A longitudinal study of processing speed among children treated for medulloblastoma (MB), supratentorial primitive neuroectodermal tumor (SPNET), or atypical teratoid rhabdoid tumor (ATRT)

Abstract

10028 Background: Indicating a strong relationship to intelligence, processing speed parallels with the rate of knowledge acquisition. To further our understanding of the etiology of deficits in intellectual ability that continues to plague this group of children, the current study prospectively examined longitudinal changes in an underlying cognitive ability, processing speed. Methods: The study included 174 patients (median age at diagnosis = 9.0) enrolled on a multi-site protocol (SJMB03) for MB, SPNET or ATRT. Patients were treated with post-surgical risk-adapted craniospinal irradiation (CSI) followed by 4 cycles of high-dose chemotherapy (cyclophosphamide, cisplatin, vincristine) with stem cell support. High risk (HR, n = 55) patients received 36 - 39.6 Gy CSI and 3D conformal boost to the primary site to 55.8 –59.4 Gy. Average-risk (AR, n=119) patients received 23.4 Gy CSI, 3D conformal boost to the primary site to 55.8 Gy. Those who had posterior fossa syndrome were excluded (n = 26) resulting in 148 patients who completed 459 neuropsychological evaluations using the Woodcock Johnson Tests of Cognitive Abilities-III over a period of 0.03 –4.94 years postdiagnosis. Results: Multivariate modeling revealed a statistically significant decline in processing speed for those < 7 years of age at time of diagnosis (-3.83 points per year, p = 0.003). Those who were > 7 years at diagnosis did not experience a significant change (.86, NS). HR patients experienced greater declines (-.82) than those who were AR (-0.29), but neither slope was statistically significant. Interaction models revealed declines for those in the <7/AR group (-4.17, p = 0.003), and <7/HR group (-3.38, NS). Those >7/AR and >7/HR did not experience significant change (1.06 and 0.32, respectively). Conclusions: Young age at diagnosis is a prominent risk factor for processing speed impairment among survivors of pediatric embryonal tumors. Processing speed may also be among the first deficits to appear following treatment. This study represents the largest comparison of processing speed ability among patients treated for pediatric embryonal tumors with conventional or reduced dose CSI and adjuvant chemotherapy. No significant financial relationships to disclose.