Responses to new research linking breast cancer and HRT

The Primary Care Women’s Health Forum (PCWHF), Royal College of Obstetricians and Gynaecologists (RCOG), and British Menopause Society (BMS) have all issued responses to the new research linking breast cancer to HRT.

The PCWHF said:

“The latest paper in The Lancet on breast cancer risks and hormone replacement therapy (HRT) is from the same group who have published repeatedly on this topic for over 20 years. It should be seen as another piece in the jigsaw rather than changing the picture.

“Biological science tells us that most breast cancers are hormone responsive. Epidemiological studies such as this illustrate a population effect. The Lancet paper confirms that vaginal oestrogen does not have an influence but systemic HRT increases breast cancer diagnosis. The size of this effect is linked to duration of use and that a combination HRT including a progestogen has more impact than oestrogen alone. The addition that this paper provides is the suggestion that continuous progestogen is associated with a greater increase than cyclical use. This does not prove that the increase is caused by this factor, there may be other clinical considerations. Older women are more likely to be prescribed continuous combined HRT. It does not provide balance with the endometrial cancers avoided by a continuous regimen.

“Healthcare professionals treat people as individuals not populations.  Women need accurate and balanced information to understand what it means for them. These breast cancer figures need to be seen in proportion and context.

“Women should understand that HRT has no greater effect than the hormones that drive their periods. Breast cancer is more likely to occur as women get older – after menopause. If a woman has an early breast cancer, then exposure to these hormones can increase its rate of growth. The size of this effect varies with the type, dose and duration of the regimen used. Other lifestyle choices will also increase breast cancer growth: two units of alcohol a day have an effect which is comparable to that of standard dose combination HRT. Obesity increases breast cancer growth as well as multiplying many other risks. HRT shows no additional effect on breast cancer in obese women – the influence is already present.

“Women need to assess the impact that their symptoms are having on their quality of life. They should consider the effect on their family, their ability to work and the value that relief would represent. They need to understand that while longer duration of hormone exposure might increase breast cancer growth, attendance for screening allows early diagnosis and better treatment outcomes. They need also to factor in the avoidance of fracture, heart attacks, bladder infections and other proven benefits of HRT and make a decision that is appropriate for them and review it annually.“

In a joint statement, the RCOG and BMS said:

A study published in The Lancet shows the risk of breast cancer with hormone replacement therapy (HRT) in relation to the type and timing of hormonal intake.

The overall findings are in keeping with The National Institute for Health and Care Excellence (NICE) guidance on treatment of menopausal symptoms which notes a small increased risk of breast cancer associated with HRT.

The review covered the period January 1992 to January 2018 and included information from 58 studies of 108,647 postmenopausal women who developed breast cancer of which 55,575 (51%) had used HRT.

The report showed an increase in the risk of breast cancer with HRT intake. The risk of breast cancer was noted to be higher with combined estrogen / progesterone compounds, but was also increased, although to a lesser extent, with estrogen only systemic HRT.

The risk of breast cancer remained elevated for more than 10 years after discontinuing HRT and this appeared dependant on the duration of HRT use. Starting HRT between the age of 40 and 50 was also associated with an increased risk of breast cancer, but the number of women in this sub-group was relatively small.

Professor Janice Rymer, Consultant Gynaecologist and Vice President of the Royal College of Obstetricians and Gynaecologists, said:

“Women and doctors should be reassured that the findings of this study do not add anything new in terms of the effects of hormone replacement therapy. Research shows that, for most women, HRT helps to manage menopausal symptoms and is safe.

“Women must be informed of the small increase in risk of breast cancer so they can weigh these up against the benefits that they may have from taking HRT. Every woman experiences the menopause differently and symptoms vary. These can be extremely debilitating and have a significant impact on a woman’s physical and psychological health, career, social life and relationships. Unfortunately, many women are still suffering in silence and are reluctant to seek advice and support due to concerns around the risks of breast cancer associated with HRT.

“The findings from this research should be helpful to both women and doctors, particularly around when considering whether to start hormone therapy, for how long and which preparation they could take – whether it includes oestrogen and progestagen combined, or oestrogen alone. These findings should not put women off taking HRT if the benefits – such as protection of bones and decrease in cardiovascular risk – outweigh the risks.

“To put the risk into context, a woman has greater risk of developing breast cancer if she is overweight or obese compared to taking HRT. Women must be aware of the effect of obesity and alcohol which increase the risk of breast cancer and modifies the additional risk of HRT.”

Mr Haitham Hamoda, Chair of the British Menopause Society, said:

“We welcome this further data on the incidence of breast cancer which will help us counsel our patients and women in general better. This paper provides further data on the impact of estrogen and progesterone combined and estrogen that adds more detail to that we have already gathered from overall assessment of the literature. It also includes some new information on different types of progestogen that surprisingly were found to not vary as much as had been thought.

“Of particular interest though is the impact of estrogen, and different regimens of combined HRT on obese women, where the former is found to have little effect but the increase with the latter is greatest with continuous combined HRT. However, in practice this must be weighed against the rapidly rising incidence of endometrial cancer which is significantly decreased by the continuous combined preparations.

“The overall findings from this study are in keeping with the NICE menopause guideline recommendations which show a small increase in risk of breast cancer with HRT. Women must be informed of the data on breast cancer risk with HRT to help them make an informed decision. This should also be considered in comparison to the risk of breast cancer with other lifestyle factors such as alcohol intake and obesity which have been shown to be associated with a higher risk compared to that with HRT. This should also be taken in the context of the overall benefits obtained from using HRT including symptom control and improving quality of life as well as considering the bone and cardiovascular benefits associated with HRT use.’’

Source: The BMS