BlueCross BlueShield of Tennessee Medical Policy Manual

Hematopoietic Stem Cell Transplantation for Central Nervous System Embryonal and Ependymoma Tumors


Hematopoietic stem cell transplantation (HSCT) refers to a procedure in which hematopoietic stem cells are infused to restore bone marrow function in individuals with cancer who receive bone-marrow-toxic doses of cytotoxic drugs. Hematopoietic stem cells may be obtained from the transplant recipient (i.e., autologous stem cell transplantation) or from a donor (i.e., allogeneic stem cell transplantation). They may be harvested from bone marrow, peripheral blood, or umbilical cord blood shortly after delivery of neonates. High-dose chemotherapy with hematopoietic stem cell transplantation has been investigated as a possible therapy in pediatric brain tumors, particularly those with disease considered high risk.

CNS Embryonal Tumors

Classification of brain tumors is based on both histopathologic characteristics of the tumor and location in the brain. CNS embryonal tumors are more common in children and are the most common brain tumor in childhood. Embryonal tumors of the central nervous system (CNS) include medulloblastoma, medulloepithelioma, supratentorial PNETs (pineoblastoma, cerebral neuroblastoma, ganglioneuroblastoma), ependymoblastoma, and atypical teratoid/rhabdoid tumor). Medulloblastomas account for 20% of all childhood CNS tumors. The other types of embryonal tumors are rare by comparison. Surgical resection is the mainstay of therapy with the goal being gross total resection with adjuvant radiation therapy, as medulloblastomas are very radiosensitive. In general, use of autologous hematopoietic cell transplantation in individuals with medulloblastoma who have not received radiation treatment has shown no survival benefit for those individuals considered to be at average risk (i.e., individual age greater than 3 years, without metastatic disease, and with total or near total surgical resection [less than 1.5cm2 residual tumor]).

Ependymoma Tumor

An ependymoma is a neuroepithelial tumor that arises from the ependymal lining cell of the ventricles and is, therefore, usually contiguous with the ventricular system. In children, the tumor typically arises intracranially, while in adults, a spinal cord location is more common. Ependymomas have access to the cerebrospinal fluid and may spread throughout the entire neuroaxis and are distinct from ependymoblastomas due to their more mature histologic differentiation. Initial treatment of ependymoma consists of maximal surgical resection followed by radiotherapy. Disease relapse is common, typically occurring at the site of origin. Treatment of recurrence is problematic as further surgical resection or radiation therapy is usually not possible. Given the poor response to conventional-dose chemotherapy, high-dose chemotherapy with autologous hematopoietic stem cell transplantation has been investigated as a possible salvage therapy.





The evidence to support hematopoietic stem cell transplantation for the treatment of ependymoma includes relatively small case series. The results of these studies do not report higher survival rates for individuals treated with HSCT compared with standard therapies. The evidence is insufficient to determine the effects of the technology on health outcomes.


BlueCross BlueShield Association. Evidence Positioning System. (2:2019). Hematopoietic cell transplantation for central nervous system embryonal tumors and ependymoma (8.01.28). Retrieved August 15, 2019 from (37 articles and/or guidelines reviewed)

Centers for Medicare & Medicaid Services. NCD for stem cell transplantation (110.23). Retrieved October 24, 2016 from

National Cancer Institute. (2017, September).Childhood central nervous system embryonal tumors treatment (PDQ®). Retrieved October 10, 2017 from

National Cancer Institute. (2017, September). Childhood ependymoma treatment (PDQ®). Retrieved October 10, 2017 from

National Comprehensive Cancer Network. (2018, March). NCCN Guidelines for the Treatment of Cancer (NCCN Guidelines®).Central nervous system cancers (V.1.2018). Retrieved August 31, 2018 from the National Comprehensive Cancer Network.

Raleigh, D., Tomlin, B., Buono, B., Roddy, E., Sear, K., Byer, L., et al. (2017). Survival after chemotherapy and stem cell transplant followed by delayed craniospinal irradiation is comparable to upfront craniospinal irradiation in pediatric embryonal brain tumor patients. Journal of Neuro-Oncology, 131 (2), 359-368. Abstract retrieved October 11, 2017 from PubMed database.

Sung, K., Lim, D., Lee, S., Yoo, K., Koo, H., Kim, J., et al. (2012). Tandem high-dose chemotherapy and autologous stem cell transplantation for anaplastic ependymoma in children younger than 3 years of age. Journal of Neurooncology 107 (2), 335-342. Abstract retrieved October 24, 2016 from PubMed database.

Winifred S. Hayes, Inc. Medical Technology Directory. (2013, December; last update search December 2017). Autologous stem cell transplantation (ASCT) for metastatic primitive neuroectodermal tumor (PNET). Retrieved August 31, 2018 from (36 articles and/or guidelines reviewed)




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