Pediatric Cancer

SS 38 - Pediatric 2

223 - Outcomes After Radiation Therapy for Very Young Children with High-Risk Medulloblastoma or Supratentorial Primitive Neuroectodermal Tumor Treated on COG ACNS0334

Wednesday, September 18
1:45 PM - 1:55 PM
Location: Room W179

Outcomes After Radiation Therapy for Very Young Children with High-Risk Medulloblastoma or Supratentorial Primitive Neuroectodermal Tumor Treated on COG ACNS0334
P. D. Aridgides1, G. Kang2, C. Mazewski3, and T. E. Merchant2; 1SUNY Upstate Medical University, Syracuse, NY, 2St. Jude Children's Research Hospital, Memphis, TN, 3Emory University School of Medicine, Atlanta, GA

Purpose/Objective(s): To assess the optional use of radiation therapy (RT) for the Children’s Oncology Group ACNS0334 protocol and the impact of RT sequencing on overall survival (OS).

Materials/Methods: The original study included 77 evaluable children age < 36 months with high-risk medulloblastoma (HR-MB) or supratentorial primitive neuroectodermal tumor (SPNET). Patients with HR-MB had neuraxis metastatic disease (M+) and/or residual primary tumor measuring > 1.5cm2. Patients with SPNET were enrolled regardless of M+ or residual primary tumor. The treatment regimen was post-operative induction chemotherapy (vincristine, etoposide, cyclophosphamide, cisplatin), with or without methotrexate (randomized), followed by 3 cycles of consolidation chemotherapy (thiotepa, carboplatin) with stem-cell rescue. RT records were obtained and analyzed through a database records request (ACNS15D1). RT was given at completion of chemotherapy (frontline) in 11 and at time of tumor progression in 13. RT was optional and guidelines were based upon response and age. The use of RT was classified as craniospinal irradiation (CSI), focal, palliative, or unknown. Upfront RT recommendations included primary site dose of 50-54Gy (cumulative total) and 18Gy CSI (M+). Statistical analyses included Kaplan-Meier survival estimates and Fischer's exact test.

Results: The 5-year OS was 51% for HR-MB and 25% for SPNET for patients treated with RT. HR-MB: Frontline RT was delivered to 8 patients after partial response to chemotherapy including 7 with persistent M+. CSI doses were 18Gy (n=2), 23.4Gy (n=3), and 36Gy (n=1). Two patients received focal RT. There were no primary site failures (median dose 54Gy). Four survivors had no evidence of disease (NED); 4 progressed in the neuraxis and died. RT at progression was delivered to 3 M+ patients; 2 are NED after CSI (≥36Gy). The use of CSI was not associated with improved OS. For HR-MB OS was similar for patients treated upfront or at relapse, however all survivors from relapse RT received full dose CSI. Frontline RT survivors were treated with focal RT (n=2) and CSI (n=2). SPNET: Frontline RT was administered to 3 patients. Two patients without metastatic disease (M0) were alive after focal treatment (50.4-54Gy) and the remaining patient (M+) died of neuraxis progression after 18Gy CSI. Ten patients were treated at the time of progression including 7 who experienced a complete response to chemotherapy. There was one survivor (M0) who received 18Gy CSI and 54Gy to the primary site. Frontline RT was associated with improved OS for SPNET (p=0.03). CSI was not associated with improved OS.

Conclusion: RT administered to very young children with HR-MB and SPNET results in long-term survival. For patients with SPNET, frontline RT appears superior to treatment at relapse where only 1 in 10 patients treated survived. HR-MB survivors after frontline RT included those treated with focal RT or reduced dose CSI. The selection of the appropriate treatment volume requires further investigation.

Author Disclosure: P.D. Aridgides: None. G. Kang: None. C. Mazewski: None. T.E. Merchant: None.

Paul Aridgides, MD

SUNY Upstate Medical University

Disclosure:
Employment
SUNY Upstate Medical University

Presentation(s):

Send Email for Paul Aridgides


Assets

223 - Outcomes After Radiation Therapy for Very Young Children with High-Risk Medulloblastoma or Supratentorial Primitive Neuroectodermal Tumor Treated on COG ACNS0334



Attendees who have favorited this

Please enter your access key

The asset you are trying to access is locked. Please enter your access key to unlock.

Send Email for Outcomes After Radiation Therapy for Very Young Children with High-Risk Medulloblastoma or Supratentorial Primitive Neuroectodermal Tumor Treated on COG ACNS0334