Xerostomia as a Complication of Cancer Treatment

Cancer is a devastating, life-altering disease. As our technologyand knowledge base for the treatment of carcinomas expand, however,more and more patients' lives are being spared or prolonged. Unfortunately,the quality of life for many of these patients is diminished--oftendue to side effects associated with necessary cancer treatments.

One such consequence of therapy that cancer patients commonlyexperience is dry mouth, or xerostomia, resulting from irradiationdamage to the salivary glands. Xerostomia is almost always painful;is associated with difficulty in speaking, swallowing, chewing,and sleeping; contributes to severe dental disease and oral infections;and is usually permanent. Clearly, xerostomia is a chronic disabilityfor many patients, with physiological as well as psychologicalcomponents--both of which can greatly influence the patient'swell-being and must be considered in patient management.

Most clinicians agree that relief of xerostomia has been difficultto achieve in most patients with currently available treatmentmodalities. However, the naturally occurring alkaloid pilocarpinehas shown great promise as a therapeutic agent for xerostomia.In the articles featured in this supplement, xerostomia and itsconsequences for patients are discussed, along with the treatmentof xerostomia with drugs such as pilocarpine. The articles byDr. Greenspan and Mr. Iwamoto review the diagnosis and managementof xerostomia, reminding us that subjective discomfort is justone of the problems that these patients face. We also need tobe concerned about infection and caries, both of which may contributeto long-term morbidity in these patients.

Dr. Greenspan also describes the findings from several clinicaltrials evaluating the efficacy of oral pilocarpine hydrochloridetreatment of xerostomia, including two well-controlled, multicenter,prospective, clinical trials--one a fixed-dose trial, the othera dose-titration trial. In both of these pivotal trials, a clinicallysignificant improvement in dryness was noted in patients treatedwith oral pilocarpine hydrochloride. Whole and parotid salivaryflow rates improved as well. The majority of these patients electedto continue oral pilocarpine hydrochloride treatment at studies'end via a maintenance trial.

My article summarizes the results of this maintenance study, whichconfirmed the findings of the two previous studies--namely, thatdryness improves with pilocarpine hydrochloride therapy. In allthe clinical trials reviewed in this supplement, side effectsassociated with this drug were found to be mild and tolerable,with sweating being the most common. In addition, side effectsusually diminished within hours following cessation of therapy.

In summary, the development of pilocarpine hydrochloride tabletsconstitutes an important therapeutic advance in the battle againstxerostomia. Perhaps one of the most compelling reasons for presentingthese data and perceptions, and for continuing with our investigations,is that it is imperative that we establish a standard of carefor patients with xerostomia, such as those suffering from radiation-induceddry mouth.