A Phase III placebo-controlled trial of oral pilocarpine in patients undergoing radiotherapy for head-and-neck cancer

Abstract

Purpose: To test the hypothesis that the use of oral pilocarpine during and after radiotherapy (RT) for head-and-neck cancer would reduce the symptoms of post-RT xerostomia.

Methods and materials: One hundred thirty patients were randomized in a double-blind method to receive either pilocarpine (5-mg tablets) or placebo three times daily starting on Day 1 of RT and continuing for 1 month after treatment. The eligibility criteria included a planned dose of >50 Gy as radical or postoperative RT for head-and-neck cancer, with at least 50% of both parotid glands included in the treatment fields. The primary outcome measure was the severity of xerostomia as assessed by a patient-completed linear analog scale 3 months after RT. Secondary outcome measures included quality of life during therapy (as assessed by the McMaster University Head-and-Neck Questionnaire) and severity of mucositis during RT (as assessed using Radiation Therapy Oncology Group scales).

Results: No difference was observed between the pilocarpine-treated patients and the placebo group in the severity of xerostomia score as assessed by linear analog scale at baseline and 1, 3, and 6 months after treatment (repeated measures analysis, p = 0.92). No difference was apparent in the severity of mucositis during RT; 56.3% of patients receiving pilocarpine had Grade III/IV mucositis compared with 50.8% treated with placebo. No difference in quality of life was noted between the treatment groups during or after RT. The questionnaire score at 3 months after RT was 5.0 (SD 1.0). in the pilocarpine group and 4.9 (SD 0.9) in the placebo group.

Conclusion: We were unable to detect a beneficial effect of pilocarpine on RT-induced xerostomia when administered during RT for head-and-neck cancer.