Effect of Tumor Bulk on Local Control and Survival of Patients With T1 Glottic Cancer: A 30-Year Experience

Purpose To evaluate the effect of tumor bulk on local control and survival of patients with T1 glottic cancer. Methods and Materials Effects of tumor bulk, T-stage, anterior-commissure involvement, treatment duration, and fraction size were analyzed in 208 patients; 136 had small tumors and 72 had bulky tumors. Anterior-commissure was involved in 54 patients. Treatment duration ranged from 39 to 64 days and fraction size ranged from 1.8 to 2.0 Gy. Median follow-up was 5.1 years. Results Five-year actuarial local control rates were 86.1% and 91.4% after radiotherapy and salvage laryngectomy. On univariate analysis, local control rates were 92.6% and 73.6% for small and bulky tumors ( p = 0.03), 89.6% and 75.9% for patients without and with anterior-commissure involvement ( p = 0.01), 92.6% and 75.6% when treatment duration was ≤50 days and >50 days ( p = 0.04), and 90.2% and 76.4% with 2 Gy and 1.8 Gy ( p = 0.02) per fraction. On multivariate analysis, tumor bulk was the only significant factor that affected local control ( p = 0.007). Ultimate local control rates after salvage were 97.1% and 80.5% for patients with small and bulky tumors. Disease-free survival rates at 5 years for small and bulky tumors were 96.3% and 84.7% ( p = 0.001). Median duration to recurrence for small tumors was 30 months as compared with 11 months for bulky tumors. Conclusion Tumor bulk is a highly significant prognostic factor for radiation control of T1 glottic cancer. Patients with bulky tumors had lower local control and disease-free survival rates and shorter duration to recurrence than those with small tumors.