Definitive radiotherapy for early glottic carcinoma: prognostic factors and implications for treatment

Purpose: Treatment and disease-related factors were analyzed for their influence on the outcome of patients treated definitively with irradiation (RT) for early glottic carcinoma. Methods and Materials: One hundred two patients with stage T1 or T2 glottic carcinomas were treated definitively with RT from December 1983 through September 1993. Median follow-up time was 63 months. Factors analyzed for each patient included age, sex, stage, anterior commissure involvement, surgical alternative, histologic differentiation, field size, total dose, fraction size, and total treatment time. Survival analysis methods were employed to assess the effects of these factors on local control and complication rates. Results: The 5-year local control rates by stage were as follows: T1a, 92%; T1b, 80%; T2a, 94%; and T2b, 23%. By univariate analysis, factors found to have a significant impact on local control were stage, surgical alternative, fraction size, anterior commissure involvement, and overall treatment time. By multivariate analysis, stage, field size, and fraction size were the only significant factors that independently influenced local control. Conclusions: The inferior control rate for stage T2b lesions has implications for treatment. Our study supports the conclusions of reports in the literature showing that low fraction size negatively influences outcome in patients with early glottic cancer