髄膜腫術後に対する寡分割照射を用いた定位放射線治療の検討

Treatment outcome of stereotactic radiotherapy using the CyberKnife for meningioma

髄膜腫は，原発性脳腫瘍の約1/4を占める腫瘍で，一般的には良性腫瘍に分類される。World Health Organization（WHO）分類では，組織学的悪性度がグレードⅠからⅢに分けられており，大部分がグレードⅠに相当する。一方で，再発のリスクが高いグループとしてグレードⅡ/Ⅲが10％程度あることが知られており，これらの髄膜腫に関しては，局所制御に難渋することも多いとされる^1）。

In radiotherapy for meningioma, stereotactic radiosurgery or conventionally fractionated radiotherapy were mainly performed. We evaluated treatment outcomes of hypo-fractionated stereotactic radiotherapy followed by meningioma removal. Between October 2013 and December 2019, 24 lesions of meningioma（WHO grade Ⅰ/Ⅱ/Ⅲ＝11/12/1）received hypo-fractionated stereotactic radiotherapy using the CyberKnife after surgery. The mean radiation doses were 27Gy（range, 21-30Gy in 3-5 fractions）. Median follow-up time were 19 months. Two lesions of WHO grade Ⅱ meningioma and one lesion of WHO grade Ⅲ recurred locally（3, 24, and 21 months, respectively）. Although the follow-up time were inadequate, treatment outcomes of hypo-fractionated stereotactic radiotherapy were comparable to those of previous reports using stereotactic radiosurgery.