Results of radiotherapy for primary subglottic squamous cell carcinoma.
To retrospectively evaluate the outcome after radical radiotherapy (RT) and surgical salvage and assess the risk of late toxicity for patients with primary subglottic squamous cell carcinoma treated at our center. Between 1971 and 1996, 43 patients with primary squamous cell carcinoma of the subglottis (35 men, 8 women) were treated with radical RT. All received megavoltage irradiation, most commonly to a dose of 50-52 Gy in 20 fractions during 4 weeks (39 patients). The median follow-up was 4.2 years. Local control was achieved with RT alone in 24 (56%) of the 43 patients: 7 of 11 with T1, 8 of 12 with T2, 4 of 8 with T3, and 5 of 12 with T4. The 5-year actuarial local relapse-free rate was 52%. Subsequent local control was achieved in 11 of the 13 patients with failed RT and attempted surgical salvage, for an ultimate local control rate of 81.4% (35 of 43). The 5-year overall and cause-specific actuarial survival rate was 50.3% and 66.9%, respectively. No patients developed Grade 3 or 4 late radiation morbidity. These data support the use of primary RT in the treatment of patients with primary squamous cell carcinoma of the subglottis as an appropriate treatment approach providing an option for laryngeal conservation.