Clinical investigation
Brain
Distinctive clinical course and pattern of relapse in adolescents with medulloblastoma

https://doi.org/10.1016/j.ijrobp.2005.07.962Get rights and content

Purpose: To report the clinical course of adolescents with medulloblastoma, with specific emphasis on prognosis and pattern of relapse.

Methods and Materials: We retrospectively studied the clinical course and outcomes of children aged 10–20 years with medulloblastoma, treated at centers throughout Canada between 1986 and 2003. To better assess time to relapse, a cohort of patients aged 3–20 years at diagnosis was generated.

Results: A total of 72 adolescents were analyzed. Five-year overall survival and event-free survival rates were 78.3% ± 5.4% and 68.0% ± 6.2%, respectively. Late relapses occurred at a median of 3.0 years (range, 0.3–6.8 years). In univariate analysis, conventional risk stratification and the addition of chemotherapy to craniospinal radiation did not have prognostic significance. Female patients had improved overall survival (p = 0.007). Time to relapse increased with age in a linear fashion. After relapse, patients faired poorly regardless of treatment modality. Patients who did not receive chemotherapy initially had improved progression-free survival at relapse (p = 0.05).

Conclusions: Our study suggests that adolescents with medulloblastoma might have a unique prognosis and pattern of relapse, dissimilar to those in younger children. They might benefit from different risk stratifications and prolonged follow-up. These issues should be addressed in future prospective trials.

Introduction

Medulloblastoma is a highly malignant embryonal central nervous system (CNS) tumor primarily affecting children in the first decade of life. This is the most common malignant brain tumor of childhood, accounting for 20–25% of pediatric CNS neoplasms. Large cooperative and epidemiology studies have contributed to better-defined risk groups and improved treatment modalities and outcomes (1, 2, 3, 4, 5, 6). The pattern of relapse in childhood medulloblastoma has been extensively described (6, 7, 8). Being an embryonal tumor, medulloblastoma is rare in older people and represents <1% of CNS tumors in adults (9). Nevertheless, over the last decade, several retrospective institutional or multicenter studies have described the characteristics, response to treatment, prognosis, and pattern of relapse in adult medulloblastoma (10, 11, 12, 13, 14). Some aspects of adult medulloblastoma differ markedly from what is observed in younger children. For example, conventional pediatric risk groups might not apply to adult patients. The prognosis for these adult patients seems to be favorable, but late relapses are more common. Recently, cancer in adolescents has been identified as an important entity because adolescents constitute a significant and unique group with regard to treatment and prognosis. In most pediatric medulloblastoma series, mean age at diagnosis is 6–8 years (1, 2, 4, 5, 6). Furthermore, adolescents were never evaluated separately, indicating that most available data might not apply to this group. Moreover, up to 27% of medulloblastoma patients are >10 years of age at diagnosis (15), making them a neglected but considerable group of patients. The discrepancy between the findings in adult and pediatric studies mandates a closer look at patients in transition from childhood into adulthood.

Our aim was to report the clinical course of patients with medulloblastoma aged 10–20 years at diagnosis, with specific emphasis on prognosis and pattern of relapse.

Section snippets

Patients

We performed a multicenter retrospective study that included 10 centers participating in the Canadian Pediatric Brain Tumor Consortium (CPBTC). The CPBTC is a group of tertiary care Canadian centers involved in the development and conduct of studies related to pediatric brain tumors. We reviewed the charts of patients aged ≥10 years and ≤20 years at diagnosis, who were defined as teenagers, treated at these centers between 1986 and 2003 with a diagnosis of medulloblastoma. This study was

Study population and treatment approach

Data were available for 77 adolescents from 10 pediatric cancer centers of the CPBTC. Five patients were excluded owing to insufficient data, thus 72 adolescents were included in this study. Demographic, clinical, and treatment characteristics are listed in Table 1. Craniospinal irradiation with a boost of 51–55 Gy to the tumor bed was given to all patients, including the younger controls. All but 1 patient from the high-risk group received ≥35 Gy to the craniospinal axis. Of the 45 patients in

Discussion

The aim of this multicenter, retrospective study was to describe the survival characteristics and the pattern of relapse in adolescents with medulloblastoma. Our findings support the growing hypothesis that adolescents with cancer are distinct from younger children and constitute a separate group. In our experience, OS and EFS at 5 and 8 years revealed a pattern that seems different from previous reports in younger patients (Table 2). Although the 5-year pattern compared favorably with most

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