showed a trendp = 0.053
Univariate analyses using the cox regression analysis ( Tables S1 – S5 ) revealed that recurrence was a significant prognosticator for PFS (HR, 3.986; 95% CI: 1.246–12.754, p = 0.020); salvage IMRT is a significant predictor for PFS (HR, 3.009; 95% CI: 1.007–8.991, p = 0.049); the use of ENI significantly improves LPFS (HR, 0.136; 95% CI: 0.019–0.964, p = 0.046); recurrence showed a trend to predict DMFS (HR, 5.373; 95% CI: 0.981–29.426, p = 0.053), and OS (HR, 5.886; 95% CI: 0.931–37.231, p = 0.060); salvage IMRT showed a trend to predict LPFS (HR, 5.840; 95% CI: 0.821–41.522, p = 0.078).