Rotating Gamma System Irradiation: A Promising Treatment for Low-grade Brainstem Gliomas

Abstract

Brainstem gliomas account for about 20% of primary brain tumors in children and for <2% of gliomas in adult patients (1-3). Gliomas of the brainstem are most commonly located in the pons, but are also found in the mesencephalon, the cerebellar peduncles or the medulla oblongata (4). A tumor located in the brainstem can be associated with severe clinical or even life-threatening symptoms, since this part of the brain regulates motion functions, as well as respiratory and circulatory functions. Such tumors include low-and high-grade lesions. The median survival time for patients with a brainstem glioma is about 10 months in children and 30-40 months in adult patients (5). The prognosis depends on the grade according to the World Health Organization (WHO) (6). In a retrospective study from the United States, median survival was 77 months for patients with WHO grade II lesions, 21 months for those with grade III lesions and 15 months for those with grade IV lesions (5). A great amount of research has been carried out on the treatment of higher grade (III or IV) lesions, whereas fewer data are available for patients with low-grade (grade II) gliomas (7-11). Therefore, the present study focused on low-grade gliomas of the brainstem and aimed to provide additional data for this less common situation.Since complete surgical resection is not safely possible in many of these patients, radiotherapy is the most common treatment. In order to allow for optimal sparing of normal tissues and structures surrounding the tumor, radiotherapy of brainstem gliomas should ideally be performed with highprecision techniques such as intensity-modulated radiotherapy, fractionated stereotactic radiation therapy or stereotactic radiosurgery (SRS). SRS is defined as singlefraction treatment, mostly performed with a linear accelerator or a gamma system. Two gamma systems are used for radiosurgery of cerebral lesions, including those located in the brainstem. The classic Gamma-Knife was already introduced about 50 years ago by Lars Leksell (12). The other system, the rotating gamma system (RGS), was developed in the late 1990s (13). The latter system includes technical features of the classic Gamma-Knife (Cobalt-60 sources) and linear acceleratorbased radiosurgery (a rotating gantry). Although radiosurgery with a gamma system appears to be a reasonable option for 957

The Epidemiological Characteristics and Prognostic Factors of Low-Grade Brainstem Glioma: A Real-World Study of Pediatric and Adult Patients

“…So we did not include these 61 patients in the data set so as to make reliable conclusion. Given that the surgical experience is growing and efforts are made to attempt preferable adjuvant therapy methods (16,(33)(34)(35), the present study based on cases reported between 2004 and 2015 could not capture the most updated clinical evidence.…”

Hypofractionated Gamma Knife Radiosurgery: Institutional Experience on Benign and Malignant Intracranial Tumors

“…Advances in stereotactic imaging and computer software further enhanced treatment planning and responsiveness (3,4). In the current neuro-oncology era, GKRS is frequently considered as upfront and adjuvant treatment in combination with surgical resection, or as a minimally invasive alternative in patients not eligible to surgery (5)(6)(7)(8)(9)(10).…”