What are the best treatments for an aggressively growing brain tumor?

Depend on tumor type: Treating for growing tumors depends on the type of tumor, location and what treatments have already been tried. Combinations of surgery, radiation and chemotherapy are common.

GBM therapy: Best know exact tumor type. By aggressive brain tumor I am presuming you mean a primary brain tumor known as glioblastoma multiforme(gbm). Treatment includes maximum safe resection+/-bcnu wafer and based on performance status- radiation + temazolamide. Stupp r et al. Radiotherapy + concomitant and adjuvant temozolomide vs radiotherapy alone, lancet oncol 2009.