Well-differentiated neurocytoma: What is the best available treatment?

Most neurocytomas are well differentiated, being associated with better long-term survival than the more aggressive atypical lesions. Atypical neurocytomas are characterized by an MIB-1 labeling index >3% or atypical histologic features. This analysis focuses on well-differentiated neurocytomas in order to define the optimal treatment. A case with a follow-up of 132 months is presented. The patient developed two recurrences two and four years after first surgery, each showing an increasing proliferation activity. Furthermore, all published well-differentiated neurocytoma cases were reviewed for surgery, radiotherapy, and prognosis. Additional relevant data were obtained from the authors. Complete resection (CTR), complete resection plus radiotherapy (CTR + RT), incomplete resection (ITR), and incomplete resection plus radiotherapy (ITR + RT) were compared for outcome by using the Kaplan-Meier method and the log-rank test. Data were complete in 301 patients (CTR, 108; CTR + RT, 27; ITR, 81; ITR + RT, 85). Local control and survival were better after CTR than after ITR (P < 0.0001 and P = 0.0085, respectively). Radiotherapy improved local control after ITR (P < 0.0001) and after CTR (P = 0.0474), but not survival (P = 0.17 and P = 1.0, respectively). In the ITR + RT group, doses less than or equal to54 Gy (n = 33) and >54 Gy (n = 32) were not significantly different for local control (P = 0.88) and survival (P = 0.95). The data demonstrated CTR to be superior to ITR for local control and survival. After CTR and ITR, radiotherapy improved local control, but not survival. A radiation dose of 54 Gy appeared sufficient. Application of postoperative radiotherapy should be decided individually, taking into account the risk of local failure, the need for another craniotomy, and potential radiation toxicity.