Reoperation for recurrent glioblastoma multiforme

After maximal surgical resection and chemoradiation with temozolomide, glioblastoma (GBM) tumor progression occurs at a median of seven months. Repeat resection has been shown to be most beneficial for patients under the age of 50 with a Karnofsky performance status greater than 60, and tumor in non-eloquent cortex. In this selected subgroup of patients, quality of life can improve significantly with reoperation. Perfusion-based neuroimaging modalities are useful in establishing the diagnosis of GBM progression and can aid in differentiating active tumor from the treatment effects of chemotherapy and radiation. When surgery is undertaken, numerous retrospective studies have demonstrated that greater extent of resection leads to increased survival, similar to the relationship seen in newly diagnosed GBM. Meaningful benefit most reliably occurs with an extent of resection greater than 80% or postoperative residual tumor volume less than 3 cm3; however, this should be balanced with the fact that new or worsened postoperative neurological deficits can shorten survival by three to four months. Surgeons should therefore employ functional imaging and intraoperative functional testing to minimize the risk of incurring new deficits when working near eloquent brain regions. Though not yet adequately studied in recurrent GBM, 5-aminolevulinic acid fluorescence-guided microsurgical resection and intraoperative magnetic resonance imaging may be useful surgical adjuncts. Patients with recurrent GBM should be considered for enrolment in clinical trials and tumor banking to identify new treatment strategies and enhance our understanding of the biology of treatment resistance.