Tamoxifen – a drug commonly used for treating breast cancer – may actually increase the severity of the disease, according to
Dr Christopher Li at the Fred Hutchinson Cancer Research Centre.
Their research compared breast-cancer patients who received the estrogen-blocking drug tamoxifen to those who did not, and found that while the drug Tamoxifen was associated with a 60 percent reduction in estrogen receptor-positive (ER positive) second breast cancer – the more common type, which is responsive to estrogen-blocking therapy) – it also appeared to increase the risk of ER negative second cancer by 440 percent.
“This is of concern, given the poorer prognosis of ER-negative tumors, which are also more difficult to treat,” said Dr Christopher Li.
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