Prognostic value of detecting recurrent glioblastoma multiforme in surgical specimens from patients after radiotherapy: should pathology evaluation alter treatment decisions?

Tihan, Tarik; Barletta, Justine; Parney, Ian; Lamborn, Kathleen; Sneed, Penny K.; Chang, Susan

doi:10.1016/j.humpath.2005.11.010

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Volume 37, Issue 3 , Pages 272-282, March 2006

Prognostic value of detecting recurrent glioblastoma multiforme in surgical specimens from patients after radiotherapy: should pathology evaluation alter treatment decisions?

Tarik Tihan, MD, PhD
- Department of Pathology, University of California at San Francisco, San Francisco, CA 94143-0511, USA
- Corresponding author. Department of Pathology, University of California at San Francisco Medical Center, San Francisco, CA 94143-0511, USA.
Justine Barletta, MD
- Department of Pathology, University of California at San Francisco, San Francisco, CA 94143-0511, USA
Ian Parney, MD
- Department of Neurological Surgery, University of California at San Francisco, San Francisco, CA 94143-0511, USA
Kathleen Lamborn, PhD
- Department of Neurological Surgery, University of California at San Francisco, San Francisco, CA 94143-0511, USA
Penny K. Sneed, MD
- Department of Radiation Oncology, University of California at San Francisco, San Francisco, CA 94143-0511, USA
Susan Chang, MD
- Department of Neurological Surgery, University of California at San Francisco, San Francisco, CA 94143-0511, USA

Received 12 September 2005; received in revised form 16 November 2005; accepted 18 November 2005. published online 23 January 2006.

Summary

The prognostic significance of the histologic type and grade of gliomas at initial surgery is well established, but the value of histologic findings in resections after radiotherapy is unclear. Despite this uncertainty, pathologic interpretation of specimens after radiotherapy influences immediate treatment decisions. It is important to determine if, and to what extent, treatment decisions should be based on this information. We aimed to determine the prognostic value of pathologic evaluation in postradiation specimens from 54 patients with similar clinical features who underwent a second surgery for the treatment of radiologic worsening after external beam radiotherapy. We categorized the specimens from the second surgery as either recurrent tumor (category 1) or radionecrosis (category 2). Patients in category 1 had actively proliferating neoplasms with classical features of glioblastoma, whereas patients in category 2 had no evidence of tumor in their surgical specimens. Cases in which a clear-cut definition could not be made were labeled indeterminate (category 3). Despite the morphological evidence of tumor, there were no significant differences between categories 1 and 2 in any of the survival parameters tested. The only difference between groups was higher frequency of iodine 125 (¹²⁵I) placement at second surgery in category 1 patients (P < .028). Patients in category 1 with or without ¹²⁵I treatment had similar survival characteristics. We conclude that histopathologic evaluation of postradiotherapy specimens was not helpful in predicting outcome or dictating further management. A comprehensive prospective study with advanced radiologic, pathologic, and molecular analyses may be more useful to determine prognostically valuable parameters.

Keywords: Glioblastoma multiforme, Malignant glioma, Postradiotherapy, Prognosis, Radionecrosis, Radiotherapy, Recurrent glioblastoma