Abstract:

Objective To explore the impacts of 3D conformal radiation therapy（3D⁃CRT）or intensity⁃ modulated radiotherapy（IMRT），time interval from surgery to radiotherapy，and use of chemotherapy on the recur⁃ rence pattern and survival. Methods The data on 36 patients with medulloblastoma who had been treated from May 2009 to September 2017 were analyzed. The impacts of different clinical stages，pathological types，and treat⁃ ment methods on the survival stage were analyzed in each group. The Kaplan ⁃Meier method was used to compare the survival differences between differentgroups. Results Seven of the 9 patients in the 3D ⁃CRT group and 9 of the 27 in the IMRT group had recurrence. The 5⁃year progression⁃free survival（PFS）rate was significantly higher in the IMRT group than in the 3D⁃CRT group（65.8% vs. 22.2%，P < 0.05），but there was no statistical difference in the 5⁃year overall survival（OS）（62.1% vs. 44.4%，P > 0.05）. The PFS and OS were better in the M0 group than in the M2/M3 groups（P < 0.05）. The PFS of surgery to radiation interval time < 12⁃week group was superior to that of the > 12⁃week group（P < 0.05）. In the multivariate Cox proportional hazards analysis，residual lesions， recurrence，or metastasis before radiotherapy were independent prognostic factors for PFS（P < 0.05）. Conclusions IMRT has a lower risk of spinal cord recurrence than 3D ⁃ CRT. The interval between surgery and radiotherapy should be shorter than or equal to 12 weeks. The PFS and OS were higher in patients without residual lesions ， recurrence，and spread before radiotherapy.

Key words:

medulloblastoma, overall survival, progression?free survival, radiation therapy