Purpose: Radiotherapy (RT) is often the therapy of choice for patients with Stage T2 glottic carcinoma. This retrospective study updated the results of RT for patients treated at our center. The primary focus of this study was whether a policy of using hyperfractionated RT for these patients resulted in a therapeutic gain.
Methods and materials: A search of the database of patients treated in the Department of Radiation Oncology at The University of Texas M. D. Anderson Cancer Center was performed to identify patients with Stage T2 glottic carcinoma treated with RT alone between 1970 and 1998. A total of 230 patients formed the study cohort.
Results: The median follow-up for all patients was 82 months. Of the 230 patients, 180 were treated with parallel-opposed fields, and the median field size was 30 cm(2). Eighty-one patients (36%) were treated with twice-daily fractionation to 74-80 Gy. Eighty-nine patients (38%) were treated with 32-75 Gy at 2-Gy per fraction once daily, and 57 patients (25%) were treated with 2.06-2.26 Gy, once daily, to 66-70 Gy. The 2- and 5-year actuarial local control rate was 75% and 72%, respectively. After salvage therapy, the ultimate 5-year local control and disease-specific survival rate was 91% and 92%, respectively. The presence of subglottic extension and treatment with a daily dose of < or =2 Gy were associated with poorer local control (p <0.01) on both univariate and multivariate analyses. The 5-year local control rate for patients treated with twice-daily and once-daily RT was 79% and 67%, respectively (p = 0.06).
Conclusion: The 5-year local control rates with hyperfractionated RT for Stage T2 glottic carcinoma approach 80%. Patients treated with twice-daily fractionation to a median dose of 77 Gy had an improvement in local control compared with patients treated with 70 Gy in 35 fractions. The Radiation Therapy Oncology Group is testing these two fractionation schedules in a randomized study. High control rates were also seen in selected patients treated with hypofractionated schedules, leaving the question of the optimal schedule for patients with Stage T2 disease unanswered.