BACKGROUND: Radiotherapy boost to the entire posterior fossa (PF) is standard of care for high-risk (H-R) medulloblastoma patients; the utility of tumor bed (TB)-only boost is unclear. The purpose of this study was to examine the impact of PF versus TB boost volume on tumor control and survival in the H-R medulloblastoma population. METHODS: Single-institution records for patients with H-R medulloblastoma were reviewed. The median craniospinal irradiation dose was 36 Gy (range, 23.4-45 Gy), and boost doses to either PF or TB were 54 to 55.8 Gy. PF (local) failures were scored as in-field, marginal (between 80% and 95% isodose lines), or distant. Kaplan-Meier methods and Cox proportional hazards were used to assess the impact of radiation boost technique on local control (LC) and survival endpoints. RESULTS: Thirty-two patients with H-R medulloblastoma were treated between 1990 and 2015, with a median follow-up length of 5.12 years. Twenty-two patients received PF boost, and 10 received TB boost. Patient and disease characteristic were comparable between groups. A total of 11 PF failures occurred, including 3 isolated LFs (2 in the PF and 1 in the TB group). Most PF failures were in-field: three of four in the TB group and six of seven in the PF group; the remainder were marginal failures. TB boost was not associated with inferior LC (hazard ratio [HR] 0.86, log-rank P = 0.81) or overall survival (HR 1.40, P = 0.56) compared with PF boost. CONCLUSION: Reduced-volume radiotherapy boost to the TB does not appear to compromise LC or survival in patients with H-R medulloblastoma; it may reduce the risk of ototoxicity.
BACKGROUND: Radiotherapy boost to the entire posterior fossa (PF) is standard of care for high-risk (H-R) medulloblastomapatients; the utility of tumor bed (TB)-only boost is unclear. The purpose of this study was to examine the impact of PF versus TB boost volume on tumor control and survival in the H-R medulloblastoma population. METHODS: Single-institution records for patients with H-R medulloblastoma were reviewed. The median craniospinal irradiation dose was 36 Gy (range, 23.4-45 Gy), and boost doses to either PF or TB were 54 to 55.8 Gy. PF (local) failures were scored as in-field, marginal (between 80% and 95% isodose lines), or distant. Kaplan-Meier methods and Cox proportional hazards were used to assess the impact of radiation boost technique on local control (LC) and survival endpoints. RESULTS: Thirty-two patients with H-R medulloblastoma were treated between 1990 and 2015, with a median follow-up length of 5.12 years. Twenty-two patients received PF boost, and 10 received TB boost. Patient and disease characteristic were comparable between groups. A total of 11 PF failures occurred, including 3 isolated LFs (2 in the PF and 1 in the TB group). Most PF failures were in-field: three of four in the TB group and six of seven in the PF group; the remainder were marginal failures. TB boost was not associated with inferior LC (hazard ratio [HR] 0.86, log-rank P = 0.81) or overall survival (HR 1.40, P = 0.56) compared with PF boost. CONCLUSION: Reduced-volume radiotherapy boost to the TB does not appear to compromise LC or survival in patients with H-R medulloblastoma; it may reduce the risk of ototoxicity.
Authors: John T Lucas; Christopher L Tinkle; Jie Huang; Arzu Onar-Thomas; Sudharsan Srinivasan; Parker Tumlin; Jared B Becksfort; Paul Klimo; Frederick A Boop; Giles W Robinson; Brent A Orr; Julie H Harreld; Matthew J Krasin; Paul A Northcott; David W Ellison; Amar Gajjar; Thomas E Merchant Journal: Neuro Oncol Date: 2022-07-01 Impact factor: 13.029