Gliomas are one of the most common tumors of the central nervous system, which cause significant morbidity and mortality. Glioblastoma (GBM) is an aggressive and debilitating disease, which is the most common primary brain tumor in adults. Despite optimal surgical resection followed by radiotherapy and adjuvant chemotherapy, prognosis of patients with GBM remain poor. Tumor-treating fields (TTFields), as a novel treatment approach, is being explored through increased clinical application. Herein, we report the case of a 46-year-old man who was diagnosed as anaplastic astrocytoma [World Health Organization (WHO) III grade], IDH1 R132 mutation, IDH2 R172 mutation, and a methylated MGMT promoter, without 1p36 and 19q13 heterozygosity loss. About 2.5 months after surgery, the patient presented with seizures, aphasia, and memory loss. Following the first-line treatment, TTFields was shown to be a valuable treatment option to control clinical symptom burden. The use of TTFields was shown to prolong progression-free survival and delay the pathological upgradation to glioblastoma. Notably, combined TTFields and chemotherapy might be beneficial in terms of risk reduction for pathological upgradation. To the our current knowledge, this is the first case report that attempts to offer possible strategies based on TTFields toward delaying pathological upgradation from anaplastic astrocytoma (WHO III grade) to glioblastoma.