Clinical trials and retrospective studies in the field of radiation oncology often consider time-to-event data as their primary endpoint. Such studies are susceptible to competing risks, i.e. competing events may preclude the occurrence of the event of interest or modify the chance that the primary endpoint occurs. Competing risks are frequently neglected and the event of interest is analysed with standard statistical methods. Here, we would like to create awareness of the problem and demonstrate different methods for survival data analysis in the presence of competing risks.