Brachytherapy of Intracranial Gliomas

Interstitial implantation of radioactive materials (brachytherapy [BT]) has been designed to protractedly deliver a high radiation dose to a well-defined target volume, while minimizing irradiation of the adjacent normal tissues. Even though promising results have been reported over time, the role of this treatment modality in the management of brain tumors is still poorly defined, and only a few centers worldwide apply it in clinical practice. Nevertheless, temporary or permanent interstitial implantation of low activity (<20 mCi) and low dose rate (≤10 cGy/h) iodine-125 (125I) seeds as possible therapy of intracranial gliomas is currently undergoing a definite revival, and several indications for its use have been identified. Generally, 125I-BT may be considered a reasonable option in cases of unresectable, well-circumscribed, either newly diagnosed or recurrent tumors with a diameter of ≤4 cm, virtually in any location within the brain. Importantly, this treatment does not narrow down the spectrum of the possible subsequent salvage therapeutic options, since neither repeated interstitial nor additional external beam irradiation at the time of tumor progression after BT is associated with a significantly increased risk of radiogenic complications. Using correct patient selection criteria, appropriate surgical technique, and established treatment parameters, would make BT a truly minimally invasive procedure with a low risk of complications and reasonable efficacy.