Influence of local surgery and radiotherapy on the natural history of pleomorphic adenomas.

We have analysed the interval between first treatment and tumour recurrence in 65 patients with parotid pleomorphic adenomas which had recurred following local excision. Our results indicate that 5 years is an inadequate period of follow-up and that 10-20 years may be more realistic. Radiotherapy given to 17 patients after local excision of their tumours was found to have had no significant advantageous effect in terms of recurrence-free interval either before or following formal parotidectomy or in limiting the ultimate surgery required. Major complications directly attributable to radiotherapy developed in at least 3 of these 17 patients. Malignant transformation of the pleomorphic adenoma has occurred in three patients, two of whom had been subjected to radiotherapy. We advise that caution is exercised in the interpretation of results of local excision and radiotherapy in this disease. In view of the fact that an alternative and apparently superior treatment is available in the form of formal parotidectomy, we urge that this should be universally adopted for the management of both primary and recurrent pleomorphic adenomas.