The role of paclitaxel in the treatment of primary and metastatic brain tumors.

The rationale for the use of paclitaxel to treat brain tumors includes impressive activity in a wide array of chemotherapy-resistant solid tumors, in vitro and in vivo evidence of cytotoxicity against primary brain tumors, and a paucity of effective alternative agents. A review of published studies evaluating paclitaxel alone or in combination with other chemotherapeutic agents suggests that paclitaxel alone is not highly active against newly diagnosed or recurrent glioblastoma multiforme. However, additional prospective trials are warranted to evaluate the efficacy of paclitaxel plus conventional cranial irradiation or stereotactic radiosurgery. Single-agent paclitaxel appears to be active against gliomas with an oligodendroglial component and may prove useful both as a component of initial therapy and for recurrent disease. Activity against anaplastic gliomas and brain metastases also should be explored. With radiation, a weekly paclitaxel administration schedule is particularly appealing from pharmacologic, safety, and dose-intensity perspectives. In addition, the dose of paclitaxel must be increased in patients who are concurrently receiving medications that induce the P-450 drug metabolizing system. Primary and metastatic brain tumors constitute a very difficult problem in oncology. Future investigations should be directed at evaluating paclitaxel-based chemotherapy regimens in selected brain tumor types, combining paclitaxel with stereotactic radiosurgery, and determining the importance of other proposed mechanisms of action of paclitaxel (eg, inhibition of angiogenesis and tumor invasion).