Histopathological features predictive of local control of atypical meningioma after surgery and adjuvant radiotherapy

• Published in: Journal of neurosurgery Vol. 130; no. 2; pp. 443 - 8
• Main Authors: Chen, William C, Magill, Stephen T, Wu, Ashley, Vasudevan, Harish N, Morin, Olivier, Aghi, Manish K, Theodosopoulos, Philip V, Perry, Arie, McDermott, Michael W, Sneed, Penny K, Braunstein, Steve E, Raleigh, David R
• Format: Journal Article
• Language: English
• Published: United States 01-02-2019
• Subjects: Aged; Brain Neoplasms - pathology; Brain Neoplasms - surgery; Brain Neoplasms - therapy; Cohort Studies; Female; Humans; Kaplan-Meier Estimate; Karnofsky Performance Status; Male; Meningioma - pathology; Meningioma - surgery; Meningioma - therapy; Middle Aged; Neoplasm Recurrence, Local; Neurosurgical Procedures - methods; Patient Selection; Predictive Value of Tests; Prognosis; Progression-Free Survival; Radiotherapy, Adjuvant - methods; Retrospective Studies; Risk Assessment; Salvage Therapy; Survival Analysis; IQR = interquartile range; STR = subtotal resection; RTOG = Radiation Therapy Oncology Group; EORTC = European Organization for Research and Treatment of Cancer; RPA = recursive partitioning analysis; GTR = gross-total resection; RT = radiotherapy; SRS = stereotactic radiosurgery; atypical meningioma; KPS = Karnofsky Performance Scale; oncology; MIB1; MVA = multivariate analysis; OS = overall survival; LI = labeling index; radiation; LFFR = local freedom from recurrence; radiotherapy; EBRT = external beam radiotherapy
• ISSN: 0022-3085; 1933-0693
• DOI: 10.3171/2017.9.jns171609

The goal of this study was to investigate the impact of adjuvant radiotherapy (RT) on local recurrence and
overall survival in patients undergoing primary resection of atypical meningioma, and to identify predictive factors to inform patient selection for adjuvant RT.
One hundred eighty-two patients who underwent primary resection of atypical meningioma at a single institution between 1993 and 2014 were retrospectively identified. Patient, meningioma, and treatment data were extracted from the medical record and compared using the Kaplan-Meier method, log-rank tests, multivariate analysis (MVA) Cox proportional hazards models with relative risk (RR), and recursive partitioning analysis.
The median patient age and imaging follow-up were 57 years (interquartile range [IQR] 45–67 years) and 4.4 years (IQR 1.8–7.5 years), respectively. Gross-total resection (GTR) was achieved in 114 cases (63%), and 42 patients (23%) received adjuvant RT. On MVA, prognostic factors for death from any cause included GTR (RR 0.4, 95% CI 0.1–0.9, p = 0.02) and MIB1 labeling index (LI) ≤ 7% (RR 0.4, 95% CI 0.1–0.9, p = 0.04). Prognostic factors on MVA for local progression included GTR (RR 0.2, 95% CI 0.1–0.5, p = 0.002), adjuvant RT (RR 0.2, 95% CI 0.1–0.4, p < 0.001), MIB1 LI ≤ 7% (RR 0.2, 95% CI 0.1–0.5, p < 0.001), and a remote history of prior cranial RT (RR 5.7, 95% CI 1.3–18.8, p = 0.03). After GTR, adjuvant RT (0 of 10 meningiomas recurred, p = 0.01) and MIB1 LI ≤ 7% (RR 0.1, 95% CI 0.003–0.3, p < 0.001) were predictive for local progression on MVA. After GTR, 2.2% of meningiomas with MIB1 LI ≤ 7% recurred (1 of 45), compared with 38% with MIB1 LI > 7% (13 of 34; p < 0.001). Recursive partitioning analysis confirmed the
existence of a cohort of patients at high risk of local progression after GTR without adjuvant RT, with MIB1 LI > 7%, and evidence of brain or bone invasion. After subtotal resection, adjuvant RT (RR 0.2, 95% CI 0.04–0.7, p = 0.009) and ≤ 5 mitoses per 10 hpf (RR 0.1, 95% CI 0.03–0.4, p = 0.002) were predictive on MVA for local progression.
Adjuvant RT improves local control of atypical meningioma irrespective of extent of resection. Although
independent validation is required, the authors’ results suggest that MIB1 LI, the number of mitoses per 10 hpf, and brain or bone invasion may be useful guides to the selection of patients who are most likely to benefit from adjuvant RT after resection of atypical meningioma.