Medulloblastoma is a heterogeneous tumor.Molecular subgroup 3 is characterized by a dismal prognosis.Aim:to evaluate the treatment results among the patients of molecular subgroup 3 and to determine the factors affecting the prognosis.
We analyzed 103patients with medulloblastoma of molecular subgroup 3.In all the patients removal of the tumor was performed.Most of them had subtotal resection.All the patients got chemoradiotherapy according to the HIT protocol.Patients with stage M0 and classic variant got a reduced dose of craniospinal irradiation;those with MYC amplification and anaplastic/large cell medulloblastoma got CSI in standard doses.There were 32girls and 71boys.Most patients were over 3 years old:75compared to 28younger than 3.38 had M0,62-М+ and 3-Mx stage.MYC amplification was found in 19patients.MYCN amplification-in 4 patients.Classic medulloblastoma was in 68patients,anaplastic/large cell-in 35.
50(49%)are alive and 53(51%)died.Three patients(2.9%) had a secondary tumor:glioblastoma,anaplastic astrocytoma,osteosarcoma.The median observation time was 59 months(4 to 276 months).The five-year PFS was 0.52±0.05,the five-year OS was 0.51±0.04,and the 20-year OS was 0.47±0.05.The median survival was 84months, and the median PFS was 43months(4 to 276 months).There were no significant variations of PFS depending on the sex and age.The treatment results depended on the histological subtype:for classic medulloblastoma, the five-year PFS was 0.59;for the anaplastic/large cell subtypes-0.39(р=0.03833).The presence of metastases significantly affected the survival:PFS for stage M0 was 0.76;for stage М+,0.38 (р=0.00124).Patients with MYC amplification had a significantly worse survival compared to MYCN patients and those without MYC amplification:0.1, 0.75,and 0.61(р=0.00001).3patients with MYC amplification are alive:2 are recurrence-free, and 1 had a tumor recurrence after the treatment.Two recurrence-free patients had MGMT methylation detected.Among the patients with MYCN amplification,3 with classic medulloblastoma are alive,and one with anaplastic medulloblastoma died.
The results of treatment depended on the tumor subtype, presence of metastases, MYC amplification and MGMT methylation. In the absence of unfavorable factors, the survival was the same as in molecular subgroup4.