Symptomatic treatment of radiation-induced xerostomia in head and neck cancer patients

Question: Are effective interventions possible for symptomatic xerostomia following conventionally fractionated radical radiotherapy for head and neck cancer? Perspective: The practice guideline was initially prepared by two members of the Hamilton Regional Cancer Centre's Head and Neck Cancer Disease Site Group. The report was reviewed, modified, and approved by the Provincial Head and Neck Cancer Disease Site Group, which comprises medical and radiation oncologists, surgeons, and epidemiologists. Community representatives did not participate in the development of this guideline, but will in future reports. Outcomes: The primary outcome of interest was improvement in patient symptomatology. Toxicity was also considered. Results: Quality of Evidence: Evidence was obtained from 4 randomised, placebo-controlled trials in which patients were treated with oral pilocarpine following radical radiotherapy. These trials involved a total of 401 patients with evidence of pre-existing salivary function. Benefits: Pilocarpine, at doses of 5 mg to 10 mg orally three times per day, produced subjective responses including improvements in overall xerostomia symptoms (risk ratio of improvement [RR]: 1.83; 95% confidence interval (CI): 1.34-2.49; p = 0.00013), oral dryness (RR: 1.60; 95% CI: 1.17-2.19; p = 0.0035), and the need for salivary substitutes (RR: 2.51; 95% CI: 1.51-4.15; p = 0.00035). Harms: Adverse parasympathetic events which were related to dosage were reported by participants in randomised controlled trials. The most frequent and troublesome was increased sweating which occurred in about one-quarter of patients taking 5 mg three times per day and about one-half of patients taking 10 mg. Eighteen percent of patients discontinued treatment because of adverse effects during a 36-month maintenance study. None of the events reported in any of these studies were classified as severe or life threatening.