. Drug Des Devel Ther, 2015;9:5355–5372.
- Wolff A, et al. A guide to medications inducing salivary gland dysfunction, xerostomia, and subjective sialorrhea: a systematic review sponsored by the World Workshop on Oral Medicine VI. Drugs in R&D, 2017;17(1):1-28.
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