Daily clinical radiotherapy of glioblastoma 15 years after the landmark Stupp´ trial: more controversies than standards?

Abstract

Background

The current standard of care of glioblastoma, the most common primary brain tumor in adults, has remained unchanged for over a decade. Nevertheless, some improvements in patient outcomes have occurred as a consequence of modern surgery, improved radiotherapy and up-to-date management of toxicity. Patients from control arms (receiving standard concurrent chemoradiotherapy and adjuvant chemotherapy with temozolomide) of recent clinical trials achieve better outcomes compared to the median survival of 14.6 months reported in Stupp’s landmark clinical trial in 2005. The approach to radiotherapy that emerged from Stupp´s trial, which continues to be a basis for the current standard of care, is no longer applicable and there is a need to develop updated guidelines for radiotherapy within daily clinical practice that address or at least acknowledge existing controversies in the planning of radiotherapy. The goal of this educational review is to provoke critical thinking about potentially controversial aspects in the radiotherapy of glioblastoma, including among others the issue of target definitions, simultaneous integrated boost technique, and hippocampal sparing.

Conclusion

In conjunction with new treatment approaches such as tumor-treating fields (TTF) and immunotherapy, future prospective studies evaluating the role of radiotherapy as well as its dose and target definition will be urgently needed.