Radiotherapy. The mainstay in the treatment of early glottic carcinoma. Early squamous cell carcinoma of the glottis may be effectively treated with surgery or radiation therapy. Controversy exists as to whether radiation therapy effects survival at the expense of vocal function by ultimately requiring more total laryngectomies for salvage of local tumor recurrence. This study reviewed the medical records of 185 patients with T1 or T2, NO invasive squamous cell carcinoma of the glottis treated with primary radiation therapy between 1969 and 1984. All patients were followed up for a minimum of 5 years after completion of therapy. One hundred sixty-one patients met the criteria for local control analysis. Radiation therapy controlled disease in 93% (105 of 113) of patients with T1 lesions and 73% (38 of 48) of those with T2 tumors. Ultimate control of disease for T1 and T2 lesions, including surgical salvage, was 111 (98%) of 113 and 44 (92%) of 48 patients, respectively. The rate of successful surgical salvage was 75% (T1) and 70% (T2). The T2 lesions with impaired vocal cord mobility or anterior commissure disease were identified as being at increased risk for recurrence after primary radiation therapy. Overall voice preservation was 90%. Our data demonstrate that radiation therapy effects disease-free survival rates that are comparable to those produced by surgery, without sacrificing voice. Although a small percentage of patients with selected early glottic lesions may be more effectively treated with primary conservation surgery, these data do not support a change in philosophy concerning primary treatment of early glottic cancer with radiation therapy. 