Definitive radiotherapy for T3 squamous cell carcinoma of the glottic larynx.

Purpose: To report the results of radiotherapy alone for stage T3 squamous cell carcinoma of the true vocal cord and compare these data with those obtained with other treatment modalities.

Methods And Materials: Seventy-five patients with previously untreated T3 squamous cell carcinoma of the glottic larynx were treated with curative intent with radiotherapy alone (73 patients) or followed by a planned neck dissection (two patients) at the University of Florida between September 1966 and August 1994. No patient received adjuvant chemotherapy. All patients were monitored for at least 2 years and 85% had a minimum follow-up duration of 5 years. No patient was lost to follow-up evaluation.

Results: The 5-year local control and ultimate local control rates were 63% and 86%, respectively. The volume of the primary tumor (which was calculated on pretreatment computed tomographic [CT] scans in 38 patients) was inversely related to local control with larynx preservation: < or = 3.5 cm3, 20 of 23 (87%) versus greater than 3.5 cm3, four of 14 (29%) (P = .0005). There was no apparent relationship between local control after radiotherapy as a function of whether the vocal cord regained mobility or remained fixed during or shortly after completion of treatment. The 5-year absolute and cause-specific survival rates were 54% and 78%, respectively. Multivariate analysis showed that pretreatment tracheostomy was significantly related to diminished cause-specific survival (P = .0345).

Conclusion: Radiotherapy alone results in long-term local-regional control and survival rates that are comparable to those obtained with surgery. It is unclear whether induction or concomitant chemotherapy is associated with improved local-regional control and survival compared with radiotherapy alone.