Adaptive hypofractionated gamma knife radiosurgery for a large brainstem metastasis

Abstract

Background:To demonstrate how adaptive hypofractionated radiosurgery by gamma knife (GK) can be successfully utilized to treat a large brainstem metastasis - a novel approach to a challenging clinical situation.Case Description:A 42-year-old woman, diagnosed with metastatic nonsmall cell lung cancer in July 2011, initially treated with chemotherapy and tyrosine kinase inhibitors, developed multiple brain metastases March 2013, with subsequent whole brain radiotherapy, after which a magnetic resonance imaging (MRI) showed a significant volume regression of all brain metastases. A follow-up MRI in October 2013 revealed a growing brainstem lesion of 26 mm. Linear accelerator-based radiotherapy and microsurgery were judged contraindicated, why the decision was made to treat the patient with three separate radiosurgical sessions during the course of 1 week, with an 18% tumor volume reduction demonstrated after the last treatment. Follow-up MRI 2.5 months after her radiosurgical treatment showed a tumor volume reduction of 67% compared to the 1st day of treatment. Later on, the patient developed a radiation-induced perilesional edema although without major clinical implications. An MRI at 12 months and 18-fluoro-deoxyglucose positron emission tomography of the brain at 13 months showed decreased edema with no signs of tumor recurrence. Despite disease progression during the last months of her life, the patient's condition remained overall acceptable.Conclusion:GK-based stereotactic adaptive hypofractionation proved to be effective to achieve tumor control while limiting local adverse reactions. This surgical modality should be considered when managing larger brain lesions in critical areas.

The concept of rapid rescue radiosurgery in the acute management of critically located brain metastases: A retrospective short-term outcome analysis

“…The management of brain metastases in acute and subacute settings remains complex and requires tailored treatment. [ 43 44 ] Microsurgery followed by radiation delivery to the surgical cavity remains the cornerstone of brain metastasis management in terms of local recurrence free survival. [ 9 38 ] Upfront or adjunctive systemic treatments (immunotherapy, alternatively chemotherapy) may also be considered in selected patients.…”

“…[ 3 5 18 38 46 48 ] As a consequence of the shift away from WBRT, hypofractionated schedules delivered by means of LINAC-based instruments, proton beam devices, or gamma knife equipment (among others) are increasingly being used in the management of intractable brain metastases as they enable the clinician to achieve tumor control while limiting the risk of ARE. [ 11 12 13 17 18 19 20 22 23 33 35 36 40 41 43 44 46 50 ]…”

“…Different groups have reported the application of hypofractionated gamma knife radiosurgery in the management of large brain metastases,[ 23 33 50 ] including a particular technique known as adaptive radiosurgery;[ 43 44 51 ] when applied in well-defined acute and subacute settings, this image-guided procedure allows the surgeon to deal with life-threatening, neurologically destructive neoplasms in almost real-time conditions, achieving in many cases next to comparable debulking/decompressive surgical results during the course of treatment (days) and at postsurgery (weeks). The principle lies in dynamically adapting peripheral prescription and tumor bed dose distributions to ongoing tumor volume reduction at each GKRS with almost surgical precision while trying to withhold/minimize dose dissipation to healthy brain tissues as much as possible.…”

“…[ 11 12 13 17 18 19 20 22 23 33 36 40 41 50 ] Cases of prompt ablative results on large, aggressive, and eloquently located unresectable lesions using adaptive hypofractionated gamma knife radiosurgery have previously been reported. [ 43 44 51 ] The conceptual use of this hypofractionated radiosurgical technique in the management of intractable metastases in selected acute/subacute settings has been coined at our institution as Rapid Rescue Radiosurgery (RRR). [ 43 44 ]…”

“…[ 43 44 51 ] The conceptual use of this hypofractionated radiosurgical technique in the management of intractable metastases in selected acute/subacute settings has been coined at our institution as Rapid Rescue Radiosurgery (RRR). [ 43 44 ]…”