Secondary concern.

Radiosurgery offers an excellent scalpel-free treatment for many benign conditions, but with high cure rates come high concerns for secondary malignancy. Such is the focus of this international pooled analysis of nearly 5000 patients treated with Gamma Knife for mostly meningioma (30%), AVM (22%), vestibular schwannoma (21%), or trigeminal neuralgia (12%). All included patients had a minimum follow-up of 5 years with a median follow-up of over 8 years. Radiation-associated tumors were defined as those that developed within the 2 Gy isodose line. Overall, there were two cases (0.0006%) of transformation to malignant schwannoma and one case (0.0002%) of osteosarcoma all occurring 9 to 13 years after treatment. These aren’t bad odds, but it’s worth noting events happened late so longer follow-up will be informative. TBL: The risk of secondary malignancy in the decade after radiosurgery for benign conditions is, in a word, tiny. | Wolf, Lancet Oncol 2018