Patterns Of Care And Outcomes Analysis For Adult Patients With Newly Diagnosed Medulloblastoma: A 30-Year Single Institution Experience

Abstract

Medulloblastoma in the adult population is a rare disease with limited data regarding patient prognosis and appropriate course of treatment. A recent NCDB analysis correlated adjuvant chemoradiation to improved overall survival (OS). We performed a study of adult (age ≥18 years old) medulloblastoma patients to better understand outcomes and prognostic factors. An IRB approved chart review of adult medulloblastoma patients treated at our institution with 6-month minimum follow-up was conducted. We collected patient, disease, and treatment characteristics and outcomes including OS, progression-free survival (PFS), local control (LC), and freedom from distant metastasis (FDM). Uni- and multivariable survival analyses were performed using Cox regression model. OS was estimated using Kaplan-Meier (KM) test methods. Statistical analysis was performed with JMP version 15.0 software with statistical significance established for p-values < 0.05. Thirty-two patients were treated (1992-2018) with postoperative radiotherapy (RT) including tumor bed/posterior fossa (median dose: 3600 cGy/20 fractions) and craniospinal irradiation (median dose: 2340 cGy/13 fractions) either alone (n = 10; 31%) or with adjuvant chemotherapy (aCTH: n = 22; 69%); of whom only 40% were known to complete the full aCTH course. Male patients demonstrated worse OS, PFS, FDM, and LC compared to their female counterparts. Univariable analysis showed sex, tumor location (lateral vs central), and completion of aCTH course to be significantly associated with OS; p<0.05. On multivariable analysis, however, only aCTH completion demonstrated a trend for better OS; HR = 0.15 (95% CI: 0.02-1.27, p = 0.08). KM survival analysis revealed superior 5-year OS and PFS in patients who completed aCTH compared to those who received RT alone or did not complete aCTH: 88.9% vs 68.6% vs 40%, p = 0.03 and 83.3% vs 59.3% vs 42%, p = 0.04, respectively. Our series demonstrates that completion of aCTH provides a significant OS and PFS advantage for adult medulloblastoma patients. Prospective studies are needed to develop optimal treatment approaches for these patients who have the potential for long term survival.Abstract 3734; TableVariableN (%)Age (median, interquartile range (IQR))29 (22-33)SexFemale: 13 (41) Male: 19 (59)Histologic subtypeClassic: 6 (19) Desmoplastic/nodular: 6 (19) Large cell/Anaplastic: 4 (12) Not available (NA):16 (50)Risk groupAverage: 19 (59) High: 6 (19) NA: 7 (22)LateralityLateral: 16 (50) Central: 16 (50)Extent of resectionGross total resection (GTR): 24 (75) Non-GTR: 8 (25)Craniospinal irradiation dose (Gray (Gy))23.4 Gy: 10 (31) 36 Gy: 17 (53) NA: 5 (16)Adjuvant chemotherapy (aCTH)None: 10 (31) A9961 CCNU: 12 (38) A9961 cyclophosphamide: 1 (3) ACNS0331: 5 (16) Other/NA: 4 (12)Treatment outcomes (months(mo), median, IQR)Local control duration: 39 (13-141) Freedom from distant metastasis duration: 47 (19-141) Overall survival duration: 54 (26-141) Open table in a new tab