The role of radiosurgery in the acute management of fourth ventricle compression due to brain metastases

Abstract

Background:Approximately 20–30% of all intracranial metastases are located in the posterior fossa. The clinical evolution hinges on factors such as tumor growth dynamics, local topographic conditions, performance status, and prompt intervention. Fourth ventricle (V4) compression with secondary life-threatening obstructive hydrocephalus remains a major concern, often requiring acute surgical intervention. We have previously reported on the application of adaptive hypofractionated Gamma Knife Radiosurgery in the acute management of critically located metastases, a technique known to us as rapid rescue radiosurgery (3R). We report the results of 3R in the management of posterior fossa lesions and ensuing V4 decompression.Case Descriptions:Four patients with V4 compression due to posterior fossa metastases were treated with 3R by three separate gamma knife radiosurgical sessions (GKRS) over a period of seven days. Mean V4 volume was 1.02 cm3 at GKRS 1, 1.13 cm3 at GKRS 2, and 1.12 cm3 at GKRS 3. Mean tumor volume during the week of treatment was 10 cm3 at both GKRS 1 and 2 and 9 cm3 at GKRS 3. On average, we achieved a tumor volume reduction of 52% and a V4 size increase of 64% at the first follow-up (4 weeks after GKRS 3). Long-term follow-up showed continued local tumor control, stable V4 volume, and absence of hydrocephalus.Conclusion:For this series, 3R was effective in terms of rapid tumor ablation, V4 decompression, and limited radiation-induced toxicity. This surgical procedure may become an additional tool in the management of intractable posterior fossa metastasis with V4 compression.

Adaptive radiosurgery based on two simultaneous dose prescriptions in the management of large renal cell carcinoma brain metastases in critical areas: Towards customization

“…In this particular case, the positive clinical and radiographic evolution of Met 1 and Met 2 post-RRR were similar to previous reports from other authors and Sinclair et al [24,[26][27][28][29][30] Unfortunately, a deeper analysis of the kinetic effectiveness of RRR compared to single fraction treatments or other oligostaged approaches remains complex and will continue to be a source of bias; indeed, although a few groups have studied the specific effects of stereotactic hypofractionated radiotherapy on tumor kinetics in renal histology, [33,37] to the best of our knowledge, there are no or few studies comparing the ablative dynamics of brain lesions post single fraction versus post hypofractionation. Nonetheless, based on (i) the volumetric data post treatment of this case [Tables 1-3] (ii) our institutional experience, [26][27][28][29][30] and (iii) the available medical literature, [1,24,32,36] we suggest that, in the context of this case, the expeditious and lasting ablative effects triggered by this double prescription technique extended survival. [24,[26][27][28][29][30] Moreover, the fact that our patient developed an ARE at the site of Met 1 and Met 2 despite a hypofractionated approach, suggests that SF-GKRS would have led to greater perilesional edema and possibly substantial radionecrosis resulting in further neurologic damage.…”

“…Nonetheless, based on (i) the volumetric data post treatment of this case [Tables 1-3] (ii) our institutional experience, [26][27][28][29][30] and (iii) the available medical literature, [1,24,32,36] we suggest that, in the context of this case, the expeditious and lasting ablative effects triggered by this double prescription technique extended survival. [24,[26][27][28][29][30] Moreover, the fact that our patient developed an ARE at the site of Met 1 and Met 2 despite a hypofractionated approach, suggests that SF-GKRS would have led to greater perilesional edema and possibly substantial radionecrosis resulting in further neurologic damage. Several studies seem to support the latter proposal.…”

“…e rationale behind RRR can be found elsewhere in the literature. [26][27][28]31] Follow-up MRI at 1, 3, and 6 months confirmed subsequent tumor volume reduction of Met 1 with ensuing significant improvement of the patient's motor function […”

“…Aiming to decrease the risk of SF-GKRS associated ARE, different groups have explored alternative schedules with the aim of reducing toxicity whilst optimising local control; in this framework, volume-staged hypofractionation has become a vivid subject of discussion. [1,[26][27][28][29][30]36] Yamamoto et al conducted a three-stage gamma knife treatment study on 78 patients with e inclusion of underlying radiobiological parameters and inherent physio-mathematical variables are quintessential for triggering key microenvironmental events involving vascular damage and antitumor immunity. e rationale of the procedure can be found elsewhere.…”

Supratentorial and infratentorial brain metastases: a single centre, retrospective cohort study

“…Cerebellar lesions often present differently to supratentorial metastases, commonly with characteristic signs of headache, ataxia, and nausea/vomiting [4]. Additionally, these lesions can rapidly cause obstructive hydrocephalus, brainstem compression, and herniation with acute neurological decline [5]. As a result, previous research has called for infra-and supratentorial metastasis patients to be treated as separate cohorts [6].…”