Tamoxifen is most commonly associated with chemotherapy of breast cancer but has been used recently to treat other cancers including brain tumors
The mechanism of its action is complex involving several sites in and on cells. Current opinion suggests that its key role in malignant glioma is to inhibit a cell signaling enzyme called protein kinase C. It does this in a dose-dependent manner and consequently is administered at a much higher dose for brain tumor sufferers than is given to breast cancer patients. It has a low toxicity and its side effects are minimal. There is evidence to suggest that it should not be used in conjunction with the anti-epileptic (anticonvulsant) phenytoin. It has been used on its own and in conjunction with other drugs (adjuvant chemotherapy). Although tamoxifen does not improve all instances of brain tumor, there is considerable evidence that it is of benefit to many.A new non-invasive procedure may be able to detect those patients who will respond to tamoxifen.