Bevacizumab and gamma knife radiosurgery for first-recurrence glioblastoma.

INTRODUCTION: Glioblastoma (GBM) is the most common central nervous system malignancy in adults. Despite decades of developments in surgical management, radiation treatment, chemotherapy, and tumor treating field therapy, GBM remains an ultimately fatal disease. There is currently no definitive standard of care for patients with recurrent glioblastoma (rGBM) following failure of initial management. OBJECTIVE: In this retrospective cohort study, we set out to examine the relative effects of bevacizumab and Gamma Knife radiosurgery on progression-free survival (PFS) and overall survival (OS) in patients with GBM at first-recurrence. METHODS: We conducted a retrospective review of all patients with rGBM who underwent treatment with bevacizumab and/or Gamma Knife radiosurgery at Roswell Park Comprehensive Cancer Center between 2012 and 2022. Mean PFS and OS were determined for each of our three treatment groups: Bevacizumab Only, Bevacizumab Plus Gamma Knife, and Gamma Knife Only. RESULTS: Patients in the combined treatment group demonstrated longer post-recurrence median PFS (7.7 months) and median OS (11.5 months) compared to glioblastoma patients previously reported in the literature, and showed improvements in total PFS (p=0.015), total OS (p=0.0050), post-recurrence PFS (p=0.018), and post-recurrence OS (p=0.0082) compared to patients who received either bevacizumab or Gamma Knife as monotherapy. CONCLUSION: This study demonstrates that the combined use of bevacizumab with concurrent stereotactic radiosurgery can have improve survival in patients with rGBM.

Intracranial stereotactic radiosurgery.

Stereotactic radiosurgery (SRS) is the use of a single high dose of radiation, stereotactically directed to an intracranial region of interest, in order to create a lesion or obliterate a preexisting one. This technology has evolved over the years into the use of multiple radiation sources oriented at a variety of angles, thus permitting the creation of various treatment target shapes. This allows for non-open surgical treatment of intracranial pathologies, which significantly decreases the risk of morbidity. The destruction of pathological tissue following radiosurgery is a stepwise process that involves a number of different stages, beginning with the necrotic stage, followed by the resorption stage, and concluding with the glial scar formation stage. There are currently a number of different delivery methods of SRS, including linear accelerators, Gamma Knife units, and charged particle methods (Bragg-peak and plateau-beam). Various intracranial lesions exhibit different responses to radiosurgery; however, most lesions of appropriate size tend to respond favorably. Radiosurgery is used today in the treatment of brain metastases, meningiomas, vestibular schwannomas, sellar and suprasellar lesions, and arteriovenous malformations. SRS is widely used to treat functional conditions, such as trigeminal neuralgia and intractable tremor. The treatment of intracranial lesions with radiosurgery can result in undesirable effects on the adjacent normal brain, resulting in adverse radiation effects. The distinction between tumor progression and adverse radiation effects can be challenging but is aided by various imaging modalities. Treatment options for this condition include observation, corticosteroids, pentoxifylline and vitamin E, bevacizumab, laser-interstitial thermal therapy, and surgical resection.