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Inter-institutional variance of
postoperative radiotherapy and follow up for meningiomas in Germany.
Impact of changes of the WHO classification
Simon M, Bostrom J, Koch P, Schramm J
Neurochirurgische Klinik, Universitatsklinikum Bonn, Germany.
Objective. To document and critically analyze the impact
of the revised WHO 2000 histological classification for meningiomas on
indications for postoperative radiotherapy/radiosurgery and MRI
follow-up protocols.
Methods. The current
(2000) WHO classification was used to grade 57 meningiomas operated at
our institution, which had previously been reviewed in 1999.
All German Neurosurgical
Departments performing intracranial microsurgery were asked to detail
their guidelines for radiation therapy and follow-up for meningiomas
of different WHO grades.
Results. Use of the
current criteria downgraded 7/15 (47%) atypical (WHO grade II, MII)
meningiomas to grade I (MI), and 4/6 (67%) anaplastic (WHO grade III,
MIII) tumors to grade II.
Indications for
radiotherapy/radiosurgery and MRI follow-up protocols varied
substantially with the histological grade and between
institutions.
E.g. after an incomplete resection,
radiotherapy/radiosurgery recommendations differed between MI and MII
in 30/58 (52%), and between MII and MIII in 34/56 (61%) units.
Conclusions. Correlative
studies combining treatment and outcome data with a standardized
histopathological analysis are warranted to properly define
indications for radiotherapy/radiosurgery and follow-up protocols
after surgery for meningiomas of different histological grades.
The use of changing grading
paradigms during recent years renders decision making based on local
and published experience difficult.
The relatively high number of
meningiomas classified as atypical/WHO grade II in current practice
would argue against an uncritically aggressive approach to these
tumors.
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