Radiotherapy of T1 and T2 glottic cancer: analysis of anterior commissure involvement.

From January 1984 to December 1993, 184 patients with previously untreated T1 and T2 (UICC 1987) laryngeal glottic cancer underwent radiotherapy at Hyogo Medical Center for Adults. The prognostic variables analyzed included sex, age, smoking index, T stage, tumor size, tumor type, gross anterior commissure involvement (gross ACI), histological differentiation, administered dose, TDF, overall treatment time, chemotherapy, initial response, and the dose required to achieve CR. Both univariate and multivariate analyses were performed. The T stage, tumor size, and gross ACI were significant variables in univariate analysis, while the tumor type and gross ACI were significant on multivariate analysis. The 5-year recurrence-free survival of patients with gross ACI was significantly worse than that of those without ACI (57.6% vs. 89.9%). Among gross ACI patients, the recurrence-free survival of those treated with 70-72 Gy was superior to that of those receiving 60-62 Gy, suggesting that at least 70 Gy was necessary to control such diseases.