The butterfly effect on glioblastoma: is volumetric extent of resection more effective than biopsy for these tumors?

A subset of patients with glioblastoma (GBM) have butterfly GBM (bGBM) that involve both cerebral hemispheres by crossing the corpus callosum. The prognoses, as well as the effectiveness of surgery and adjuvant therapy, are unclear because studies are few and limited. The goals of this study were to: (1) determine if bGBM have worse outcomes than patients with non-bGBM, (2) determine if surgery is more effective than biopsy, and (3) identify factors independently associated with improved outcomes for these patients. Adult patients who underwent surgery for a newly diagnosed primary GBM at an academic tertiary-care institution between 2007 and 2012 were retrospectively reviewed and tumors were volumetrically measured. Of the 336 patients with newly diagnosed GBM who were operated on, 48 (14 %) presented with bGBM, where 29 (60 %) and 19 (40 %) underwent surgical resection and biopsy, respectively. In multivariate analysis, a bGBM was independently associated with poorer survival [HR (95 % CI) 1.848 (1.250-2.685), p < 0.003]. In matched-pair analysis, patients who underwent surgical resection had improved median survival than biopsy patients (7.0 vs. 3.5 months, p = 0.03). In multivariate analysis, increasing percent resection [HR (95 % CI) 0.987 (0.977-0.997), p = 0.01], radiation [HR (95 % CI) 0.431 (0.225-0.812), p = 0.009], and temozolomide [HR (95 % CI) 0.413 (0.212-0. 784), p = 0.007] were each independently associated with prolonged survival among patients with bGBM. This present study shows that while patients with bGBM have poorer prognoses compared to non-bGBM, these patients can also benefit from aggressive treatments including debulking surgery, maximal safe surgical resection, temozolomide chemotherapy, and radiation therapy.