A study of prognostic factors in 45 cases of atypical meningioma

Toshiki Endo, Ayumi Narisawa, Hosam Shata Mohamed Ali, Kensuke Murakami, Takashi Watanabe, Mika Watanabe, Hidefumi Jokura, Hidenori Endo, Miki Fujimura, Yukihiko Sonoda, Teiji Tominaga

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43 Citations (Scopus)


Background: Atypical meningioma differs from Grade I meningioma in terms of high recurrence rate and short life expectancy. We evaluated the clinical course of atypical meningioma and investigated prognostic factors affecting its outcomes. Method: We reviewed 45 patients with atypical meningioma who underwent surgical intervention between January 2000 and December 2013. The mean age of the patients and mean follow-up period was 58.7 years and 81.0 months, respectively. Analyses included factors such as patient age, gender, location and size of tumor, extent of surgical resection (Simpson Grading System), and MIB-1 labeling index (LI). Univariate analysis was used to detect prognostic factors associated with recurrence and survival. Results: The 5-year recurrence-free rate for all 45 patients was 58.4 %; 5- and 10-year survival rates were 83.2 % and 79.9 %, respectively. In univariate analyses, age >60 years, and MIB-1 LI correlated with disease recurrence, whereas age >60 years, subtotal surgical resection, MIB-1 LI, and indication for radiotherapy correlated with death. MIB-1 LI levels higher than 12.8 % and 19.7 % predicted recurrence and death, respectively. In our cohort, 26 patients received postoperative radiotherapy including conventional radiation (n = 21) or gamma knife radiosurgery (n = 5). Postoperative radiotherapy did not decrease recurrence rates in our cohort (p = 0.63). Six and two patients who died during the study period underwent conventional radiation and radiosurgery, respectively. Conclusions: Age, male gender, extent of surgical resection, and higher MIB-1 LI influenced the outcome of atypical meningioma. In our cohort, postoperative radiotherapy failed to provide long-term tumor control. Following incomplete surgical resection of atypical meningioma in elderly patients, adjuvant postoperative radiotherapy may not be an ideal treatment option, particularly when MIB-1 LI is higher than 19.7 %.

Original languageEnglish
Pages (from-to)1661-1667
Number of pages7
JournalActa Neurochirurgica
Issue number9
Publication statusPublished - 2016 Sept 1


  • Atypical meningioma
  • Cranial base
  • MIB-1 LI
  • Prognostic factor
  • Recurrence


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