Introduction: Glioblastoma (GBM) is the most common and malignant primary brain tumor, with a poor survival prognosis. Current GBM treatment calls for maximal safe resection with adjuvant chemoradiation or chemotherapy. Despite ongoing improvement with surgical technique, recurrence is inevitable. Diagnostic accuracy with recurrent GBM is difficult. To date, the gold standard comprises a second biopsy and histopathological analysis. However, not all patients undergo a second biopsy and its clinical benefit remains unclear. We aim to retrospectively examine and compare clinical outcomes in recurrent GBM patients who underwent a second biopsy at the time of recurrence to those who did not.

Methods: We reviewed the medical charts of patients undergoing craniotomy for GBM at our institution from March 2013 to April 2018. This study included 41 recurrent GBM patients whose outcomes of interest were reported. Demographic data, pre- and post-operative symptoms, tumor location, treatment modalities, Karnofsky Performance Score, extent of resection, and survival were among the extracted variables.

Results: For patients without a second biopsy after recurrence, the median survival from initial diagnosis was 20.15 months versus 56.5 months for those with a second biopsy (P = 0.007; HR = 0.3, 95% CI 0.12-0.76). The median survival from recurrence diagnosis was 4.25 months and 13.6 months for those without and with a second biopsy, respectively (P = 0.003; HR = 0.28, 95% CI 0.11-0.69).

Conclusion: Our retrospective study found greater median survival in patients that undergo a second biopsy compared to those who do not, following a recurrent GBM diagnosis.