Recurrence pattern and Survival analysis in patients undergoing radiotherapy IMRT technique for medulloblastoma

Abstract Objective The technique of radiotherapy is associated with the recurrence pattern and prognosis of postoperative treatment for medulloblastoma. Our aim was to assess recurrence patterns and survival in patients with medulloblastoma between three-dimensional conformation (3D-CRT) and intensity modulated radiotherapy (IMRT). To analyze the factors affecting the prognosis, such as the use of 3D-CRT or IMRT, the time interval of surgical and radiotherapy, whether there is chemotherapy and chemotherapy regimen.Methods In this study, 36 patients with medulloblastoma were conducted investigating and data were analyzed from May 2009 to September 2017. The median survival of each group was calculated for different clinical stages,pathological types and treatment methods. The PFS and OS for patients curves were derived by Kaplan-Meier estimation, and which were calculated using the Cox proportional hazards model between the IMRT and 3D-CRT treatment groups.Results Up to the follow-up date, 7 of the 9 patients in the 3D-CRT group had recurrence and 9 of the 27 patients in the IMRT group had recurrence. The 2-year and 5-year PFS of the IMRT group were 74.1% and 65.8%, and which of the 3D-CRT group were 55.6% and 22.2%, respectively. The PFS was significantly higher for patients treated with IMRT compared with 3D-CRT (P<0.05). The 2-year overall survival rates of the IMRT group compared with the 3D-CRT group were the same, the 5-year overall survival rate of the IMRT group was higher than that of the 3D-CRT group, however, there was no statistical difference. The PFS and OS for patients with low-risk groups were better than those of the high-risk group (P<0.05). There was no statistical difference between the M2 group and the M3 group in the 2-year and 5-year OS(P>0.05). There was no statistical difference in the chemotherapy-free group, the EP chemotherapy regimen and the temozolomide (TMZ) chemotherapy group in the 2-year and 5-year PFS and OS(P>0.05). The results of multivariate Cox proportional hazards model analysis showed that the residual, recurrence or metastasis before radiotherapy were independent prognostic factors affecting PFS(P<0.05). Radiotherapy mode was negatively correlated, although there was no statistical significance(P=0.061).Conclusions IMRT can reduce the risk of spinal cord recurrence compared with 3D-CRT, especially the low rate of spinal cord recurrence. The development of the technique of radiotherapy was associated with improvements in medulloblastoma prognosis.