Statistical analyses
Structural and biochemical recurrences were estimated using the
competing risk methods. DFS and OS were estimated using the
Kaplan–Meier method. The significance of predictors, such as
biochemical control, structural control, and OS, were assessed in
univariate and multivariate analyses using cox proportional hazard
models. Statistical analyses using cox regression models were also
performed to compare the rates of biochemical recurrence, structural
recurrence, and OS between patients with tracheal involvement versus
other forms of ETE. Dosimetry parameters were compared using unpaired
t-tests. A two-sided p- value <0.05 was considered
statistically significant for all measures