Defining Glioblastoma Resectability Through the Wisdom of the Crowd: A Proof-of-Principle Study

Adam M. Sonabend*, Brad E. Zacharia, Michael B. Cloney, Aarón Sonabend, Christopher Showers, Victoria Ebiana, Matthew Nazarian, Kristin R. Swanson, Anne Baldock, Henry Brem, Jeffrey N. Bruce, William Butler, Daniel P. Cahill, Bob Carter, Daniel A. Orringer, David W. Roberts, Oren Sagher, Nader Sanai, Theodore H. Schwartz, Daniel L. SilbergeldMichael B. Sisti, Reid C. Thompson, Allen E. Waziri, Guy McKhann

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


BACKGROUND:: Extent of resection (EOR) correlates with glioblastoma outcomes. Resectability and EOR depend on anatomical, clinical, and surgeon factors. Resectability likely influences outcome in and of itself, but an accurate measurement of resectability remains elusive. An understanding of resectability and the factors that influence it may provide a means to control a confounder in clinical trials and provide reference for decision making. OBJECTIVE:: To provide proof of concept of the use of the collective wisdom of experienced brain tumor surgeons in assessing glioblastoma resectability. METHODS:: We surveyed 13 academic tumor neurosurgeons nationwide to assess the resectability of newly diagnosed glioblastoma. Participants reviewed 20 cases, including digital imaging and communications in medicine-formatted pre- and postoperative magnetic resonance images and clinical vignettes. The selected cases involved a variety of anatomical locations and a range of EOR. Participants were asked about surgical goal, eg, gross total resection, subtotal resection (STR), or biopsy, and rationale for their decision. We calculated a “resectability index” for each lesion by pooling responses from all 13 surgeons. RESULTS:: Neurosurgeons’ individual surgical goals varied significantly (P = .015), but the resectability index calculated from the surgeons’ pooled responses was strongly correlated with the percentage of contrast-enhancing residual tumor (R = 0.817, P < .001). The collective STR goal predicted intraoperative decision of intentional STR documented on operative notes (P < .01) and nonresectable residual (P < .01), but not resectable residual. CONCLUSION:: In this pilot study, we demonstrate the feasibility of measuring the resectability of glioblastoma through crowdsourcing. This tool could be used to quantify resectability, a potential confounder in neuro-oncology clinical trials. ABBREVIATIONS:: AI, aggressiveness indexANOVA, analysis of varianceBx, biopsyDICOM, digital imaging and communications in medicineEOR, extent of resectionGBM, glioblastomaGTR, gross total resectionKPS, Karnofsky Performance ScaleMSM, motor-speech-middle cerebral arteryNIH score, National Institutes of Health Recurrent GBM ScoreRI, resectability indexSTR, subtotal resection

Original languageEnglish (US)
Pages (from-to)590-601
Number of pages12
Issue number4
StateAccepted/In press - Aug 4 2016

ASJC Scopus subject areas

  • Surgery
  • Clinical Neurology


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