Salivary scintigraphy for assessing the protective effect of pilocarpine in head and neck irradiated tumours

Patients with head and neck cancers can develop salivary hypofunction after radiotherapy. The use of pilocarpine during radiotherapy treatment has bee n shown to be an effective treatment, although its usefulness is being disc ussed. The aim of this study was: (1) to determine the value of a semiquant itative scintigraphy method for measuring the uptake and excretory salivary function of patients with head and neck irradiated tumours; and (2) to stu dy the usefulness of pilocarpine as a salivary gland protector during radio therapy. We prospectively studied 49 patients (mean age 61 years, range 29- 87 years) with head and neck cancer in need of radiotherapy. Patients were divided into two groups consecutively: group P (26 patients) received 5 mg of pilocarpine three times per day starting the day before radiation therap y, and group NP (23 patients) received radiotherapy without pilocarpine and were used as the control group. Salivary gland scintigraphy and a visual a nalogue scale (VAS) of mouth dryness were obtained from each patient before radiotherapy and during the first year after treatment. The most frequent finding after radiotherapy was a quick impairment in parotid and submaxilla ry excretion (P<0.001). There were no statistical differences comparing the pilocarpine group against the non-pilocarpine group. Parotid and submaxill ary uptake significantly decreased after radiotherapy in both groups (P<0.0 01). However, a tendency to recover within the pilocarpine group was observ ed in both the parotids and the submaxillary glands at 12 months. No differ ences were found comparing the VAS results in both groups. Strikingly, VAS data did not correlate with salivary gland dysfunction observed by means of scintigraphy. In conclusion, salivary scintigraphy is a useful technique t o evaluate objectively the salivary gland function of patients with head an d neck irradiated tumours as well as to test the response to pilocarpine. H owever, despite better results on the salivary uptake at 12 months, pilocar pine did not significantly improve salivary gland function. ((C) 2001 Lippi ncott Williams & Wilkins).