EFFECT OF TUMOR BULK ON LOCAL-CONTROL AND SURVIVAL OF PATIENTS WITH T1 GLOTTIC CANCER

Purpose: To evaluate the effect of tumor bulk in relation to various; tumor-related prognostic factors and treatment-related Variables on lo cal control and survival of patients with T1 N0 M0 squamous cell carci noma of the glottis. Materials and methods: In 114 patients with T1 sq uamous cell carcinoma of the glottic larynx who were irradiated with c urative 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 tre atment time on local control and survival. Tumors were classified retr ospectively as small surface lesions or bulky tumors. Seventy-seven pa tients had small lesions and 37 had bulky tumors. The anterior commiss ure was involved with cancer in 43 patients. The overall duration of i rradiation 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 involvi ng the anterior commissure showed an adverse effect on local control, whereas the overall duration of irradiation had a borderline significa nce. The actuarial local control rate was 91% for small tumors and 58% for bulky tumors (P = 0.0002), 88% when the anterior commissure was n ot involved and 67% when the anterior commissure was involved (P = 0.0 1) and 89% when radiation was given in less than 50 days and 73% when irradiation exceeded 50 days (P = 0.06). On multivariate analysis, tum or bulk was the only significant factor that affected local control (P = 0.02). The 5-year actuarial survival for all patients was 73% and t he disease-free survival was 92%. Conclusion: This study shows that tu mor bulk has a highly significant effect on the radiation control of T 1 glottic cancer. Patients who had bulky tumors had lower local contro l and disease-free survival rates than those patients who had small tu mors. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.