[Radiotherapy for T1 and T2 carcinomas of the tongue: combination therapy using low-dose external irradiation and an interstitial implant].

Between January 1975 and October 1984, 114 previously untreated patients with squamous cell carcinoma of the tongue were treated by a radical course of irradiation at the Jikei University Hospital. Of these patients, eighty with T1 or T2 lesions are analyzed in this paper, some having been treated with an interstitial implant alone or with a combination of external irradiation and an interstitial implant. The two-year local control rate of the primary lesion reached 85% in T1 patients, and 68% for those graded T2. Late radiation injuries were seen in 18% of the cases with local control beyond one year. Most of these injuries, however, healed with conservative therapy. The cumulative 5-year survival rate was 75% in T1 patients, and 52% for those graded T2. The combination of low dose external irradiation (20-30 Gy) and an interstitial implant showed the same local control rate, the same incidence of late injury, and the same survival rate as those who received an interstitial implant alone. In cases that were given combination therapy, the sum dose of about 80 Gy was necessary for local control.