HT & Breast Cancer
Note: Hormone therapy (HT) may also be referred to as hormone replacement therapy (HRT).
Questions and answers
The Women’s Health Sectrets answers your questions about the report on breast cancer from the Lancet 9 August 2003.
For expert comment about the report
Breast Cancer and hormone-replacement therapy in the Million Women Study – Comment
What is the significance of this new study?
This observational study of women who had been using hormone therapy (HT) for about six years prior to recruitment, calculates a similar increase in risk of breast cancer as reported in the overall figures from the Women’s Health Initiative (WHI) study released in July 2002. That study reported no increase in breast cancer risk over seven years in women who had not taken HT prior to study entry, but an apparently increased risk in prior users of oral combined HT (conjugated equine oestrogen and medroxyprogesterone acetate) compared with non-users.
In the study published in the Lancet the authors calculated the following:
- For 1,000 women who go through menopause aged 50 and who have no HT, we would expect 27 breast cancers to be diagnosed in this group by the age of 55 years.
- If the 1000 women had five years of combined oral HT, we would expect a total of 34 breast cancers (an extra seven cancers).
- In a previous study the authors state that the risk associated with taking HT between 50 and 55 years is equivalent to the effect of menopause being delayed until the age of 55 years.
What new information is presented in this study?
This study also indicates a smaller but statistically significant increased risk of breast cancer for women taking oestrogen only with no difference between the type of formulation (oral versus transdermal patch).
- If 1000 women took oestrogen only there would be a total of 28.5 breast cancers (an extra 1.5 cases). An increase in risk, similar to that of oestrogen only was also observed for progesterone alone and tibolone.
What does this report mean for Australian women?
These findings provide further information about the risk of breast cancer with hormone therapies including patches, implants and tibolone.
The authors have previously noted that studies such as this one where patients choose their own treatment are subject to bias and advised caution in the interpretation of the findings (British Journal of Obstetrics and Gynaecology 2002; Vol 109, Pg 1319). These findings need to be evaluated in randomised trials.
HT in Australia is prescribed for the management of symptoms that significantly impair a woman’s quality of life. Based on the findings of this study, continued use for this purpose remains appropriate where the woman is fully informed about the associated risks.
The commentary made on this report in the Lancet has talked, quite inappropriately, about HT as preventive therapy. This is no longer the recommended use of HT.
Are these findings relevant for all hormone treatments?
Yes, because no treatment is without risk (this includes non-hormonal and alternative therapies) and all women prescribed HT should be regularly reviewed.
Are ‘bioidentical hormone therapies’ a safe alternative?
These are simply the same hormones given in a different way and we would expect to convey the same risk. Some health professionals are promoting ‘bioidentical’ hormone therapy not only as safe but also as preventing cancer.
There is no published evidence that this is true and women should be cautious about taking any hormonal preparations that have not been subjected to careful research evaluation.
Should all women stop hormone therapy?
The new findings may indicate a small increase in risk of breast cancer with use of hormone therapy for six years or more. As previously recommended women taking this therapy for the management of severe menopausal symptoms need to balance their need for symptom relief with the long-term increased risk of breast cancer.
Women who are concerned should consult their health professional to discuss their individual risks and benefits.
Does HT cause breast cancer?
The evidence from the WHI study which is a randomised trial suggests that long-term use of combined oral therapy in prior users of the therapy, but not in first-time users, increases the risk of breast cancer. We need to be cautious in our interpretation of the data about other forms of HT.
This new study is not a randomised trial. Women taking other forms of HT may be on those treatments for reasons that could increase their risk of developing breast cancer. This could bias the results of the study.
Does tibolone cause breast cancer?
This is the first report of any association between tibolone (Livial) and breast cancer but it is not a randomised trial. Women at higher risk of breast cancer in the UK were more likely to take tibolone and this would bias the findings.
Why do doctors continue to treat women with HT?
Many women experience severe symptoms that substantially impair their quality of life. As long as women are aware of the small increase in breast cancer risk they have the right to choose hormone therapy.
Should HT be suspended until we know more?
No. HT may be prescribed for clear indications, to a woman who is fully informed of any risk and who has regular review.
Do women using hormone therapy need more mammograms and other investigations?
There is no simple answer to this question, as past history and family history all need to be taken into consideration. This study reinforces the importance of regular mammograms, annual clinical examination with a GP and breast self-examination so women become familiar with their own breasts.
What are the current recommendations for mammography screening in Australia?
Mammography screening is the best way to detect breast cancer at its earliest stages among women in the over 50 age group. Mammographic screening is recommended every two years for women aged 50-69 without breast symptoms or a strong family history, as this is when screening has shown to be most effective.
- It is very important that women who develop anything that feels like a lump in their breast or any changes consult their doctor as early as possible.
- The result of a mammogram must be interpreted in conjunction with a physical examination, taking into account age and personal family history.
How can women make an informed decision about using HT?
To greatly assist in comparing treatment and deciding what is right for you, ask yourself a series of questions:
- How much do my symptoms impact on my quality of daily life?
- What would happen if I did nothing?
- What treatment / intervention choices are available to me?
- What are the possible benefits or risks of different choices?
- How reliable is the evidence for the proposed benefits or risks of any therapy? (Be sure of seeking evidence from RELIABLE sources).
- How do the benefits and risks weigh up for me?
- Have I now gathered enough information to make my decision?
Women need to assess the choices available based on best evidence from clinical trials against:
- Resources available, cost and access to services.
- A woman’s personal values.
What should women ask their health practitioners?
It is important to visit a health practitioner with some questions already planned. Write the questions down. This will promote clear and concise communication between a woman and her practitioner. It is often a good idea to book a longer consultation time.
Some examples may be:
- Are the findings of this study relevant to my situation and my treatment?
- What treatment / intervention choices are available to me?
- What are the possible benefits and risks of the different choices?
- What might happen if I stop taking my HT immediately?
- Where else can I gather information? (websites, services, printed material)
- How often does my treatment need to be reviewed?
- Do I need to have a mammogram?
- Should I stop my HT prior to having a mammogram?
- What will happen if I have an abnormal mammogram?
Where to from here
- All women over 50 years should attend for regular mammographic screening, regardless of whether they are on HT or not.
- Short-term use of hormone therapy (for the management of menopause symptoms that unacceptably impair a woman’s quality of life) is a safe and effective option. But the benefits and risks need to be weighed up by each individual woman.
- Women who have prolonged symptoms may choose to continue hormone therapy after balancing the risks of ongoing HT with quality of life issues on an individual basis.
- Combined oral oestrogen plus progestin therapy is not recommended to prevent disease.
- This study tells us nothing about the use of oestrogen plus progestin for women who undergo early menopause (before the age of 40). It is generally recommended that such women use HT until they approach the average age of menopause and then at that time re-evaluate their need for ongoing treatment in the light of their personal risk.
- It is important that all women using HT should be reviewed at least annually by their prescribing health practitioner. Risks and benefits, and other alternatives can be discussed at this time for that individual woman.
The Women’s Health Secrets concurs that new information from this Lancet study reconfirms that the use of hormone therapy after menopause should primarily be for symptomatic relief.
The Women’s Health Secrets is committed to undertaking research in this area and to keeping up to date with new research findings and communicating these findings to women and their families.
The Women’s Health Secrets’s aim is to assist women to become well informed so they can be active participants with their health practitioners, in decision-making about issues that affect their health and wellbeing.
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