Delayed damage after radiation therapy for head and neck cancer

Abstract

I investigated radiation damage, including osteoradionecrosis, arising from tooth extraction in fields that had received radiation therapy for head and neck cancer, and evaluated the effectiveness of pilocarpine for xerostomia.Between January 1990 and April 1996, I examined 30 patients for bone changes after tooth extraction in fields irradiated at the Department of Oral Radiology, Osaka Dental University Hospital.Nineteen of the patients had been treated for nasopharyngeal cancer and 11 for oropharyngeal cancer.Between January and April 1996, 4 additional patients were given pilocarpine hydrochloride(3-mg, 6-mg and 9-mg of KSS-694 orally three times a day)for 12 weeks and evaluated every 4 weeks as a base line.One had been treated for nasopharyngeal carcinoma, two for cancer of the cheek and one for an unknown carcinoma.Eighteen of the patients(11 with nasopharyngeal carcinoma and 7 with oropharyngeal carcinoma)had extractions.Use of preoperative and postoperative radiographs indicated that damage to the bone following tooth extraction after radiation exposure was related to whether antibiotics were administered the day before the extraction, whether forceps or elevators were used, and whether the tooth was in the field of radiation.Xerostomia improved in all 4 of the patients who received 6-mg or 9-mg of pilocarpine.It improved saliva production and relieved the symptoms of xerostomia after radiation therapy for head and neck cancer, although there were minor side effects such as fever.This information can be used to improve the oral environment of patients who have received radiation therapy for head and neck cancer, and to better understand their oral environment.