Adaptive hypofractionated gamma knife radiosurgery in the acute management of large thymic carcinoma brain metastases

Abstract

Background:Brain metastases often lead to serious neurological impairment and life threatening states. Their acute management remains complex, particularly in the case of rare malignancies with aggressive evolution. In large single lesions, open surgery followed by radiation to the surgical cavity is widely regarded as the best approach; yet in many cases, microsurgery is not feasible due to the lesion's critical location and/or the number of brain metastases present. We report the effects of adaptive hypofractionated gamma knife radiosurgery in the acute management of critically located thymic carcinoma metastases.Case Description:A 50-year-old male with metastatic thymic carcinoma was treated with radiosurgery for two large supratentorial brain metastases (M3 and M4) adjacent to eloquent areas and one smaller cerebellar metastasis (M2). M3 and M4 were treated with adaptive hypofractionated gamma knife radiosurgery, showing a dramatic volume reduction 4 weeks after treatment completion without radiation-induced side effects. Thirteen months later, two new small, threatening supratentorial lesions (M5-M6) were treated with the same technique. Interestingly, M2 (treated with standard single fraction) and M5-M6 developed local adverse radiation events. The patient's general and neurological status remained next to normal by the time of paper submission.Conclusion:The application of adaptive hypofractionated radiosurgery in this acute setting proved effective in terms of rapid tumor ablation, with salvage of neurological functionality and limited toxicity. We have called the overall procedure rapid rescue radiosurgery (RRR). A systematic study of past and ongoing RRR-treatments is warranted and in progress.

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 ]…”