Fig. 3
Efficacy of intensified RT to mitigate the negative prognosis associated with large tumor volumes. Illustration of the impact of tumor volume (x-axis) and efficacy of intensified RT (either 1.1 Gy + 2.0 Gy per day, total dose 68.0 Gy or 2.15 Gy per day, total dose 73.1 Gy) compared with conventional RT (CONV, 2.0 Gy per day, total dose 68.0 Gy) (Fig. 3A). The hazard ratio (HR, black solid line) for patients with a tumor volume larger than the indicated volume on the x-axis, was investigated using univariable cox-regression with overall survival as endpoint. The number of patients included in each analysis is shown in the upper part (light blue, dashed line). Based on A, a cut-off of GTV-T > 40 cm3 was chosen for exploratory post-hoc analyses. For high-risk patients (GTV-T > 40 cm3) the efficacy of intensified RT is illustrated with regards to the cumulative incidence of local failures (B), progression free survival (C) and overall survival (D). Stratification of patients based on T-classifications revealed no significant effects of intensified RT (Additional File 1: Fig. S8). CI: Confidence Interval