Prospective, multicentric cohort study of surgery and radiotherapy with concomitant and adjuvant chemotherapy (temozolomide; TMZ) for patients with newly diagnosed and glioblastoma multiforme.

Abstract

e12534 Background: It is generally accepted that maximum resection is beneficial in patients with glioblastoma treated by adjuvant radiotherapy. However, reliable data on the value of cytoreductive surgery in conjunction with adjuvant concomitant radiochemotherapy are unavailable. It may be that concomitant radiochemotherapy abolishes the need for extensive surgical cytoreduction. We have therefore performed a cohort study of patients treated by surgery and concomitant radiochemotherapy with no or small residual tumor to test for differences in outcome. Methods: 180 patients with newly diagnosed and operated glioblastoma multforme, Karnofsky Performance Score ≥ 70 %, and early post-op. MRI (< 72 hours) demonstrating no or small residual contrast-enhancing tumor (< 1.5 cm) were planned for this prospective, multicenter cohort study. Primary aims were progression-free survival, secondary aims overall survival and safety. Results: Of 143 patients with evaluable early MRI and adjuvant concomitant temozomoide 75 patients had no residual tumor, 32 patients small residual tumor (0-1.5 cm diameter) and 59 patients larger residual tumor > 1.5 cm diameter (average 1.9 ± 1.2 cm), who did not fulfill the entry criteria regarding residual tumor diameter. PFS in patients with complete resection vs. small and larger residual tumors was 14.4 (16.0- 21.3) months, compared to 9.03 (3.04-15.0) and 5.33 (2.86-7.8, p < 0.0001). Median overall survival was not reached in patients with complete resections (95% CI: 21.4-25.9), as opposed to 16.9 (13.3-21.5) or 13.9 (10.3-17.5, p < 0.0001) months. Cox analysis demonstrated degree of resection (HR 1.84, p = 0.001) and age (1.03, p = 0.05) to be the only independent factors affecting survival. Conclusions: Even small residual contrast-enhancing tumor loads in patients with surgery for glioblastoma affect the efficacy of adjuvant concomitant radiochemotherapy in glioblastoma multiforme. Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Essex Pharma