Management of adverse radiation effects after radiosurgery

Stereotactic radiosurgery (SRS) is a well-established tool in the armamentarium for the treatment of metastatic tumors to the brain. Although SRS has proven to be highly effective in the management of brain metastases, it is not without risk. Despite selective targeting of lesions and the sharp dose fall-off associated with radiosurgical treatments, adverse radiation effects (AREs) can and do occur, albeit at a low rate, just as has been reported after conventional fractionated radiation therapy. One of the most vexing clinical scenarios for SRS practitioners is the distinction between ARE and tumor recurrence or progression after radiosurgery. Differentiation of these two entities is critical, as further treatment options range from oral medications to invasive surgical resection. In this review, we define AREs and discuss the possible mechanisms that produce them. Efforts to distinguish between ARE and tumor progression also are explored. Finally, a management algorithm for AREs is proposed.