Radical radiotherapy for early glottic cancer: Results in a series of 1087 patients from two Italian radiation oncology centers. II. The case of T2N0 disease

Abstract

To retrospectively evaluate local control rates, late damage incidence, functional results, and second-tumor occurrence according to the different patient, tumor, and treatment features in a large bi-institutional series of T2 glottic cancer. A total of 256 T2 glottic cancer cases treated consecutively with radical intent at the Florence University Radiation Oncology Department (FLO) and at the Radiation Oncology Department of the University of Brescia, Istituto del Radio "O. Alberti" (BS) were studied. Cumulative probability of local control (LC), disease-specific survival (DSS), and overall survival (OS) rates were calculated and compared in the different clinical and therapeutic subgroups by both univariate and multivariate analysis. Types of relapse and their surgical salvage were evaluated, along with the functional results of treatment. Late-damage incidence and second-tumor cumulative probability (STP) were also calculated. In the entire series, 3-year, 5-year, and 10-year OS rates were, respectively, 73%, 59%, and 37%. Corresponding values for cumulative LC probability were 73%, 73%, and 70% and for DSS, 89%, 86%, and 85%, taking into account surgical salvage of relapsed cases. Seventy-three percent of the patients were cured with function preserved. Main determinants of a worse LC at univariate analysis were larger tumor extent and impaired cord mobility. At multivariate analysis, the same factors retained statistical significance. Twenty-year STP was 23%, with second-tumor deaths less frequent than larynx cancer deaths (20 of 256 vs. 30 of 256). Incidence of late damage was higher in the first decade of accrual (22%) than in the last decade (10%, p = 0.03); the same was true for severe late damage (9% vs. 1.8%). Present-day radical radiotherapy can be considered a standard treatment for T2 glottic cancer. Better results are obtained in patients with less extended disease. Late damage is relatively infrequent, but a careful follow-up is warranted for early detection not only of relapses (because salvage surgery is feasible) but also of second malignant tumors, which constitute a relevant but not the leading cause of death in these patients and are potentially curable.