Prognostic factors for local control of early glottic cancer: The Rabin Medical Center retrospective study on 207 patients

Purpose: Different radiation therapy schedules and devices have been used o ver the last 20 years at Rabin Medical Center in patients with early glotti c cancer. The aim of the present retrospective analysis was to identify the subgroup of patients at high risk of failure of radiation treatment. Materials and Methods: Between 1974 and 1994, 207 patients with squamous ce ll carcinoma of the glottis, 182 Stage T1 and 25 Stage T2, underwent defini tive radiation therapy. During this period, treatment was administered with different radiation devices (Co-60 or 6-MV X ray), using different dose/fr action protocols (1.8 or 2 Gy per day, 5 or 6 fractions per week), total do ses (42-77.4 Gy), overall radiation times, and delays. These treatment vari ables, in addition to certain patient and tumor characteristics, were corre lated with local control at a median follow-up of 57 months (range 18-265 m onths). Results: The 5-year local control rates for T1 and T2 tumors were 88% and 7 3%, respectively. Univariate analysis showed that smoking, diabetes mellitu s, anterior commissure involvement, T stage, and extension of tumor to one third or more of the vocal cord were highly significantly correlated with d ecreased local control. None of the treatment variables, including dosage a t which complete tumor regression was noted, were found to be predictive. B y multivariate analysis, only anterior commissure involvement was found to be highly significant (risk ratio 1.9, 95% CI 1.2-3.0, p = 0.027), and T st age was borderline significant (risk ratio 1.6, 95% CI 1.0-2.5, p = 0.054). Conclusion: This study suggests that only two tumor characteristics are pre dictive of local failure of early glottic cancer: anterior commissure invol vement and T stage. Treatment variables apparently do not influence local c ontrol. (C) 1999 Elsevier Science Inc.