Anaplastic Transformation in Verrucous Carcinoma of the Oral Cavity After Radiation Therapy

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Abstract
The results of radiation therapy in 8 cases of verrucous carcinoma of the oral cavity are presented. This distinctive variant of epidermoid carcinoma presents as warty growth, often in elderly patients who chew tobacco, and follows a locally aggressive course without metastases. The microscopic pattern is characterized by bulbous rete ridges, total lack of anaplasia, and sharply circumscribed borders. Radiation ranged from 5,000 to 7,000 rads given in 5 to 7 weeks. At the completion of therapy there was excellent regression of all the lesions. Subsequent local recurrence of the primary tumor was observed in all cases. Only one patient in whom additional external irradiation and surgery were required to control a recurrence is free of tumor. Following radiation therapy a rapid anaplastic transformation of the histological pattern of the tumor and an unexpectedly aggressive clinical behavior were observed in 3 patients. The possibility that ionizing radiation may have had a causative effect in producing this change in biological character of these tumors is suggested, but there is no definite proof. From these observations, we conclude that radiation therapy is not the treatment of choice in these lesions.