In:
Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 25, No. 18_suppl ( 2007-06-20), p. 2044-2044
Abstract:
2044 Background: Irradiation remains the cornerstone of management for glioblastoma multiforme (GBM). Guidelines adopted by the RTOG and EORTC advocate encompassing the primary tumor (sometimes with edema), and a 2 cm margin in the high dose volume. These recommendations have emerged from imaging studies and post-mortem analyses. A shortcoming of this approach is the exposure of critical structures (e.g. optic apparatus) to doses of radiation that may exceed organ tolerance. We sought to determine whether the temporal bone (rather than the aforementioned 2 cm radius) serves as a barrier to tumor spread when regarded as the anterior margin for temporal lobe lesions. We hypothesized that toxicity could be reduced without compromising tumor control. Methods: During the period 2003–2006, 250 patients with GBM were treated with surgery and primary irradiation at our institution. Chemotherapy (e.g., Stupp regimen) was given to approximately one-third of patients. 31 patients had lesions confined to the temporal lobe. All patients had MRI at baseline and at monthly intervals following a course of 60 Gy delivered by conformal techniques. The Clinical Target Volume included the primary lesion, the edema when present and a 2 cm margin except in the direction of the temporal bone. At follow-up (median = 10 months), patients were judged to have stable disease, local progression (i.e. failure within the temporal lobe), distant progression (i.e., brain failure beyond the temporal lobe) or combinations of the latter 2. Results: 11 patients have remained with stable disease. 17 have failed locally. 3 have manifested distant failure. Of the latter, only one patient failed in the infratemporal fossa. Conclusions: An acceptable level of recurrence (e.g., 〈 5% beyond the temporal bone) is seen when the temporal bone, rather than a 2 cm margin is employed as the anterior border of the CTV. As GBM patients live longer in the era of combined modality therapy, a greater opportunity will exist to express radiation damage. The strategy proposed herein provides tumor control while respecting optic tolerance without resorting to complex, expensive approaches such as IMRT. No significant financial relationships to disclose.
Type of Medium:
Online Resource
ISSN:
0732-183X
,
1527-7755
DOI:
10.1200/jco.2007.25.18_suppl.2044
Language:
English
Publisher:
American Society of Clinical Oncology (ASCO)
Publication Date:
2007
detail.hit.zdb_id:
2005181-5
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