An Extent of Resection Threshold for Recurrent GlioblastomasKeywords: recurrent disease, resection, glioblastoma multiforme, surgery, outcomeInteractive Manuscript
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What is the background behind your study?
For newly-diagnosed glioblastoma patients, mounting evidence suggests that greater extent of resection (EOR) corresponds to better overall survival.
What is the purpose of your study?
For patients with recurrent glioblastoma, however, the value of a second resection at the time of recurrence remains uncertain. Specifically, what proportion of contrast-enhancing recurrent glioblastoma tissue must be removed to improve overall survival and what is the survival benefit beyond this threshold?
Describe your patient group.
All 170 patients previously underwent resection and adjuvant therapy for a de novo glioblastoma.
Describe what you did.
We identified 170 consecutive, recurrent glioblastoma patients treated at the Barrow Neurological Institute from 2001-2011. Clinical and radiographic data were collected retrospectively, including volumetric tumor analysis.
Describe your main findings.
Median clinical follow-up was 22.6 months and no patient was unaccounted. At the time of recurrence, the median preoperative tumor volume was 26.1 cm3. Following re-resection, median postoperative tumor volume was 3.1 cm3, equating to an 87.4% EOR. The median overall survival was 19.0 months, with a median progression-free survival following re-resection of 5.2 months. Using Cox proportional hazards analysis, age, KPS, and EOR were predictive of survival following repeat resection (p=0.0001). A significant survival advantage was seen with as little as 80% EOR. Recursive partitioning analysis validated these findings and provided additional stratification parameters related to age, extent of resection, and tumor burden.
Describe the main limitation of this study.
This is a retrospective study.
Describe your main conclusion.
For recurrent glioblastomas, improvement in overall survival can be attained beyond an 80% extent of resection.
Describe the importance of your findings and how they can be used by others.
Interestingly, this lower-limit closely approximates the 78% threshold reported for newly-diagnosed glioblastomas, suggesting that, for a subset of patients, the value of microsurgical resection does not diminish despite biological progression.
For newly-diagnosed glioblastoma patients, mounting evidence suggests that greater extent of resection (EOR) corresponds to better overall survival.
For patients with recurrent glioblastoma, however, the value of a second resection at the time of recurrence remains uncertain. Specifically, what proportion of contrast-enhancing recurrent glioblastoma tissue must be removed to improve overall survival and what is the survival benefit beyond this threshold?
All 170 patients previously underwent resection and adjuvant therapy for a de novo glioblastoma.
We identified 170 consecutive, recurrent glioblastoma patients treated at the Barrow Neurological Institute from 2001-2011. Clinical and radiographic data were collected retrospectively, including volumetric tumor analysis.
Median clinical follow-up was 22.6 months and no patient was unaccounted. At the time of recurrence, the median preoperative tumor volume was 26.1 cm3. Following re-resection, median postoperative tumor volume was 3.1 cm3, equating to an 87.4% EOR. The median overall survival was 19.0 months, with a median progression-free survival following re-resection of 5.2 months. Using Cox proportional hazards analysis, age, KPS, and EOR were predictive of survival following repeat resection (p=0.0001). A significant survival advantage was seen with as little as 80% EOR. Recursive partitioning analysis validated these findings and provided additional stratification parameters related to age, extent of resection, and tumor burden.
This is a retrospective study.
For recurrent glioblastomas, improvement in overall survival can be attained beyond an 80% extent of resection.
Interestingly, this lower-limit closely approximates the 78% threshold reported for newly-diagnosed glioblastomas, suggesting that, for a subset of patients, the value of microsurgical resection does not diminish despite biological progression.
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