Atypical Teratoid/Rhabdoid Tumor of the Central Nervous System: Report on Workshop

Abstract

Childhood atypical teratoid/rhabdoid tumor (AT/RT) of the central nervous system (CNS) is a recently described entity. Diagnosis is based on distinctive light microscopy and immunohistochemical findings, coupled with molecular genetic analysis. Most AT/RTs demonstrate monosomy 22 or deletions of chromosome band 22q11 with alterations of the hSNF5/INI1 gene. The tumor's incidence is still undefined, but it may comprise as high as 1 in 4 primitive CNS tumors in infants. Treatment is far from optimal, but there are occasional long-term survivors, especially among older children. Therapeutic approached have included surgery, chemotherapy, and radiotherapy. Prospective clinical trials are needed for children with AT/RTs.

Survival outcomes in atypical teratoid rhabdoid tumor for patients undergoing radiotherapy in a Surveillance, Epidemiology, and End Results analysis

“…This is comparable to the survival reported in studies that were published before 2008. 1,3,4,10,12 The median age of patients in our study was 1 year, which represents a younger population compared with most other studies. 1,10,11,13,14 Younger age at diagnosis has been associated with a worse prognosis for patients with ATRT.…”

“…[1][2][3][4][5] ATRT is extremely rare in adults, and only 31 patients have been reported in the literature. 6 Originally described in the 1980s, ATRT has been widely recognized as a rare but important clinical entity only over the past decade.…”

“…The prognosis for patients with ATRT remains dismal, and the historic median overall survival (OS) ranges from 6 months to 18 months. 1,3,4,9,10 Therapeutic approaches for ATRT historically have relied on data from treatments of other childhood CNS tumors, particularly primitive neuroendocrine tumors and medulloblastoma, which have a considerably better prognoses. 5 However, preliminary results from the first prospective clinical trial in children with ATRT indicate that intensive multimodality treatment, including resection, CNS radiotherapy (RT), and chemotherapy based on the Intergroup Rhabdomyosarcoma Study Group (IRS) III protocol, may lead to longer survival, with an estimated 2-year OS survival rate of 70% AE 10%.…”

“…6 Originally described in the 1980s, ATRT has been widely recognized as a rare but important clinical entity only over the past decade. 2,4 The diagnosis of ATRT has been greatly facilitated by the rise in accessibility of immunohistochemical testing in the late 1990s, which takes advantage of the frequent loss of switch/sucrose nonfermentable (SWI/SNF)-related, matrix-associated, actin-dependent regulator of chromatin, subfamily b, member 1 (SMARCB1) (also known as SNF5 homolog [hSNF5] and INI1) tumor suppressor gene products in these tumors. 2,5,7 Although ATRT comprises <5% of CNS tumors in children aged <18 years, it reportedly represents up to 20% of CNS tumors in children aged <3 years.…”

“…2,5,7 Although ATRT comprises <5% of CNS tumors in children aged <18 years, it reportedly represents up to 20% of CNS tumors in children aged <3 years. 1,4,8 However, it is believed that the true incidence may be higher because of misdiagnosis given similarities in imaging and histologic appearance to other high-grade embryonal CNS malignancies. 2,3,8,9 Current knowledge describing clinical characteristics, prognosis, and therapy for ATRT is derived mostly from small, retrospective, observational studies.…”