Radiotherapy of early glottic cancer Singapore, 1978-1981

This study analyses the results of primary radiotherapy for 44 patients with early glottic cancer (Tis, T1 stage) given at the Therapeutic Radiology Department, Singapore General Hospital during the 4-year period from 1978 to 1981. Irradiation was delivered using cobalt teletherapy with free set-ups, and without "air-gap" compensation. Total doses of 55Gy to 64Gy were given in daily fractions of 1.8Gy, treating five times a week. The crude 5-year survival rate for Tis/T1a tumours was 88.9% and for T1b lesions, 81%. On correcting for deaths from intercurrent disease, the survival rates improved to 95.5% and 92.6% respectively. In 33 cases where the quality of voice after radiation was assessed, 15 patients (45.4%) retained good voice quality with an additional 11 patients (33.3%) having acceptable voice quality. In seven cases the voice after radiation was rated as poor. Nine patients had local recurrence, giving a rate of 20.4%. One other patient had cervical node metastasis and subsequently developed lung secondaries. Surgery, solely or with re-irradiation, was an effective treatment for local recurrence. Re-irradiation alone failed to control any case with recurrence.