Infant brain tumors: incidence, survival, and the role of radiation based on Surveillance, Epidemiology, and End Results (SEER) Data

Infant brain tumors: a neuropathologic population-based institutional reappraisal

The factors that impact the long-term functional outcome for infants with brain tumor are unclear. The clinicopathologic features of all infant brain tumors occurring at our institution (1982-2005) were reexamined to explore the factors influencing prognosis. The details of the neuropathologic review are reported herein. Thirty-five cases were identified and included 7 astrocytomas (6 low grade and 1 glioblastoma), 6 atypical teratoid rhabdoid tumors, 5 choroid plexus papillomas, 4 ependymomas (3 anaplastic), 4 teratomas (3 immature), 2 supratentorial primitive neuroectodermal tumors, 2 gangliogliomas, 2 desmoplastic tumors of infancy, and 1 each of "medulloblastoma with extensive nodularity," adamantinomatous craniopharyngioma, and 1 "malignancy not otherwise specified." The original diagnosis was changed in 8 cases (23%), and atypical teratoid rhabdoid tumors was the most common revision (n = 5). Case 9 was unusual in that both the patient and her 2-year-old sister displayed INI-1 immunonegative posterior fossa tumors and extended survival. Tumor grade was altered in 6 cases (17%), the most significant instance being the downgrading from the World Health Organization grade IV to I (case 18: supratentorial primitive neuroectodermal tumors to desmoplastic tumors of infancy). As opposed to other reports in the literature, our cohort contained a substantially higher frequency of atypical teratoid rhabdoid tumors and a lower frequency of medulloblastoma. Changes in the histologic diagnosis/grade in a significant subset of cases most likely reflect the continual evolution of brain tumor classification schemes. INI-1 immunohistochemistry was instrumental in the pathologic assessment of select cases and raised the possibility that atypical teratoid rhabdoid tumors may be the most common infant brain malignancy.

Sequencing of local therapy affects the pattern of treatment failure and survival in children with atypical teratoid rhabdoid tumors of the central nervous system

PURPOSE

To assess the pattern of treatment failure associated with current therapeutic paradigms for childhood atypical teratoid rhabdoid tumors (AT/RT).

METHODS AND MATERIALS

Pediatric patients with AT/RT of the central nervous system treated at our institution between 1987 and 2007 were retrospectively evaluated. Overall survival (OS), progression-free survival, and cumulative incidence of local failure were correlated with age, sex, tumor location, extent of disease, and extent of surgical resection. Radiotherapy (RT) sequencing, chemotherapy, dose, timing, and volume administered after resection were also evaluated.

RESULTS

Thirty-one patients at a median age of 2.3 years at diagnosis (range, 0.45-16.87 years) were enrolled into protocols that included risk- and age-stratified RT. Craniospinal irradiation with focal tumor bed boost (median dose, 54 Gy) was administered to 18 patients. Gross total resection was achieved in 16. Ten patients presented with metastases at diagnosis. RT was delayed more than 3 months in 20 patients and between 1 and 3 months in 4; 7 patients received immediate postoperative irradiation preceding high-dose alkylator-based chemotherapy. At a median follow-up of 48 months, the cumulative incidence of local treatment failure was 37.5% ± 9%; progression-free survival was 33.2% ± 10%; and OS was 53.5% ± 10%. Children receiving delayed RT (≥1 month postoperatively) were more likely to experience local failure (hazard ratio [HR] 1.23, p = 0.007); the development of distant metastases before RT increased the risk of progression (HR 3.49, p = 0.006); and any evidence of disease progressionbefore RT decreased OS (HR 20.78, p = 0.004). Disease progression occurred in 52% (11/21) of children with initially localized tumors who underwent gross total resection, and the progression rate increased proportionally with increasing delay from surgery to RT.

CONCLUSIONS

Delayed RT is associated with a higher rate of local and metastatic disease progression in children with AT/RT. Current treatment regimens for pediatric patients with AT/RT are distinctly age stratified; novel protocols investigating RT volumes and sequencing are needed.