RTHP-08. RE-EVALUATING THE SEQUENCING OF RADIOTHERAPY AND CHEMOTHERAPY IN PEDIATRIC MEDULLOBLASTOMA. (5th November 2018)

• Record Type: Journal Article
• Authors: Hess, Clayton; Yeap, Beow; Sahasakmontri, Jay; Lawell, Miranda; Weyman, Elizabeth; Gallotto, Sara; Bajaj, Benjamin; Sieger, Kira; MacDonald, Shannon; Marcus, Karen; Kieran, Mark; Huang, Mary; Tarbell, Nancy; Ebb, David; Yock, Torunn
• Is Part Of: Neuro-oncology. Volume 20(2018)Supplement 6
• Page Start: vi226
• Page End: vi227
• Publication Date: 2018-11-05
• Subjects: Brain Neoplasms -- Periodicals; Brain -- Tumors -- Periodicals; Brain -- Cancer -- Periodicals; Nervous system -- Cancer -- Periodicals; 616.99481
• DOI: 10.1093/neuonc/noy148.940
• Languages: English
• ISSNs: 1522-8517

Abstract

Abstract: BACKGROUND: Standard treatment for medulloblastoma in children over age 3 includes resection and radiotherapy, followed by chemotherapy. Some studies have found disease control decrements if chemotherapy was delivered before radiotherapy. However, these studies recommended radiation interruptions for hematologic toxicity, which were more severe in children receiving chemotherapy prior to craniospinal radiotherapy. We report outcomes of pediatric medulloblastoma patients treated post-operatively with radiotherapy-first (RT1) or chemotherapy-first CT1). POPULATION/ METHODS: 206 patients age 2–23 years with medulloblastoma were treated with proton radiotherapy from May 2000 to December 2016. We analyzed the effect of sequencing radiotherapy first (n=164) or chemotherapy first (n=42) after surgery on event-free (EFS) and overall survival (OS) controlling for known risk factors. RESULTS: Median follow-up was 5.8 years. Children who received CT1 sequencing were younger (p<0.0001), more likely to receive high-dose chemotherapy (p<0.001), have high/intermediate risk disease (p<0.0001), M1-M3 stage (p<0.001), and large-cell/anaplastic histology (p=0.04). M1-M3 stage (p=0.01), high/intermediate risk disease (p=0.03), and anaplastic/large-cell histology (p=0.04) were all predictive of worse EFS. Despite higher proportions of risk factors in the CT1 cohort, 5-year EFS and OS in the RT1 versus CT1 groups were no different at 89% versus 84% (p=0.39) and 90% versus 84% (p=0.33), and remained equivalent when controlling for M1-M3 stage and unfavorable histology (p=0.86). Radiation treatment duration was equivalent at a median of 43 days (RT1) and 42 days (CT1) (p=0.4). Children with anaplastic/large-cell histology had lower EFS only in the RT1 cohort (64% vs. 87%, p=0.01) and equivalent EFS in the CT1 cohort (73% vs. 78%, p=0.88), suggesting a possible benefit to high-dose chemotherapy before RT in children with unfavorable histology. CONCLUSIONS: Disease control and overall survival were equivalent in the radiotherapy-first and chemotherapy-first cohorts when radiation treatment times were minimized.