Recurrence of all forms of central nervous system embryonal tumors is not uncommon, usually occurring within 18 months of treatment; however, recurrent tumors may develop many years after initial treatment.[1,2] Disease may recur at the primary site or may be disseminated at the time of relapse. Sites of noncontiguous relapse may include the spinal leptomeninges, intracranial sites, and cerebrospinal fluid, in isolation or in any combination, and is variably associated with primary tumor relapse.[1-3] One series has found that, independent of the dose of radiation therapy employed or the type of chemotherapy utilized, approximately one-third of patients will relapse at the primary tumor site alone, one-third at the primary tumor site plus distant sites, and one-third at distant sites without relapse at the primary site.[1-3] At the time of relapse, a complete evaluation for extent of recurrence is indicated for all embryonal tumors. Biopsy or surgical resection may be necessary for confirmation of relapse because other entities such as secondary tumors and treatment-related brain necrosis may be clinically indistinguishable from tumor recurrence. The need for surgical intervention must be individualized on the basis of the initial tumor type, the length of time between initial treatment and the reappearance of the lesion, and clinical symptomatology. Extraneural disease relapse may occur but is rare and is seen primarily in patients treated with radiation therapy alone.

Patients with recurrent embryonal tumors can be responsive to conventional chemotherapy that includes a variety of chemotherapeutic agents used singularly or in combination, including cyclophosphamide, cisplatinum, carboplatinum, lomustine, and etoposide.[4-12] Approximately 30% to 50% of these patients will have objective response to conventional chemotherapy, but long-term disease control is rare. Higher-dose chemotherapeutic regimens, supported with autologous bone marrow rescue or peripheral stem-cell support, have been used with variable results.[13] With such regimens, objective response is frequent, occurring in 50% to 75% of patients; however, long-term disease control is obtained in fewer than 30% of patients and is primarily seen in patients in first relapse and in those with only localized disease at the time of relapse. Long-term disease control for patients with disseminated disease is infrequent. Information about ongoing clinical trials is available from the NCI Web site.

References

1. Taylor RE, Bailey CC, Robinson K, et al.: Results of a randomized study of preradiation chemotherapy versus radiotherapy alone for nonmetastatic medulloblastoma: The International Society of Paediatric Oncology/United Kingdom Children's Cancer Study Group PNET-3 Study. J Clin Oncol 21 (8): 1581-91, 2003.  [PUBMED Abstract]
   
   
2. Packer RJ, Goldwein J, Nicholson HS, et al.: Treatment of children with medulloblastomas with reduced-dose craniospinal radiation therapy and adjuvant chemotherapy: A Children's Cancer Group Study. J Clin Oncol 17 (7): 2127-36, 1999.  [PUBMED Abstract]
   
   
3. Oyharcabal-Bourden V, Kalifa C, Gentet JC, et al.: Standard-risk medulloblastoma treated by adjuvant chemotherapy followed by reduced-dose craniospinal radiation therapy: a French Society of Pediatric Oncology Study. J Clin Oncol 23 (21): 4726-34, 2005.  [PUBMED Abstract]
   
   
4. Friedman HS, Oakes WJ: The chemotherapy of posterior fossa tumors in childhood. J Neurooncol 5 (3): 217-29, 1987.  [PUBMED Abstract]
   
   
5. Needle MN, Molloy PT, Geyer JR, et al.: Phase II study of daily oral etoposide in children with recurrent brain tumors and other solid tumors. Med Pediatr Oncol 29 (1): 28-32, 1997.  [PUBMED Abstract]
   
   
6. Gaynon PS, Ettinger LJ, Baum ES, et al.: Carboplatin in childhood brain tumors. A Children's Cancer Study Group Phase II trial. Cancer 66 (12): 2465-9, 1990.  [PUBMED Abstract]
   
   
7. Gentet JC, Doz F, Bouffet E, et al.: Carboplatin and VP 16 in medulloblastoma: a phase II Study of the French Society of Pediatric Oncology (SFOP). Med Pediatr Oncol 23 (5): 422-7, 1994.  [PUBMED Abstract]
   
   
8. Allen JC, Walker R, Luks E, et al.: Carboplatin and recurrent childhood brain tumors. J Clin Oncol 5 (3): 459-63, 1987.  [PUBMED Abstract]
   
   
9. Ashley DM, Longee D, Tien R, et al.: Treatment of patients with pineoblastoma with high dose cyclophosphamide. Med Pediatr Oncol 26 (6): 387-92, 1996.  [PUBMED Abstract]
   
   
10. Lefkowitz IB, Packer RJ, Siegel KR, et al.: Results of treatment of children with recurrent medulloblastoma/primitive neuroectodermal tumors with lomustine, cisplatin, and vincristine. Cancer 65 (3): 412-7, 1990.  [PUBMED Abstract]
    
    
11. Friedman HS, Mahaley MS Jr, Schold SC Jr, et al.: Efficacy of vincristine and cyclophosphamide in the therapy of recurrent medulloblastoma. Neurosurgery 18 (3): 335-40, 1986.  [PUBMED Abstract]
    
    
12. Castello MA, Clerico A, Deb G, et al.: High-dose carboplatin in combination with etoposide (JET regimen) for childhood brain tumors. Am J Pediatr Hematol Oncol 12 (3): 297-300, 1990.  [PUBMED Abstract]
    
    
13. Dunkel IJ, Boyett JM, Yates A, et al.: High-dose carboplatin, thiotepa, and etoposide with autologous stem-cell rescue for patients with recurrent medulloblastoma. Children's Cancer Group. J Clin Oncol 16 (1): 222-8, 1998.  [PUBMED Abstract]
    
    

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