Effect of tumor bulk on local control and survival of patients with T1 glottic cancer

Abstract

Purpose: To evaluate the effect of tumor bulk in relation to various tumor-related prognostic factors and treatment-related variables on local control and survival of patients with T1 N0 M0 squamous cell carcinoma of the glottis. Materials and methods: In 114 patients with T1 squamous cell carcinoma of the glottic larynx who were irradiated with curative intent, we determined the effect of tumor bulk in relation to mucosal extent (stage and anterior commissure involvement), histologic differentiation and various radiation factors, especially overall treatment time on local control and survival. Tumors were classified retrospectively as small surface lesions or bulky tumors. Seventy-seven patients had small lesions and 37 had bulky tumors. The anterior commissure was involved with cancer in 43 patients. The overall duration of irradiation ranged from 39 to 64 days. The median follow-up time was 6 years (range 5–24 years). Results: The 5-year actuarial local control rate for all patients was 82% after radiotherapy and 92% after salvage laryngectomy. On univariate analysis, bulky tumors and tumors involving the anterior commissure showed an adverse effect on local control, whereas the overall duration of irradiation had a borderline significance. The actuarial local control rate was 91% for small tumors and 58% for bulky tumors ( P=0.0002), 88% when the anterior commissure was not involved and 67% when the anterior commissure was involved ( P=0.01) and 89% when radiation was given in less than 50 days and 73% when irradiation exceeded 50 days ( P=0.06). On multivariate analysis, tumor bulk was the only significant factor that affected local control ( P=0.02). The 5-year actuarial survival for all patients was 73% and the disease-free survival was 92%. Conclusion: This study shows that tumor bulk has a highly significant effect on the radiation control of T1 glottic cancer. Patients who had bulky tumors had lower local control and disease-free survival rates than those patients who had small tumors.