目的　评价分析<3岁儿童髓母细胞瘤HIT 2000 方案的治疗效果及预后。方法　回顾分析采用HIT 2000 方 案治疗的<3岁髓母细胞瘤患儿的临床资料。结果　共纳入38 例<3岁髓母细胞瘤患儿，完全缓解8 例、部分缓解5 例、 疾病稳定6 例、疾病进展或复发19 例。5 年无事件生存率、总体生存率分别为（43 . 9 ± 8 . 8）%、（ 49 . 5 ± 9 . 1）%； M0组和M+组，DMB/MBEN组和CMB、LC/A 组，SHH组和G4组之间3 年或5 年无事件生存率和总体生存率差异均 有统计学意义（P 均< 0 . 05）；而R0组和R+ 组、放疗组和未放疗组之间的5 年无事件生存率和总体生存率差异均无统 计学意义（P 均>0.05）。13 例患儿行放疗，放疗期间均未出现放射性脑坏死及继发第二肿瘤，1 例出现放射性肺损伤。所 有患儿均化疗，化疗期间均出现不同程度的骨髓抑制，肝功能损害3 例，口腔黏膜溃疡5 例，经对症处理后预后良好。没有 患儿因放、化疗而死亡。结论　HIT2000 方案治疗3 岁以下儿童MB疗效较好，疾病预后与M分期、病理分型及分子分型 有关，化疗耐受可，可作为3 岁以下儿童MB治疗方案之一。

Objective　To assess the effect and toxicity of HIT2000 treatment and prognosis factors in children medulloblastoma (MB) under 3 years old. Methods　The MB patients younger than 3 years were selected and they were received HIT2000 protocol. The effect and relapse/metastasis rate, toxicity reaction during radiotherapy and chemotherapy were summarized. Prognosis factors included pathological types, molecular types, radiotherapy, tumor resection and M stage were analyzed by Kaplan-Meier and tested by Log-Rank. Results　A total of 38 patients were admitted, in which 8(21%) were completely relieved, 5(13%)were partial relieved, 6(16%) were disease stable,19(50%) were prognosis/relapse. 13(34%) patients died and 25(66%) alive. 3 or 5 years EFS rate and OS rate were 43.9±8.8% and 49.5±9.1%, respectively. The 3 or 5 years EFS rate and OS rate showed significant difference among various pathological types, molecular types and M stage (P<0.05). However, no difference was observed among groups with tumor resection, with or without radiotherapy (P>0.05). Thirteen（34%）patients received radiotherapy, none of them found with radiation encephalic necrosis and secondary tumor. One (8%) experienced radiation lung injury. All patients received chemotherapy had different grades of bone marrow suppression, and 3(7%)patients with liver dysfunction, 5(13%) with oral mucosal ulcer. Finally all damages were cured after treatment. No treatment-related deaths occurred. Conclusion　HIT2000 protocols are suitable for childhood MB younger than 3 years old, and disease prognosis are related to M stage, pathological types and molecule types, side-effect of chemotherapy and radiotherapy are endurable. This protocol can be an optional program for MB in children under 3 years old.