Clinical outcome and prognostic factors for central neurocytoma: twenty year institutional experience

Abstract

Central neurocytomas are uncommon intraventricular neoplasms whose optimal management remains controversial due to their rarity. We assessed outcomes for a historical cohort of neurocytoma patients and evaluated effects of tumor atypia, size, resection extent, and adjuvant radiotherapy. Progression-free survival (PFS) was measured by Kaplan-Meier and Cox proportional hazards methods. A total of 28 patients (15 males, 13 females) were treated between 1995 and 2014, with a median age at diagnosis of 26 years (range 5-61). Median follow-up was 62.2 months and 3 patients were lost to follow-up postoperatively. Thirteen patients experienced recurrent/progressive disease and 2-year PFS was 75% (95% CI 53-88%). Two-year PFS was 48% for MIB-1 labeling >4% versus 90% for ≤4% (HR 5.4, CI 2.2-27.8, p = 0.0026). Nine patients (32%) had gross total resections (GTR) and 19 (68%) had subtotal resections (STR). PFS for >80% resection was 83 versus 67% for ≤80% resection (HR 0.67, CI 0.23-2.0, p = 0.47). Three STR patients (16%) received adjuvant radiation which significantly improved overall PFS (p = 0.049). Estimated 5-year PFS was 67% for STR with radiotherapy versus 53% for STR without radiotherapy. Salvage therapy regimens were diverse and resulted in stable disease for 54% of patients and additional progression for 38 %. Two patients with neuropathology-confirmed atypical neurocytomas died at 4.3 and 113.4 months after initial surgery. For central neurocytomas, MIB-1 labeling index >4% is predictive of poorer outcome and our data suggest that adjuvant radiotherapy after STR may improve PFS. Most patients requiring salvage therapy will be stabilized and multiple modalities can be effectively utilized.

Fig. 1

Representative neurocytoma MRI imaging findings. a T2 weighted imaging of a 44-year-old male found to have an 8.6 × 7.2 cm heterogeneous right lateral ventricle mass; predominantly isointense on T2 weighted imaging with no significant enhancement on post-contrast series. b T2 FLAIR imaging of a 23-year-old male found to have a heterogeneous lobulated mass with a mildly enhancing component and other non-enhancing components extending superiorly from the suprasellar cistern. c T2 FLAIR imaging of a 20-year-old female found to have a 3.4 × 2.5 cm highly cellular lobulated nonenhancing intraventricular mass attached to the anterior portion of the septum pellucidum

Fig. 2

PFS based on tumor and clinical characteristics. a Two-year PFS was 82 % for tumors >4.1 cm versus 75 % for tumors ≤4.1 cm, with a hazard ratio of 1.2 (CI 0.37–3.6, p = 0.80). b Two-year PFS was 83 % for >80 % resection and 67 % for ≤80 % resection, with a hazard ratio of 0.67 (CI 0.23–2.0, p = 0.47). c Two-year PFS was 90 % for MIB-1 labeling ≤4 and 48 % for MIB-1 labeling >4 %, with a hazard ratio of 0.18, (CI 0.036–0.44, p = 0.0026). d Two-year PFS was 100 % for patients with STR plus adjuvant radiation versus 70 % for patients who underwent STR but did not undergo post-op radiation, with an undefined hazard ratio since we did not achieve events in greater than 50 % of relevant patients. However, the addition of adjuvant radiation significantly improved overall PFS (p = 0.049)