Definitive radiotherapy for 114 cases of T3N0 glottic carcinoma: influence of dose-volume parameters on outcome.

Background and Purpose: Assuming that the dose-response curve for T3N0M0 glottic carcinoma is steep and that the rate of occult lymph node metastases is low, it should be possible to employ high biological tumour doses to modest target volumes and thereby maximise laryngeal control without compromising final neck control. Within the constraints of a retrospective study we aim to examine this policy with respect to local control, incidence of nodal relapse and late complications.
Materials and Methods: One hundred and fourteen patients with T3N0M0 glottic carcinoma who received a 3-week schedule of radical radiotherapy between 1986 and 1994 were analysed. The median age was 67 years (range, 34-85 years) and the median follow-up for living patients was 4.8 years (1.9-8.9 years). There were no strict selection criteria for those patients treated with radiotherapy.
Results: The 5-year overall survival was 54%. The 5-year local control with radiotherapy and the ultimate loco-regional control following salvage laryngectomy were 68 and 80%, respectively. Nine patients (8%) suffered a regional nodal relapse but only three of these (3% overall) occurred in the absence of local failure. Four patients (3.5%) developed serious late complications requiring surgical intervention (three received 55 Gy and one 52.5 Gy).
Conclusions: It is possible to employ maximum tolerable doses to specific target volumes and thereby exploit the dose response demonstrated and minimise major late effects. The use of modest target volumes resulted in only 3% of patients requiring surgery that might have been avoided had prophylactic neck irradiation been employed.