LAUSR

AbstractThe available evidence suggests that the clinical benefits of extended surgical resection are limited for chemo-sensitive tumors, such as primary central nervous system lymphoma (PCNSL). Oligodendroglioma is generally thought to be more sensitive to chemotherapy than astrocytoma of ­comparable grades. Here, we compare the survival benefit of gross total resection (GTR) in oligodendroglioma patients relative to astrocytoma patients. Using the Surveillance, Epidemiology, and End Results Program (SEER) database, we identified 2,378 WHO grade II oligodendroglioma patients (O2) and 1,028 WHO grade III oligodendroglioma patients (O3). Surgical resection was defined as GTR, subtotal resection (STR), biopsy only, or no resection. Kaplan-Meier and multivariate Cox regression survival analysis were used to assess survival with respect to extent of resection (EOR). Cox multivariate analysis revealed that the hazard of dying from O2 and O3 was comparable between patients who underwent biopsy only (or STR) and GTR (O2: HR 1.06, 95% CI 0.73–1.53; O3: HR 1.18, 95% CI 0.80–1.72). A comprehensive search of the published literature identified eight articles without compelling evidence that GTR is associated with improved overall survival in oligodendroglioma patients. In contrast, we found that patients afflicted with WHO grade II astrocytoma (A2) benefited significantly from GTR. We identified 4,113 A2 patients in the SEER. A multivariate Cox survival analysis indicated that relative to A2 patients who underwent STR, A2 patients who underwent a GTR showed a 28.3% reduction in the hazard of death. Similar risk reductions were observed in both A2 patients age 4 years, a finding reminiscent of anaplastic astrocytoma patients. In contrast, for A2 patients age ≥ 50, the GTR associated survival benefit was approximately 6 months, resembling that observed in glioblastoma patients. Relative to A2 patients, patients afflicted with WHO grade III astrocytoma (anaplastic astrocytoma or A3) derived greater survival benefit from GTR. We identified 2,755 A3 patients in SEER. The hazard of dying from the A3 was reduced in GTR patients by 40% relative to STR patients. For comparison, the hazard of dying from the glioblastoma was reduced in GTR patients by 24% relative to STR patients. We observed that age <50 and post-TMZ (2005–2010) independently associated with an improved survival benefit for A3 who underwent GTR. The median survival of AA patients age<50 who underwent GTR and STR in the post-TMZ era was not reached for the GTR population and 52 months for the STR population, respectively. For glioblastoma patients, the corresponding numbers for median survival were 21 and 18 months.