A team of researchers from the University of North Carolina recently found that Tamoxifen’s benefits for breast cancer prevention can compensate its risks of adverse effects. However, not all women appear to benefit from the drug.
Tamoxifen is a U.S. Food and Drug Administration approved drug for primary prevention of breast cancer. However, the drug is not usually recommended by clinicians as it increases the risks of adverse side effects.
Due to the lack of evidence concerning risk-benefit profiles in women using chemoprevention, Dr. Hazel B. Nichols and colleagues sought to assess the characteristics associated with initiation and suspension of tamoxifen for primary prevention of breast cancer in women with first-degree relatives diagnosed with the disease.
Those who participated in this research were part of The Sister Study, that enrolled 50,884 US and Puerto Rican women aged 35 to 74 years, between 2003 and 2009. The study entry criteria included women with no breast cancer but who had a sister with a breast cancer diagnosis.
From the total cohort, the researchers identified 788 women that were taking tamoxifen and 3131 non-users controls. From these women, the researchers collected at baseline data on tamoxifen use, initiation and cessation of use and total time of drug intake.
Data analysis performed with logistic regression revealed that 20% of women who used tamoxifen had insufficient evidence that its benefits compensate the risk of adverse effects. At 4.5 years, a total of 46% of women had suspended tamoxifen.
In a recent news release Dr. Nichols, Assistant Professor of Epidemiology in the University of North Carolina Gillings School of Public Health commented, “It’s important because it highlights that the estimated benefit is not the same for all women, and so women need to go and have a very specific conversation with their providers about what their health looks like at that time, and whether this is a reasonable option for them. Tamoxifen is very good at preventing breast cancer, but it also has to be weighed against an increased risk of uterine cancer, stroke or blood clotting negative effects,” he added.
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Based on these results, the research team concluded that both suspension of tamoxifen before five years of use and its use by women at risk of adverse effects may reduce the drug’s benefits for breast cancer prevention.
“I think we have seen that not all women who take tamoxifen for chemoprevention will have equivalent evidence that the risks outweigh the benefits, but the risk-benefit tool is easy to apply to estimate whether a woman’s benefits are likely to outweigh the risks,” Dr. Nichols concluded.
Thus, women and their clinicians should balance the risks and benefits of taking tamoxifen, as not all women may be eligible to take the drug.
The study titled “Risk-Benefit Profiles of Women Using Tamoxifen for Chemoprevention“, was published in the Journal of the National Cancer Institute.