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A
randomized trial on dose-response in radiation therapy of low-grade
cerebral glioma: European Organization for Research and Treatment of
Cancer (EORTC) Study 22844
Karim
AB, Maat B, Hatlevoll R, Menten J, Rutten EH, Thomas DG, Mascarenhas
F, Horiot JC, Parvinen LM, van Reijn M, Jager JJ, Fabrini MG, van
Alphen AM, Hamers HP, Gaspar L, Noordman E, Pierart M, van Glabbeke M
Department of Radiation Oncology, Free University Hospital,
Amsterdam, The Netherlands. radiother@azvu.nl
Purpose.
Cerebral low-grade gliomas (LGG) in adults are mostly composed of
astrocytomas, oligodendrogliomas, and mixed oligoastrocytomas.
There
is at present no consensus in the policy of treatment of these
tumors.
We
sought to determine the efficacy of radiotherapy and the presence of a
dose-response relationship for these tumors in two multicentric
randomized trials conducted by the European Organization for Research
and Treatment of Cancer (EORTC).
The
dose-response study is the subject of this article.
Methods
and Materials.
For the dose-response trial, 379 adult patients with cerebral LGGs
were randomized centrally at the EORTC Data Center to receive
irradiation postoperatively (or postbiopsy) with either 45 Gy in 5
weeks or 59.4 Gy in 6.6 weeks with quality-controlled radiation
therapy.
All
known parameters with possible influences on prognosis were
prospectively recorded.
Conventional
treatment techniques were recommended.
Results.
With 343 (91%) eligible and evaluable patients followed up for at
least 50 months with a median of 74 months, there is no significant
difference in terms of survival (58% for the low-dose arm and 59% for
the high-dose arm) or the progression free survival (47% and 50%)
between the two arms of the trial.
However,
this prospective trial has revealed some important facets about the
prognostic parameters: The T of the TNM classifications as proposed in
the protocol appears to be one of the most important prognostic
factors (p < 0.0001) on multivariate analysis.
Other
prognostic factors, most of which are known, have now been quantified
and confirmed in this prospective study.
Conclusion.
The EORTC trial 22844 has not revealed the presence of
radiotherapeutic dose-response for patients with LGG for the two dose
levels investigated with this conventional setup, but objective
prognostic parameters are recognized.
The
tumor size or T parameter as used in this study appears to be a very
important factor.
PMID:
8948338 [PubMed - indexed for MEDLINE]
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