Tumor irradiation blocks local angiogenesis, forcing any recurrent tumor to form new vessels from circulating cells. This phenomenon is particularly relevant in the context of glioblastoma, a highly aggressive and malignant brain tumor. The post-irradiation recurrence of human glioblastoma has been shown to be associated with the formation of new blood vessels, which are essential for the growth and survival of the tumor. Understanding the mechanisms underlying this process is crucial for the development of effective therapeutic strategies. The blockade of SDF-1 after irradiation has been identified as a key factor in inhibiting tumor recurrence, highlighting the importance of angiogenesis in the development and progression of cancer.