Maximize surgical resection beyond contrast-enhancing boundaries in newly diagnosed glioblastoma multiforme: is it useful and safe? A single institution retrospective experience

The extent of surgical resection (EOR) has been recorded as conditioning outcome in glioblastoma multiforme (GBM) patients but no significant improvements were recorded in survival. The study aimed to evaluate the impact of EOR on survival, investigating the role of fluid-attenuated inversion recovery (FLAIR) abnormalities removal. 282 newly diagnosed GBM patients were treated with surgery followed by concurrent and adjuvant chemo-radiotherapy. The EOR was defined as: SUPr, in case of resection amounting to 100% of enhanced and FLAIR areas; gross total (GTR) in case of resection between 90 and 100% of enhanced areas with variable amount of FLAIR abnormalities; sub-total (STR), between 10 and 89%; biopsy (B) < 10%. FLAIR-RTV was dichotomized in percentage values to identify the best separation threshold for progression free survival (PFS) and overall survival (OS). SUPr was obtained in 21 patients (7.4%), GTR in 60 (21.3%), STR in 143 (50.7%) and biopsy only in 58 (20.6%). The median, 1, 2-year PFS were 10.4 +/- 0.4 months, 39.0 +/- 3.0, and 17.0 +/- 2.0%; the median, 1, 2-year OS were 14.5 +/- 0.5 months, 63.3 +/- 3.0, and 23.1 +/- 3.1%. EOR was significantly influencing survival (p < 0.001). The median, 1, 2-year OS were 28.6 +/- 5.2 months, 90.0 +/- 6.0, 71.0 +/- 10.0% for patients underwent SUPr vs. 16.2 +/- 1.2 months, 81.0 +/- 5.0, 24.0 +/- 6.0% for GTR. The FLAIR removal threshold conditioning survival was 45%. Minor complications were recorded in 14 (5%) patients and major in 8 (2.8%). surgical resection beyond contrast-enhancing boundaries could represent a promising strategy to improve outcome in GBM patients. The identification of a FLAIR-RTV threshold can be useful in clinical practice and it was recorded as factor influencing survival.