Posted on: 05/14/2009
The infiltrative, diffuse pattern of recurrence in patients with malignant gliomas treated with bevacizumab.
L. Potthast, S. Chowdhary, E. Pan, D. Yu, W. Zhu, S. Brem; Moffitt Cancer Center, Tampa, FL
Background: There is no standard of care for recurrent gliomas; however, bevacizumab is often used as a salvage chemotherapy regimen. A diffuse, infiltrative pattern of recurrence, as evidenced by MR imaging, was seen manifesting as multifocal disease or presumed CSF dissemination with subependymal spread. Methods: We conducted a retrospective analysis of 40 recurrent glioma patients followed at Moffitt Cancer Center from September 2006 through December 2008 treated with bevacizumab alone or in combination with irinotecan. Histologies included glioblastoma (GB), anaplastic astrocytomas (AA), anaplastic oligodendrogliomas (AO), anaplastic oligoastrocytomas (AOA), and low-grade astrocytomas. Rate of diffuse, infiltrative recurrence, progression free survival (PFS) and overall survival (OS) were analyzed and correlated with respect to specific prognostic variables. Results: 38% (15) of the patients were female and 63% (25) were male. The median (range) age was 51 (20-72) years. The median (range) KPS was 80 (50-100). Twenty-six (65%) patients had GB, 8 (20%) AA, 2 (5%) AO, and 3 (8%) AOA and 1 (3%) had LGA. Five (13%) patients had a gross total resection (GTR), 23 (58%) a subtotal resection (STR) and 12 (30%) had biopsy only. The median (range) number of prior therapies was 2 (1-7). At time of analysis 28 (70%) patients had died. Incidence of diffuse, infiltrative recurrence was seen in 8 (20%) of patients (95% CI: [9%, 36%]). This recurrence seems to be negatively associated with age: rate for age<=50: 6/18 (33%); (95% CI: [13%, 59%]) while rate for age>50: 2/22 (9%); (95% CI: [1%, 29%]), with an odds ratio (OR) of 5.0. Conclusions: There appears to be an increase in a diffuse, infiltrative pattern of recurrence among recurrent glioma patients treated with bevacizumab as a salvage regimen. In our experience, this appears most prevalent in patients less than 50 years of age. It is unclear why the disparity among this subset of patients occurs, however, we hypothesize that this may once again highlight the distinct tumor biology among young glioma patients. The impact of this observation on clinical decision making on whether to utilize bevacizumab in young recurrent glioma patients warrants further investigation.
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