If tamoxifen's effectiveness were the only question, our alarm would not be so great. Tamoxifen triples the risk of uterine cancer, even in patients followed for relatively short periods. This is acknowledged by the drug's manufacturer. Inc. The prestigious British Medical Research Council warns of the absence of any safety margin at the trial dose. Yet the NCI misleadingly trivializes evidence of liver cancer in rats and ignores reports of two liver cancers in women just double the dose used in the trials.
Tamoxifen also promotes liver cancer in rats previously exposed to low doses of other carcinogens.
Indeed, it is probable that a significant number of healthy women receiving tamoxifen may die from liver cancer after a decade or so. Previously undisclosed similar evidence has just been obtained from the U.S. Food and Drug Administration. Sometimes-severe menopausal symptoms, including hot flashes and vaginal discharge, are other recognized complications that the NCI seeks to downplay. The consent form exaggerates tamoxifen's possible and questionable benefits and trivializes probable and high risks. The consent form's waiver of compensation for illness and injury, which participants must sign, is unlikely to protect the NCI or its investigators and hundreds of U.S. and Canadian centers and institutions involved in the trial from a future flood of malpractice and punitive claims for cancer and other complications.