Early necrosis following concurrent temozolomide and radiotherapy in adult patients with glioblastoma.

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Abstract No:

1513

Citation:

Journal of Clinical Oncology, 2006 ASCO Annual Meeting Proceedings Part I. Vol 24, No. 18S (June 20 Supplement), 2006: 1513

Author(s):

M. C. Chamberlain, M. J. Glantz, L. Chalmers, A. Van Horn, A. E. Sloan

Abstract:

Background: Concurrent temozolomide (TMZ) and radiotherapy (RT) is the new standard of care for patients with newly diagnosed glioblastoma GBM). This report is a prospective observational study of surgically confirmed early necrosis in adult patients with GBM treated with concurrent TMZ and RT and post-RT TMZ. Methods: 52 consecutive patients (33 males; 19 females) ages 34 to 69 years (median 60), with newly diagnosed GBM were treated with surgery (complete resection in 40%, incomplete in 33%, biopsy in 27%) followed by concurrent TMZ and RT (median tumor dose 60Gy) followed by planned 6 cycles of monthly TMZ. TMZ was administered as 75mg/m²/day for 42 consecutive days with radiotherapy followed by 200mg/m²/day for 5 consecutive days every 28 days. Neurological evaluations were performed monthly and cranial MR bimonthly. Results: 26 patients (50%) manifested clinical and neuroradiographic evidence of tumor progression within 6 months of completing RT. 15 patients (28%) underwent reoperation with image verified complete resection. Histopathology was interpreted as necrosis without evidence of tumor in seven patients (13%). Conclusion: The patients in this study with early necrosis suggest a potential and perhaps significant chemo- radiosensitization effect in a subset of patients treated with this regimen of concurrent TMZ and radiotherapy that may predict for durable responses and contribute to the regimens observed benefit in patients with newly diagnosed GBM. Clearly, confirmation of this preliminary observation of unexpected and common early necrosis using concurrent TMZ and radiotherapy in a larger GBM population is required.