Treating recurrence of parotid benign pleomorphic adenomas.

Treatment for recurrence after surgical removal of parotid benign pleomorphic adenoma (PBPA) has not been well defined and is often followed by further recurrence. Surgery is overwhelmingly the most common approach. The risk of facial nerve injury is greater at reoperation since the nerve is less well defined. The value of radiation therapy (RT) has not been determined and incurs with it the risk of possible late occurrence of malignancy or nerve damage. The charts of patients with recurrent PBPA treated consecutively by a single surgeon from 1965 to 1993 were reviewed. All patients had a histopathologically verified diagnosis of PBPA both at the time of primary and subsequent surgeries. Follow-up was obtained from clinical charts and correspondence communication. Recurrence curves were generated using the Kaplan-Meier method. Thirty-nine patients with recurrent PBPA (36 referred and 3 treated primarily at Mayo) were evaluated. The patients were classified according to the type of surgery: 14 patients had previously undergone some form of parotidectomy or had only resection of the tumor for recurrence, and 25 patients underwent parotidectomy since this had not been performed primarily. The mean age in the two groups was 49 and 50 years respectively. The mean follow-up was 10 years after the recurrence treatment. The mean time between initial resection and recurrence in the two groups was 14 and 15 years. The mean time between the recurrence treatment and a second recurrence was 7.5 years. Nine patients had RT in addition to the local resection. Of this group 3 patients (33%) developed another recurrence. Five patients had local resection only, and of this group 1 patient (20%) developed another recurrence. Of the group that had superficial parotidectomy, 3 patients had additional RT and one of these patients (33%) developed another recurrence. Twenty-two patients had superficial parotidectomy only, and of this group 3 patients (14%) developed another recurrence. Only 2 of the 39 patients had complications. One patient developed Frey's syndrome after superficial parotidectomy and 1 patient developed facial paralysis after RT. As in other series, the number of patients is inadequate to allow for firm conclusions. However, it appears that when previous parotidectomy has been performed, simple excision with a margin of surrounding tissue would seem appropriate. Parotidectomy should be carried out if not performed previously. In simple excision after previous parotidectomy, there is a greater risk to the facial nerve because of difficulty in distinguishing the facial nerve from surrounding scar tissue. Our preference is to use general anesthesia so that branches of the nerve are not paralyzed and stimulation of the nerve aids in safe dissection. The value of RT is still indeterminate.