Clinical Outcome and Prognostic Factors for Central Neurocytoma

Abstract

Central neurocytomas are intraventricular neoplasms of the central nervous system that comprise 0.25-0.5% of brain tumors and their optimal management remains controversial due to their rarity. We assessed clinical outcome for a historical cohort of neurocytoma patients and evaluated effects of tumor atypia, tumor size, extent of resection (EOR), and adjuvant radiation (RT). Progression-free survival (PFS) was measured from date of first surgical resection. Differences in PFS were measured by Kaplan-Meier and proportional hazard ratio methods. Tumor atypia was defined as MIB-1 index >2%, focal necrosis, or microvascular proliferation, as previously established. A total of 22 patients (14 males, 8 females) were treated between 1995 and 2009, with a median age at diagnosis of 24 years (range 11-62). A total of 8 patients experienced recurrent/progressive disease. Median follow-up by MRI was 38 month (range 0.1-183) for those who have not progressed. Overall 3-yr PFS was 70% (CI 41-86%). Only three patients died and all had atypical tumors. For the remaining patients, median follow-up for survival was 51 month (range 0.1-183). We examined effects of tumor atypia and MIB-1 labeling. Ten of 22 tumors had atypical features. There was near 100% concordance between tumor atypia and MIB-1 labeling: only 1 tumor was atypical based on microvascular proliferation but had MIB-1 ≤ 2%. Three-year PFS was 78% for MIB labeling ≤ 2% and 39% for MIB labeling >2% (HR 7.7, CI 2 - 40, p = 0.016). Median tumor diameter was 4.3 cm (range 0.8-8.6 cm). Three-yr PFS was 48% (CI 21-77%) for tumor >4.3 cm and 74.1% (CI 29-93%) for tumor ≤4.3 cm (HR 1.6, CI 0.5 - 6.6, p = 0.49). We examined influence of EOR and adjuvant RT. Five patients had gross total resection (GTR), and 17 had subtotal resection (STR). No patient had a biopsy only. Seven patients progressed after STR, and one patient recurred after GTR. None of the GTR patients received adjuvant RT and four of the STR patients received adjuvant RT. Three-year PFS rates by extent of resection and adjuvant RT are shown (in table below). For patients with central neurocytoma, MIB-1 labeling index >2% significantly predicts worse outcome. The additional criteria for tumor atypia did not add useful prognostic information. Although patient numbers are too small for conclusive confirmation, our data indicate that lesser EOR and larger tumors size may confer worse prognosis and adjuvant RT after STR may improve PFS.Tabled 13-yr PFS Rates by Extent of Resection and Adjuvant RTGTR/No RT (5 pts)STR/All (17 pts)STR/No RT (13 pt)STR/RT (4 pts)3-yr PFS (%) (CI)80% (CI 20-97%)63% (CI 32-83%)48% (CI 16-74%)67% (CI 5-95%) Open table in a new tab