Introduction: The current prognosis of medulloblastoma in children is better than before because of technological advancements and improvements in treatment strategies and genetic investigation. At the same time, there is a lack of studies focused on medulloblastoma in Thailand. The aim of this study is to determine a survival analysis and identify the prognostic factors of medulloblastoma in children.

Methods: Fifty-five children with medulloblastoma were eligible for analysis between 1991 and 2015. We retrospectively reviewed clinical and histological data. Overall survival rate with clinical and histological factors were calculated using the Kaplan-Meier method. The Cox proportional hazard regression model was the estimated hazard ratio for mortality.

Results: The mortality rate was 49.1% in the present study. The median time follow-up was 68.8 months (range 1-294 months). A 5-year overall survival rate and median survival time was identified as 53.8% (95%CI 38.7-66.7) and 80 months (95%CI: 23-230), respectively. Univariate analysis revealed children younger than 3 years, hemispheric location, high risk group according to risk stratification and patients who did not receive radiation therapy affected the prognosis. In multivariate analysis, 2 factors influenced death: non-midline tumors (HR 2.54; 95%CI 1.11-5.80 ; p=0.02) and the high risk group (HR 3.86; 95%CI 1.28-11.60 ; p=0.01).

Conclusions: This study demonstrates the significance of tumor location and the high risk group (Age < 3 year-old,Residual tumor more than 1.5 cm2 and an evidence of metastasis) that are associated with prognostic factors. Interestingly, the survival rate of patients classified by location of medulloblastoma demonstrated contrasting results with previous clinical studies. However, these results bring into synchronization with molecular studies that WNT-subtype associated with midline medulloblastoma.

Patient Care: Tumor location is one of independent prognostic factor in his research.This study will give a supporting data to the future research on prognostic factor of the medulloblastoma.

Learning Objectives: By the conclusion of this session,participants should be able to :1)Describe the importance of prognostic factors in medulloblastoma.2) Discuss,in small groups about the risk and benefit of the treatment base on the natural history of the disease.3) Identify an effective treatment of the subclssification of medulloblastoma.

References: 1. McNeil DE, Cote TR, Clegg L, Rorke LB. Incidence and trends in pediatric malignancies medulloblastoma/primitive neuroectodermal tumor: a SEER update. Surveillance epidermiology and end results. Med Pediatri Oncol 2002;39:190-4. 2. Louis DN, OhgakiH, Wiestler OD, et al. editors. WHO Classification of Tumors of Tumours of the Central Nervous System. Lyon: IARC Press; 2007. 3. Fouladi M, Gajjar A, Boyett JM, Walter AW, Thompson SJ, Merchant TE,et al. Comparison of CSF cytology and spinal magnetic resonance imaging in the detection of leptomeningeal disease in pediatric medulloblastoma or primitive neuroectodermal tumor. J Clin Oncol 17:3234-7. 4. Packer RJ, Rood BR, MacDonald TJ. Medulloblastoma: present concepts of stratification into risk groups. Pediatr Neurosurg 2003;39:60-7. 5. Polkinghorn WR, Tarbell NJ. Medulloblastoma: tumorigenesis, current clinical paradigm, and efforts to improve risk stratification. Nat Clin Pract Oncol 2007;4:295-304. 6. Brandes AA, Paris MK. Review of the prognostic factors in medulloblastoma of children and adults. Crit Rev Oncol Hematol. 2004;50:121-8. 7. Taylor MD, Northcott PA, Lorshunov A,Remke M, Cho YJ, Clifford SC. Molecular subgroups of medulloblastoma: The current consensus. Acta Neuropathol 2012;123:465-72. 8. Kool M, Korshunov A, Remke M, Jones DT, Schlanstein M, Northcott PA, et al. Molecular subgroups of medulloblastoma: an international meta-analysis of transcriptome, genetic aberrations, and clinical data of WNT, SHH, Group 3, and Group 4 medulloblastoma. Acta Neuropathol 2012;123:473-84. 9. Shuangshoti S, Panyathanya R. Neural neoplasms in Thailand: a study of 2,897 cases. Neurology 1974;24:1127-34. 10. Janjindamai S, Vasknaonote P, Ratanalerd S, Phuenpathom N. Primary brain tumor in children at Songklanagarind Hospital: clinical profile and results of treatment. Songkla Med J 1997;15:15-22. 11. Sirachainan N, Nuchprayoon I, Thanarattanakorn P, Pakakasama S, Lusawat A, Visudibhan A, et al. Outcome of medulloblastoma in children treated with reduced-dose radiation therapy plus adjuvant chemotherapy. J Clin Neurosci 2011;18:515-9. 12. Gaur S, Kumar SS, Balasubramaniam P. An analysis of medulloblastoma: 10 year experience of referral institution in South India. Indian J Cancer 2015;52:575-8. 13. Muzumadar D, Deshpande A, Kumar R, Sharma A, Goel N, Dange N, et al. Medulloblastoma in childhood-King Edward Memorial hospital surgical experience and review: Comparative analysis of the case series of 365 patients. J Pediatric Neurosciences. 2011;6:S78-84. 14. Riffaud L, Saikali S, Leray E, Hamlat A, Haegelen C, Vauleon E, et al. Survival and prognostic factor in a series of adults with medullblastomas. J Neurosurg 2009;111:478-87. 15. Rutkowski S, voh Hoff K, Emser A, Zwiener I, Pietsch T, Figarella-Branger D. Survival and prognostic factors of earyly child hood medulloblastoma: an international meta-analysis. J Clin Oncol 2010;28:4961-8. 16. Jiang T, Zhang Y, Wang J, Du J, Ma Z, Li C. Impact of tumor location and fourth ventricle infiltration in medulloblastoma. Acta Neurochir 2016;158:1187-95. 17. Taylor MD, Northcott PA, Lorshunov A,Remke M, Cho YJ, Clifford SC. Molecular subgroups of medulloblastoma: The current consensus. Acta Neuropathol 2012;123:465-72. 18. Ellison, DW, Onilude OE, Lindsey JC, Lusher ME, Weston CL, Taylor RE. beta-Catenin status predicts a favorable outcome in childhood medulloblastoma: the United Kingdom Children’s Cancer Study Group Brain Tumour Committee. J Clin Oncol 2005;20:7951-7. 19. Gibson P, Tong Y, Robison G, Tompson MC, Currle DS, Eden C. Subtypes of medulloblastoma have distinct developmental origins. Nature 2010;23:1095-9. 20. Packer RJ, Vezina G. Management of and prognosis with medulloblatoma: therapy at a crossroad. Arch Neurol 2008;65:1419-24. 21. Dhall G. Medulloblastoma. J Child Neurol 2009;24:1418-30. 22. Gajjar A, Chintagumpala M, Ashley D, Kellie S, Kun LE, Merchant TE, et al. Risk-adapted craniospinal radiotherapy followed by high-dose chemotherapy and stem-cell rescue in children with newly diagnosed medulloblastoma (St Jude Medulloblastoma-96): long-term results from a prospective, multicentre trial. Lancet Oncol 2006;7:813-20. 23. Taylor RE1, Bailey CC, Robinson KJ, Weston CL, Walker DA, Ellison D,et al. Outcome for patients with metastatic (M2-3) medulloblastoma treated with SIOP/UKCCSG PNET-3 chemotherapy. Eur J Cancer 2005;41:727-34. 24. Zeltzer PM1, Boyett JM, Finlay JL, Albright AL, Rorke LB, Milstein JM. Metastasis stage, adjuvant treatment, and residual tumor are prognostic factors for medulloblastoma in children: conclusions from the Children's Cancer Group 921 randomized phase III study. J Clin Oncol 1999;17:832-45. 25. Massimino M, Antonelli M, Gandola L, Miceli R, Pollo B, Biassoni V. Histological variants of medulloblastoma are the most powerful clinical prognostic indicators. Pediatr Blood Cancer 2013;60:210-16. 26. Gilbertson RJ, Ellison DW. The origins of medulloblastoma subtypes. Annu Rev Pathol 2008;3:341-65. 27. Elaine Ron,Ph.D.Baruch Modan, M.D.,DR.P.H.,John D.Boice,Jr.,Sc.D.,Esther Alfandary, R.N.,Marilyn Stovall,M.P.H.,Angela Chetrit, B.S.,and Leah Katz, M.D.Tumors of the brain and nervous system after radiation therapy in childhood. N Engl J Med 1988; 319:1033-1039