Radiotherapy for patients with early-stage glottic carcinoma: univariate and multivariate analyses in a group of consecutive, unselected patients

Abstract

Background: Radiotherapy (RT) has a remarkable success rate in the treatment of patients with glottic carcinoma. The objectives of the current study were to assess the results in a group of consecutive patients with comparable characteristics who were treated with RT (6-megavolt photon linear accelerator) and to determine the prognostic factors that may influence local control in patients with early-stage glottic carcinoma. The impact on local control of tobacco smoking and second primary malignancies also was investigated.

Methods: Four hundred ten patients with T1-T2 squamous cell carcinoma of the glottis who were treated between 1986 and 2001 were analyzed retrospectively with regard to local control and overall survival. Potential prognostic factors for local control were evaluated with univariate and multivariate models. The impact of technologic advances also was evaluated.

Results: The 5-year and 10-year overall survival rates were 83% and 63.5%, respectively. The overall 10-year local control rate for patients with T1-T2 glottic carcinoma was 89%. The median time to recurrence was 7 months. Univariate analysis showed that tumor category, tumor size, macroscopic appearance of the lesion, RT fraction size, persistent edema, year of RT treatment, unchanged dysphonia, and surgical option all had a significant influence on local control; whereas multivariate analysis showed that only persistent dysphonia and year of RT treatment were significantly associated with increased local control. A 22.2% rate of second primary malignancies was reported: second primary tumors were the major cause of death in the patients studied. Only 2 patients died of laryngeal carcinoma; 304 patients were alive with their disease in complete remission, 1 patient was alive with recurrent laryngeal carcinoma after undergoing salvage surgery, and 103 patients died of either intercurrent disease or a second primary tumor.

Conclusions: The use of a 6-megavolt photon linear accelerator achieved a high rate of local control in patients with T1-T2 glottic carcinoma. Dysphonia and the year of RT treatment were the most important prognostically significant factors for patient outcome. The occurrence of a second primary tumor was the most frequent cause of death, especially among patients who did not stop smoking after a diagnosis of glottic carcinoma.