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Timing of radiation in children with medulloblastoma/PNET
Marcos A Santos1, Célia M P Viégas, Renata A Servidoni
1Department of Radiation Oncology, Instituto Nacional de Câncer (INCA), Rio de Janeiro, Brazil. mrcsantos@uol.com.br
Insights
Radiation therapy timing is crucial for pediatric medulloblastoma survival. A biological effective dose (BED) over 44 Gy10 significantly improves outcomes for children with central nervous system (CNS) PNET.
Area of Science:
- Pediatric Oncology
- Radiation Oncology
- Neuro-oncology
Background:
- Medulloblastoma is a common pediatric central nervous system (CNS) tumor.
- Optimizing treatment timing, including radiation therapy, is critical for improving survival rates in pediatric PNET/medulloblastoma.
- The Brazilian National Cancer Institute (INCA) has treated numerous pediatric cases, providing valuable data for analysis.
Purpose of the Study:
- To evaluate the impact of radiation therapy timing on treatment outcomes in pediatric medulloblastoma patients.
- To identify prognostic factors influencing survival in children diagnosed with PNET/medulloblastoma.
- To determine optimal radiation dose parameters for improved disease-free survival (DFS) and overall survival (OS).
Main Methods:
- Retrospective review of 101 pediatric medulloblastoma cases treated between 1983 and 2001.
- Analysis of patient demographics, treatment details, and follow-up data (median 48 months).
- Multivariate analysis to identify predictors of overall survival (OS) and disease-free survival (DFS).
Main Results:
- Overall survival (OS) was 53%, and disease-free survival (DFS) was 40%.
- Younger age (under 3 years), positive cerebrospinal fluid (CSF) cytology, and subtotal resection were associated with worse OS.
- Higher biological effective dose (BED) > 44 Gy10 correlated with better prognosis.
Conclusions:
- Total tumor resection and negative CSF cytology are key predictors of favorable OS.
- Radiation therapy is more effective when a BED greater than 44 Gy10 is achieved.
- Optimizing radiation dose and surgical approach improves outcomes for pediatric medulloblastoma.
Background:
To evaluate the importance of timing of radiation therapy in children with PNET/medulloblastoma, treated at the Brazilian National Cancer Institute (INCA).
Procedure:
The records of 101 children with confirmed diagnosis of medulloblastoma were retrospectively reviewed. Patients had a median follow-up of 48 months (0.5-241 months). The age varied from 0.8 to 17.5 years (median: 7.6 years) and 21.7% were 3 years old or younger.
Results:
According to the data collected from patients that received treatment for medulloblastoma from 1983 to 2001, the overall survival (OS) rate was 53% and the Disease Free Survival (DFS) rate was 40%. Multivariate analysis showed that under age 3 years, presence of neoplasic cells in the cerebrospinal fluid (CSF) at presentation or subtotal tumor resection resulted in a worse OS. The patients that received a biological effective dose (BED) greater than 44 Gy10 had better prognosis. Two-thirds of the patients had complete response after the initial treatment. Among them, 50% (34 patients) recurred, and of those 34 patients, 42% of them (14 patients) had recurrence in the posterior fossa.
Conclusion:
Surgery with total resection of the tumor and absence of neoplasic cells in the CSF are effective predictors of better OS. Radiotherapy was more effective when a BED was greater than 44 Gy10.
