Sandy Hutchens Cancer Prevention, August 26, 2009 – Tamoxifen is an estrogen-blocking drug. This class of medication is specifically designed to block the estrogen receptor to prevent the growth of breast cancer cells. But, unfortunately, not all breast cancers have the estrogen receptor. Those that don’t are usually more aggressive and metastasize more rapidly.
Researchers from Fred Hutchinson Cancer Research Center in Seattle looked at 728 women diagnosed with breast cancer. Those women were compared to 367 others diagnosed with both a first and second breast cancer.
The main finding from the study, published online Tuesday in the journal Cancer Research, was that tamoxifen lowered the risk of any second breast cancer overall by about half, said lead author Dr. Christopher Li.
“For the estrogen receptor-positive cancer, we have targeted therapy that again has been proven to again reduce mortality,” said Li. “That’s one of the reasons why ER-negative cancers are more worrisome because we don’t have a targeted treatment for them.”
Li said it’s important to remember that any treatment has risks and benefits associated with it, and tamoxifen is no exception.
Tamoxifen lowers breast cancer patients’ risk of dying of the disease, and has also been shown to lower a woman’s risk of developing a recurrent breast cancer and a second breast cancer, he noted. But use of tamoxifen also comes with risk of stroke, as well as the risk of endometrial cancer, he added.
“So here we’re finding that we’re adding potentially another risk to the risk-benefit equation,” Li said. “We’re finding that there is this increased risk in this more aggressive subtype of second breast cancer. However, we also overall found using tamoxifen did lower the risk of any type of second breast cancer overall.”
“For that reason, we don’t really think that this study changes the overall risk-benefit equation because the benefits for most women who are eligible to use this treatment are going to still outweigh the risks.”
Every tumour is a mix of receptor-positive and receptor-negative cells, she said. If the types of cells that predominate are receptor-negative, it gets read as an increased risk of receptor-negative breast cancer if tamoxifen is taken for five or more years.
Dr. Jay Harness,Tamoxifen And The Side Effects put up by Sandy Hutchens.
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