TREATING RECURRENCE OF PAROTID BENIGN PLEOMORPHIC ADENOMAS

Treatment for recurrence after surgical removal of parotid benign pleo morphic adenoma (PBPA) has not been well defined and is often followed by further recurrence. Surgery is overwhelmingly the most common appr oach. The risk of facial nerve injury is greater at reoperation since the nerve is less well defined. The value of radiation therapy (RT) ha s not been determined and incurs with it the risk of possible late occ urrence of malignancy or nerve damage. The charts of patients with rec urrent PBPA treated consecutively by a single surgeon from 1965 to 199 3 were reviewed. All patients had a histopathologically verified diagn osis of PBPA both at the time of primary and subsequent surgeries. Fol low-up was obtained from clinical charts and correspondence communicat ion. Recurrence curves were generated using the Kaplan-Meier method. T hirty-nine patients with recurrent PBPA (36 referred and 3 treated pri marily at Mayo) were evaluated. The patients were classified according to the type of surgery: 14 patients had previously undergone some for m of parotidectomy or had only resection of the tumor for recurrence, and 25 patients underwent parotidectomy since this had not been perfor med primarily. The mean age in the two groups was 49 and 50 years resp ectively. The mean follow-up was 10 years after the recurrence treatme nt. The mean time between initial resection and recurrence in the two groups was 14 and 15 years. The mean time between the recurrence treat ment and a second recurrence was 7.5 years. Nine patients had RT in ad dition to the local resection. Of this group 3 patients (33%) develope d another recurrence. Five patients had local resection only, and of t his group 1 patient (20%) developed another recurrence. Of the group t hat had superficial parotidectomy, 3 patients had additional RT and on e of these patients (33%) developed another recurrence. Twenty-two pat ients had superficial parotidectomy only, and of this group 3 patients (14%) developed another recurrence. Only 2 of the 39 patients had com plications. One patient developed Frey's syndrome after superficial pa rotidectomy and 1 patient developed facial paralysis after RT. As in o ther series, the number of patients is inadequate to allow for firm co nclusions. However, it appears that when previous parotidectomy has be en performed, simple excision with a margin of surrounding tissue woul d seem appropriate. Parotidectomy should be carried out if not perform ed previously. In simple excision after previous parotidectomy, there is a greater risk to the facial nerve because of difficulty in disting uishing the facial nerve from surrounding scar tissue. Our preference is to use general anesthesia so that branches of the nerve are not par alyzed and stimulation of the nerve aids in safe dissection. The value of RT is still indeterminate.