Primary radiotherapy in the treatment of stage I and II oral tongue cancers: Importance of the proportion of therapy delivered with interstitial therapy

Abstract From January 1963 through December 1979, 103 patients with Stage T 1 N 0 and T 2 N 0 squamous cell carcinomas of the oral tongue were treated with definitive radiotherapy. The primary was Stage T 1 in 18 patients and T 2 in 85 patients. Therapy to the primary consisted of interstitial therapy only in 18 patients, 16–37 Gy in 2.4–4.0 Gy fractions followed by interstitial therapy to doses of 38–55 Gy in 31 patients, external therapy of 40–50 Gy with interstitial therapy of 20–40 Gy in 46 patients, and external beam only to doses of 45–82 Gy in 8 patients. Follow-up ranged from 2 to 290 months (median 159 months). Five of the 8 patients treated with external therapy alone and 6 of the 18 patients treated with interstitial therapy failed at the primary site. In those patients treated with a combination of external and interstitial therapy the 2-year local control rate was 92% for patients treated with external therapy to doses of p = .01). Conversely the risk of failure in the neck was directly related to the dose delivered by external beam therapy. In field recurrence occurred in 44% of patients receiving no therapy to the neck, 27% in those receiving