Abstract and Introduction
Abstract
Objective: Stereotactic radiosurgery (SRS) and stereotactic radiotherapy (SRT) have been used as a primary treatment or adjuvant to resection in the management of intracranial meningiomas (ICMs). The aim of this analysis is to compare the safety and long-term efficacy of SRS and SRT in patients with primary or recurrent ICMs.
Methods: A systematic review of the literature comparing SRT and SRS in the same study was conducted using PubMed, the Cochrane Library, Google Scholar, and EMBASE from January 1980 to December 2018. Randomized controlled trials, case-control studies, and cohort studies (prospective and retrospective) analyzing SRS versus SRT for the treatment of ICMs in adult patients (age > 16 years) were included. Pooled and subgroup analyses were based on the fixed-effect model.
Results: A total of 1736 patients from 12 retrospective studies were included. The treatment modality used was: 1) SRS (n = 306), including Gamma Knife surgery (n = 36), linear accelerator (n = 261), and CyberKnife (n = 9); or 2) SRT (n = 1430), including hypofractionated SRT (hFSRT, n = 268) and full-fractionated SRT (FSRT, n = 1162). The median age of patients at the time of treatment was 59 years. The median follow-up duration after treatment was 35.5 months. The median tumor volumes at the time of treatment with SRS, hFSRT, and FSRT were 2.84 cm3, 5.45 cm3, and 12.75 cm3, respectively. The radiographic tumor control at last follow-up was significantly worse in patients who underwent SRS than SRT (odds ratio [OR] 0.47, 95% confidence interval [CI] 0.27–0.82, p = 0.007) with 7% less volume of tumor shrinkage (OR 0.93, 95% CI 0.61–1.40, p = 0.72). Compared to SRS, the radiographic tumor control was better achieved by FSRT (OR 0.46, 95% CI 0.26–0.80, p = 0.006) than by hFSRT (OR 0.81, 95% CI 0.21–3.17, p = 0.76). Moreover, SRS leads to a significantly higher risk of clinical neurological worsening during follow-up (OR 2.07, 95% CI 1.06–4.06, p = 0.03) and of immediate symptomatic edema (OR 4.58, 95% CI 1.67–12.56, p = 0.003) with respect to SRT. SRT could produce a better progression-free survival at 4–10 years compared to SRS, but this was not statistically significant (p = 0.29).
Conclusions: SRS and SRT are both safe options in the management of ICMs. However, SRT carries a better radiographic tumor control rate and a lower incidence of posttreatment symptomatic worsening and symptomatic edema, with respect to SRS. However, further prospective studies are still needed to validate these results.
Introduction
INTRACRANIAL meningioma (ICM) constitutes 33.8% of all brain tumors and is almost always histologically benign (95%).[44] Atypical ICMs comprise 5%–15% and the malignant variety encompasses 1%–3% of meningiomas,[35] and is associated with a higher risk of tumor recurrence after surgery than benign meningioma.[44] Gross-total resection (GTR) using a microsurgical technique is the treatment of choice for easily accessible meningiomas.[41,43] However, meningiomas adjacent to, or abutting, critical neural or vascular structures, such as skull base meningiomas, carry a significant risk of morbidity and mortality if GTR is pursued.[27] Stereotactic radiotherapy (SRT) and stereotactic radiosurgery (SRS) have emerged as highly effective alternatives or as complements to resection. SRS and SRT have been used as primary therapy for benign meningioma, especially when located closer to critical areas, as well as for adjuvant treatment for residual or recurrent tumors.[29,38] SRS carries a 5-year tumor control rate similar to GTR, with lower morbidity than surgery, especially for skull base lesions.[1] Moreover, adjuvant radiation treatment of meningiomas initially treated with subtotal resection (STR) results in a tumor control rate equivalent to GTR.[34] Radiation can be delivered using different techniques that are grouped into two categories, namely SRT and SRS. SRS includes one to a maximum of five sessions of Gamma Knife surgery (GKS),[28] linear accelerator (LINAC) treatment,[22,42] and CyberKnife,[26] while SRT includes multisession hypofractionated SRT (hFSRT) and full-fractionated SRT (FSRT).[8,18] However, there is no consensus on what is the best technique to treat ICMs.[25] We conducted a systematic review and meta-analysis including randomized-controlled trials (RCTs), case-control studies, and cohort studies (retrospective or prospective) comparing the clinical and radiological outcomes of adult patients with ICMs treated with SRS versus SRT.
Neurosurg Focus. 2019;46(6):e2 © 2019 American Association of Neurological Surgeons
