Gamma Knife and complex targets – can we consider aggressive fractionated treatments?

Research into the use of Gamma Knife to treat primary brain tumours is ever evolving. In August 2022 the Journal of Neurosurgery (JNS) published the results of a feasibility study in a clinical article called, ‘Conventionally fully fractionated Gamma Knife Icon re-irradiation of primary recurrent intracranial tumors: the first report indicating feasibility and safety’.

Ian Paddick, Chief Physicist for Amethyst UK comments on the recently published article. He said; “This collection of case studies demonstrates the feasibility and potential safety of using Gamma Knife to deliver conventionally fractionated salvage treatments to recurrent tumours close to organs at risk that have received doses close to, or up to full tolerance.

“In addition, the article goes on to remind us that we have animal and retrospective clinical data that shows that brain tissue can recover significantly after irradiation – perhaps 75% in two years. This allows for reirradiation. Therefore, there may be room to be more aggressive when clinically needed.”

Why use Gamma Knife for this sort of treatment?

Gamma Knife is ideally suited to irradiation of complex targets to low doses. It can, for example, deliver complex treatment plans in 2Gy fractions in around 10 minutes, making it as efficient as a Linac. The feasibility study highlighted in the JNS article used a median number of 28 fractions. Ian Paddick concluded; “Gamma Knife’s excellent conformity and gradient is better suited to target tumours surrounded by previously irradiated tissue.”