The evolving role of reirradiation in the management of recurrent brain tumors

Abstract

Despite aggressive management consisting of surgery, radiation therapy (RT), and systemic therapy given alone or in combination, a significant proportion of patients with brain tumors will experience tumor recurrence. For these patients, no standard of care exists and management of either primary or metastatic recurrent tumors remains challenging.Advances in imaging and RT technology have enabled more precise tumor localization and dose delivery, leading to a reduction in the volume of health brain tissue exposed to high radiation doses. Radiation techniques have evolved from three-dimensional (3-D) conformal RT to the development of sophisticated techniques, including intensity modulated radiation therapy (IMRT), volumetric arc therapy (VMAT), and stereotactic techniques, either stereotactic radiosurgery (SRS) or stereotactic radiotherapy (SRT). Several studies have suggested that a second course of RT is a feasible treatment option in patients with a recurrent tumor; however, survival benefit and treatment related toxicity of reirradiation, given alone or in combination with other focal or systemic therapies, remain a controversial issue.We provide a critical overview of the current clinical status and technical challenges of reirradiation in patients with both recurrent primary brain tumors, such as gliomas, ependymomas, medulloblastomas, and meningiomas, and brain metastases. Relevant clinical questions such as the appropriate radiation technique and patient selection, the optimal radiation dose and fractionation, tolerance of the brain to a second course of RT, and the risk of adverse radiation effects have been critically discussed. Graphical Abstract

Hypofractionated stereotactic re-irradiation for progressive glioblastoma: twelve years’ experience of a single center

“…The most important concerns about reirradiation are radionecrosis and the potential significant toxicity that may arise with a second course of irradiation. Radionecrosis rates ranging from 0 to 37% have been reported with radiosurgery and hypofractionated SRT series [ 5 ]. The radionecrosis rate of 22% in our study aligns with the existing literature and 82% of them were asymptomatic.…”

“…The literature has a wide range of outcomes with both stereotactic radiosurgery and hypofractionated SRT. Using these techniques, the median survival rates range from 7 to 13 months, 1-year survival rates are reported between 30 and 55%, and neurological toxicity rates range from 5 to 20% [ 5 ]. Yet, due to the retrospective and heterogeneous nature of the series, it is challenging to ascertain the optimal dose/fraction schedule, target volume delineation protocol, and subgroups that will benefit most from SRT.…”