Only 1 in 7 Women at Risk for Breast Cancer Take Tamoxifen

Tim Locke

April 27, 2018

Only one woman out of seven with a family history of breast cancer decided to take tamoxifen as a preventive measure when it was offered, according to a small study from the United Kingdom.  The remaining six of seven women declined the offer.  

Tamoxifen taken prophylactically lowers the risk for breast cancer by at least 30% among women with a higher risk due to a family history of breast or ovarian cancer.

The drug was approved by the National Institute for Health and Care Excellence (NICE) for National Health Service funding in England as a preventive measure in 2013.

However, uptake has been unknown.

So researchers surveyed 732 women who were attending 20 centers in England between September 2015 and December 2016 to discuss their risk for breast cancer. They were approached to take part in a survey about preventive treatment, which also collected sociodemographic details.

The research team, from the University of Leeds, University College London, Queen Mary University of London, worked in collaboration with US colleagues from Northwestern University, Chicago, Illinois.

They found that of the baseline survey respondents (408 of 732; 55.7% response rate), the question on uptake of tamoxifen at 3-month follow-up was reported by 258 (63.2%).

Among these, only 1 in 7 women (38 of 258 [14.7%]) initiated tamoxifen preventive treatment. They had already started taking tamoxifen or had a prescription for tamoxifen from their general practitioner.

The results are published in Breast Cancer Research and Treatment.

Family commitments and priorities appeared to have a significant effect on decision making. Women who had children were more likely to say they  took tamoxifen than did those who did not have children (odds ratio, 5.26; 95% confidence interval, 1.13 - 24.49; P = .035). A person's attitude toward medication and side effects, as well as the attitudes of others, sometimes played a role, as did women's approach to risk.

However, no sociodemographic differences were found in uptake.

Sixteen women participated in semi-structured interviews, and this gave some insight into the women's answers to the survey questions.

One 38-year-old woman who was married with two children said, "I'm not necessarily going to get breast cancer, but if [tamoxifen] can prevent it, I would be willing to take it, definitely. Obviously I've got young children to think about now. I would be happy to start taking it, but yes, I do look at the side effects."

A 47-year-old married woman with no children took a different approach: "I come from a family of people who don't take tablets, and who definitely don't take tablets on a regular basis."

"They're bad, that's the general feeling about tablets.  There's something about willpower in it as well, you don't need to take a tablet. You just need to grit your teeth and get through it," she is quoted as saying.

Feelings of fear, anxiety, and denial were also explored, with one woman saying: "I always felt…I would develop breast cancer.  I was 8 when [my mother] died…. It's very magical thinking about, well, if I'm going to get it, I'm going to get it, and it doesn't matter what I do. That it's kind of written in the stars…that it's my fate.  So, what then would have been the point of any breast cancer prevention?"

The researchers write: "Women were more likely to initiate tamoxifen if they had children because a reduction in risk meant they would be healthier for longer and thereby more able to care for their families."

"Women weigh up the risks and benefits of preventative therapies within the context of other commitments and priorities, including their family and children. Encouraging women to discuss their beliefs and perceptions about preventative therapies within the consultation may help support informed decision-making," they conclude.

Study limitations included reliance on accurate self-reporting and the risk for selection bias in response and retention rates. The researchers say confidence intervals were wide for the association between having children and tamoxifen uptake. Raloxifene treatment may have been discussed in some centers, although tamoxifen is the most widely offered drug. Also, some women may not have made a final decision about starting treatment before the 3-month follow-up interview, the researchers note.

Discussing Concerns

In a news release, Samuel Smith, PhD, study author from the University of Leeds, and a behavioral scientist, said, "While it's reassuring a woman's background doesn't seem to be a barrier to taking tamoxifen, only 1 in 7 of those at increased risk of breast cancer are taking up the option. Therefore it's important doctors can discuss women's concerns and provide information to help them while they are considering their options.

"Further research is needed to understand if all women eligible to take tamoxifen for prevention are getting the help and support they need," he added.

Commenting on the study findings in a statement, Richard Roope, MD, Cancer Research UK's senior clinical adviser and GP expert, said, "It's valuable to understand why women might reject tamoxifen, and this research highlights there are a range of complex reasons behind the decision.

"It's vital more work is done to understand these barriers, improve treatments and ensure doctors are getting the support they need to help women decide whether preventative medication is right for them."

The charity Breast Cancer Care also issued a statement commenting on the findings. The charity's clinical nurse specialist, Carolyn Rogers, said, "While it is vital women with a high risk of breast cancer are offered tamoxifen, there is a bigger, more complex picture.

"We know the drug may help reduce risk but it also comes hand in hand with side effects, including menopausal symptoms like hot flushes and low libido, which can severely disrupt day-to-day life. And other options, such as risk-reducing surgery or regular screening to detect breast cancer early, can be more practical and preferable for some individuals.

"The most important thing is that women with a high risk of breast cancer are given clear, comprehensive information so they can make the choice that is right for them."

Among the authors, Julia Hackett has received research funding and honoraria from AstraZeneca. Rachael Thorneloe has received honorarium from Novartis. The other authors have disclosed no relevant financial relationships.

Breast Cancer Res Treat. Published online April 24, 2018. Abstract

Follow Medscape Oncology on Twitter: @MedscapeOnc

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