Artikel
Atypical meningioma: Progression-free survival of 161 cases with surgery only versus surgery and radiotherapy
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Veröffentlicht: | 9. Juni 2017 |
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Objective: Meningiomas are the most common primary tumors oft the central nervous system in adults, they account for 13-26% of all intracranial tumors. The majority of meningiomas are histologically classified as benign (World Health Organisation (WHO) grade I). However, 4.7-7.2% are defined as atypical meningioma, which recur frequently after total resection (Simpson grade I-II) and/or radiotherapy. Until now, the optimal adjuvant management is still unclear and controversial discussed. Recent retrospective studies analyzed the additional adjuvant radiotherapy with conflicting results. The purpose of this study was to evaluate whether the extent of surgery and receiving adjuvant radiotherapy after an initial operation along with other factors influenced the recurrence and survival rates of atypical meningioma.
Methods: Between February 2001 and March 2015, 161 cases of WHO grade II meningioma were operated in our Department of Neurosurgery. Among this population, 128 cases underwent surgical treatment alone and 33 cases underwent surgery and radiotherapy. Kaplan Meier analysis was used to provide median points estimates and time-specific rates. The ANOVA model was used in univariate and multivariate settings to identify significant factors associated with treatment. The hazard-ratio was calculated by Cox-regression model with a determined alpha-level of 5% and a statistical power of 80% (ß<0.2).
Results: The average age at the time of initial operation was 69 years, and the sex ratio (male/female) was 85/76. The mean follow-up period was 7.89 years. In a multivariate Cox-regression analysis, only Simpson grading was predictive of recurrence (hazard ratio = 1.8, p-value = 0.0004), Simpson grade I and II was associated with a longer progression-free survival compared to Simpson grade III and IV. Patients treated with surgery alone had a progression-free survival rate of 80% (3 years) and 72% (5 years), respectively, compared with 75% (3 years) and 63% (5 years) in patients treated with surgery and adjuvant radiotherapy. There was no statistically significant correlation between recurrence and subjecting patients to postoperative radiotherapy. Apart from Simpson grade I to II patients, the localization of meningioma in the anterior and posterior fossa was significantly associated with a longer progression-free survival (p<0.001).
Conclusion: The most important prognostic factor in determining recurrence was Simpson grading and the localization in the anterior and posterior fossa. Radiotherapy may not increase the progression-free survival after complete or incomplete resection.