Radiotherapeutic management and results of T1N0, T2N0 carcinoma of the oral tongue: Evaluation of boost techniques

Abstract

This paper presents the total experience of radiation therapy of early carcinoma of the oral tongue at the Massachusetts General Hospital over a span of 25 years. External beam radiotherapy with various boost techniques were used including interstitial implant, and intra-oral cone (IOC) using kilovoltage (250 kV HVL 1.53 mm Cu) radiations or low megavoltage electron beam. We evaluated our results of boost techniques for treatment of patients with T1NO and T2NO lesions and determined the 5-year actuarial local control rates of these treatment methods. From 1960–1978, 49 patients were treated by implant and 20 by intra-oral cone kilovoltage radiation. From 1979–1985, 73 patients were treated by intra-oral cone electron beam with minimal follow-up of 2 years. The 5-year actuarial local control rates for T1N0 and T2NO lesions showed 54% after implant, 50% after intra-oral cone kilovoltage, and 86% after intra-oral cone electron beam boost with a p value of 0.0001. For the T1N0 lesions, the corresponding rates were 77%, 62%, and 90%, and for T2NO lesions the rates were 54%, 43%, and 85%, respectively. In the absence of a prospective randomized trial, direct comparison of various boost techniques is not possible due to selection factor for therapy, increased clinical and technical expertise, and improvement in equipment. Therefore, no definitive conclusions can be made regarding optimum “boost” therapy. The data presented herein suggest that intra-oral cone electron beam boost technique is superior to interstitial implant for boosting early carcinoma of the tongue.