Only 1 in 7 high-risk women take breast cancer prevention drug

Tuesday April 24 2018

"Nearly 90% of women at risk of breast cancer shun preventative drugs due to fear of side effects and 'fate'," reports the Independent Online.

Current guidelines recommend that women thought to be at increased risk of developing breast cancer because they have a family history of the condition should be offered a drug called tamoxifen.

Tamoxifen can reduce this risk, but the drug, which women usually have to take every day for 5 years, can cause side effects such as hot flushes, tiredness and nausea.

A new study looked at 258 higher-risk women who had been recommended tamoxifen and referred to a specialist centre in England.

The researchers found only around 1 in 7 women (14.7%) decided to take tamoxifen.

Of the 258 women, 16 agreed to take part in follow-up interviews explaining the reasons why they did or didn't decide to use tamoxifen.

The researchers found women with children were more likely to agree to treatment.

Common reasons given for turning down treatment was a reluctance to take medication on a long-term basis, and the belief that whether or not they developed breast cancer was down to "fate".

The National Institute for Health and Care Excellence (NICE) has produced a series of decision aids that outline the pros and cons of preventative treatment for people with a family history of breast cancer.

It's important to stress that tamoxifen is not something most women should take: it's only suitable as a preventative treatment for women with a moderate to high risk of breast cancer who haven't yet been through the menopause.

Where did the story come from?

The study was carried out by researchers from several institutions in the UK and US, including University College London (UCL) and Northwestern University in Chicago.

No external sources of funding were reported. But individual authors did report conflicts of interest for receiving research funding from drug companies such as AstraZeneca and Novartis.

The study was published in the peer-reviewed journal Breast Cancer Research and Treatment. The study has not yet been made available on the internet.

Generally, the UK media coverage of this study was balanced, covering the different reasons affecting women's use of prevention therapy.

But some simplistic headlines, such as The Sun's "Tamoxifen costs just 6p a day and can cut the chance of the disease by a third", could mislead readers into thinking all women would benefit from taking tamoxifen: the drug is only recommended to a small minority of women.

What kind of research was this?

This cross-sectional study aimed to better understand uptake rates of preventative therapy for women with an increased risk of developing breast cancer.

The researchers approached women with a family history of breast cancer who were attending an appointment at a specialist centre in England.

The women were asked to complete surveys or interviews so the researchers could understand how many took preventative treatment for breast cancer and the reasons behind this.

But observational studies like this one can only provide us with insights – they can't give definite answers.

What did the research involve?

The study included women with a family history of breast cancer referred for an appointment at one of 20 centres across England between September 2015 and December 2016.

It included women aged 18 and over who'd been assessed as having a moderately high or high risk of breast cancer, who were therefore eligible for tamoxifen.

Following their appointment, participants were either assigned to a survey study or interview study.

A total of 732 women were approached: 258 completed surveys and 16 agreed to an interview.

The survey was completed at the start of the study, with a follow-up questionnaire sent at 3 months.

The initial survey asked about:

  • marital status (single/divorced/separated/widowed)
  • ethnicity (white groups/others)
  • education level (degree level/below degree level)
  • employment (full time/part time/other)
  • self-reported health (poor/fair/good/excellent)
  • age less than 35 years; 36 to 49 years; and more than 50 years)
  • whether they had children or not

They were also categorised according to the Index of Multiple Deprivation scores into categories ranging from most deprived to least deprived.

In the 3-month follow-up survey, women were asked about their feelings towards taking tamoxifen using the following statements:

  • I decided immediately that I did not want to take tamoxifen.
  • After some thought, I decided that I did not want to take tamoxifen.
  • I met with my GP to talk about tamoxifen, and decided against taking it.
  • I met with my GP to talk about tamoxifen, but they would not prescribe it.
  • I have a prescription for tamoxifen from my GP.
  • I am currently taking tamoxifen.

Women were classified as taking tamoxifen if they responded using the last 2 statements.

In the interview study, women were asked to participate in face-to-face interviews around 35 minutes in length. Overarching themes were developed from the analysis.

What were the basic results?

Survey data

The 258 women who completed the surveys had an average age of 45.

The majority of these women had children and were of white ethnicity, educated below degree level, married or cohabiting, and in full-time employment.

Uptake of tamoxifen in this group was 14.7% – about 1 in 7. Women with children were more likely to take preventative therapy than those without (17.6% versus 3.8% respectively).

This was a statistically significant result (odds ratio [OR] 5.26, 95% confidence interval: 1.13 to 24.49), though the wide confidence intervals indicate the degree of uncertainty around how much this influences decisions.

No other factors affected uptake of tamoxifen.

Interview data

From the 16 interviews, researchers described the following themes affecting the decision-making process of these women:

  • Considering children in making decisions – women thought of their children, not just themselves, when considering whether or not to take preventative treatment. They were aware of the side effects and the impact on their immediate family life.
  • Impact of other people's beliefs about medication – women were influenced by the attitudes and beliefs of their familial support systems towards the medication. For example, if there was a culture of a negative attitude towards medication, women were less likely to initiate treatment. They were also influenced by past experiences of family members who had previously used tamoxifen and their personal success with this treatment.
  • Emotional response to risk – women had different emotional responses to cancer risk, such as anxiety, fear and denial, and feeling like they had a lack of control over it.

How did the researchers interpret the results?

The researchers concluded: "Uptake of tamoxifen is low in clinical practice. There were no sociodemographic differences in uptake, suggesting that the introduction of breast cancer preventative therapy is unlikely to create socioeconomic inequalities in cancer incidence.

"Women's decision-making was influenced by familial priorities, particularly having children."

Conclusion

This valuable study investigated the reasons behind uptake of preventative hormone therapy for women assessed as having a high risk of developing breast cancer.

A couple of notable themes emerged. For example, researchers found that socioeconomic factors didn't seem to have an influence, but women were influenced by other family members and took into consideration any children they had.

As the researchers rightly say, the study highlights the need for a thorough consultation between high-risk women and the specialist healthcare professional, discussing their beliefs and perceptions around preventative therapies so they can make a fully informed decision.

But there are a few points to note. The study explores the views of a relatively small number of women – particularly the interview, which only looked at 16 women. These views can't be taken to represent the views of all women at high risk of breast cancer.

Most (97%) of the women in this study were white, so the results may not be representative of the views of women of different ethnicities.

Also, this study only had a 3-month follow-up period. It's recommended that tamoxifen is taken for 5 years, so the study wasn't able to capture data on women who may stop their prevention therapy further down the line.

Finally, it's worth pointing out that this story is relevant to only a very small proportion of women in the UK.

For most women, there are other, more suitable, ways to lower their risk of breast cancer, such as breast awareness, advice about hormonal contraceptives or HRT, and attending screening appointments.

Analysis by Bazian
Edited by NHS Choices