The role of proton beam therapy in central neurocytoma: a single-institution experience

Publication date: Available online 16 February 2018
Source:Practical Radiation Oncology
Author(s): Kylie H. Kang, Emily Schapira, Andrzej Niemierko, Maria Martinez-Lage, Marc R. Bussière, Torunn I. Yock, Jay S. Loeffler, William E. Butler, Bob S. Carter, Helen A. Shih
PurposeCentral neurocytomas (CN) are rare WHO grade II tumors managed with surgery and radiation therapy. We report our experience in managing CN with proton beam therapy (PBT) when radiation therapy was employed.Methods and MaterialsWe identified 61 patients with pathologically-diagnosed CN treated at our institution between 1996-2016, of which 24 met inclusion criteria. Patient, tumor, and treatment characteristics are reported in context of progression-free survival and treatment-related adverse effects.ResultsOf 24 patients identified, median age at diagnosis was 21 years (range: 14 - 60). Median maximal tumor diameter was 4.5 cm (range: 1.4 - 6.8). Eighteen (75%) patients underwent upfront surgery alone. Sixteen (67%) patients received adjuvant or salvage PBT at a median dose of 54 Gy(RBE). Median follow-up was 56 months. Median progression-free survival (PFS) was 61 months. Eleven patients had disease progression with median time to progression of 22 months. Of the five patients with gross total resection, four experienced local recurrence and had MIB-1>4% (range: 4.5 - 30). There was improved PFS with addition of PBT to definitive surgery (log-rank, p=.06); there was no disease progression to date. In patients who experienced disease recurrence/progression, MIB-1<4% was associated with improved PFS (log-rank, p=.007). All patients tolerated PBT well with toxicities typical for cranial irradiation and with no grade ≥3 toxicities.ConclusionIn our cohort, CN with elevated MIB-1 index were at increased risk for disease progression. However, adjuvant radiotherapy appears to effectively prevent failure. PBT toxicities appear to be comparable if not less than published photon experiences.



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