Recurrent Glioma Paper

Recurrent gliomas are a challenge for the interdisciplinary neurooncology team: Independently of primary histology, most recurrences are characterized by substantial treatment resistance. Generally, the outcome from any modality is only modest. Since radiotherapy (RT) is a central part in primary treatment following neurosurgical resection or biopsy, much controversy exists regarding any additional radiation treatment. On the one hand, the fear of exceeding normal tissue tolerance and the attributed risk of symptomatic side effects have distracted radiation oncologist from delivering second courses of RT with higher doses [1-3]. Preclinical and clinical data have revealed that radiation memory of normal tissue is only limited over time, meaning
The availability of more precise radiation modalities has enabled the radiation oncologist to deliver local doses to precisely defined target volumes while sparing normal tissue: Techniques such as radiosurgery, for smaller volume, or fractionated stereotactic radiotherapy (FSRT) made widespread application of Re-RT in recurrent glioma possible. The first series reporting on a large group of patients with recurrent glioma prescribed 36 Gy in 2 Gy single fractions [5], and many centers initially followed this concept. Especially for patients with short intervals between primary and second RT, and/or with larger target volumes, such dose and fractionation concepts are safe; subsequent combination studies with systemic agents often retained this concept, avoiding any treatment-related side effects
Target volume definition for re-irradiation (Re-RT) of recurrent glioma generally includes any contrast enhancing lesions on T1-weighted MRI, adding a safety margin of approximately 5mm [5]. To encompass the real dimension of the tumor, the additional benefit of amino acid PET has been evaluated and is currently being assessed in a prospective clinical trial. On important factor on the outcome is extensive neurosurgical resection of glioma recurrences, where several groups have shown that the extent of resection (EOR) is associated with outcome [13-15]. However, in alleged completely resected glioma recurrences, Re-RT is withheld – most likely due to historical reasons.
In the present manuscript, we evaluate the impact of early Re-RT after neurosurgical resection in patients with recurrent gliomas as a preparation for a prospective clinical