The authors sincerely apologize for an incorrectness in Fig. 1. This was drawn to their attention by a guest user of the website www.predictcancer.org where the variables in the model derived from the paper can be used interactively. The labels for the clinical T-Stage variable were incorrectly ordered as T1, T2, T3, T4. The correct order should be T1, T2, T4 and T3. In addition, the endpoint in Fig. 1 refers to Progression Free Survival. The corrected Fig. 1 and corrected legend are presented below. The authors do not think this mistake affects the results and conclusions of the paper, because the HRs in Table 2 of the original article already indicated higher values for T3 compared to T4 tumor. At first glance this appears counterintuitive, however in previous studies  it was also demonstrated that higher T-stage was not associated with worse outcome after chemoradiation, because the most prominent factor appeared to be tumor volume. In this respect, a small tumor with bone invasion (i.e. T4) might respond more favourably to radiation, compared to a more voluminous T3 tumor without bone invasion.