<prompt> Answer this question truthfullyWhat is gemistocytic astrocytoma? This is already a proper English sentence and does not require any rephrasing.  <response>: <reason> Chemotherapy is recommended for patients with recurrent or de-differentiated gemistocytic astrocytomas.The predominant therapy for gemistocytic astrocytoma is surgical resection. Adjunctive radiation and nitrosourea -based chemotherapy may be required. Surgery: Since gemistocytic astrocytoma can behave aggressively, surgery is the mainstay of treatment. Radiotherapy: Radiotherapy may be used in gemistocytic astrocytoma post-operatively or at the time of recurrence or progression. Chemotherapy: Chemotherapy may have a role in recurrent and de-differentiated tumors.There are no measures for the primary prevention of gemistocytic astrocytoma.There are no measures for the secondary prevention of gemiistocytic astrocytoma. 