RCOG and the hormone replacement therapy (HRT) debate

Recent media reports have presented conflicting stories about the safety of HRT, stemming from the varied interpretations of the different studies which have appeared in recent years.

A summary of the latest studies is below:

HRT and cardiovascular disease

The latest Women’s Health Initiative (WHI) has noted that younger women (50 -59) taking HRT over a period of 10 years have shown no increased risk of developing CVD (Rossouw et al, JAMA 2007; 297: 1465-77). This is in contrast to evidence from the previous WHI study which stated an opposite finding, linking the risk of developing CVD to commencing HRT given in the form of a combination of estrogens with medroxyprogesterone acetate.

The women's international study of long duration estrogen and progestin after menopause (WISDOM) found that women starting or restarting combined HRT have increased cardiovascular and thromboembolic risk when treatment begins many years after the menopause (Vickers et al, BMJ, July 2007, doi:10.1136/bmj.39266.425069.AD). The study looked at a small group of 5,692 women from UK, Australia and New Zealand and found a significant increase in the number of "major cardiovascular events", such as angina, heart attack or sudden heart death, and potentially dangerous blood clots in the group given HRT, compared with those given placebo pills. The study also found a decreased risk of osteoporotic fracture and no difference in the risk of stroke or cancers. The study recommends further research to gauge the long-term risks and benefits of starting HRT near the menopause. It must be noted that this study was stopped upon the publication of the first WHI study which revealed a link between CVD and heart disease.

HRT and breast cancer

Studies have shown an association between HRT made up of a combination of estrogens and progestins with breast cancer. These observations however, are related to certain types of HRT and certain types of breast cancer for women of a particular age group. The recorded risks are statistically small and appear to be linked with the duration of therapy (Ravdin et al, NEJM 2007; 356: 1670-4). A recent study found that postmenopausal women who take combined estrogen plus progestin HRT for at least 5 years are increasing their risk of breast cancer. Researchers also found that women can quickly reduce their risk of breast cancer by stopping HRT (Chlebowski et al., NEJM 2009; 360(6): 573-587). In considering these findings, women should be aware that only a small percentage of combined estrogen plus progestin users continue use for more than five years (Brett & Reuben, Obstet Gynecol 2003; 102:1240-9). The Society of Obstetricians and Gynaecologists of Canada has noted that risk factors for breast cancer, such as hormones, should be evaluated in light of equally important risk factors related to lifestyle (Reid et al, JOGC 2009; 31(1): S5-S8). Research suggests that 34% of breast cancers could be avoided by making lifestyle changes at the time of menopause (Sprague et al, Am J Epidemiol 2008; 168(4): 404-11).

HRT and ovarian cancer

The recent Million Women Study has revealed an increased incidence of developing ovarian cancer in women on HRT, compared to women who have never used HRT (Million Women Study Collaborators, Lancet 2007; 369:1703-10). However, these risks are statistically small. Researchers report that the risk of developing ovarian cancer returns to pre-use levels once users stop using HRT.

Current recommendation

The current advice in the UK is for women using HRT, in consultation with their gynaecologist, to use the lowest dose which gives symptom control, for the shortest period of time. Given the findings from new research, the risks associated with the use of HRT are low and duration of use may, if necessary, be extended, as the use of HRT for many women provides welcome relief from distressing postmenopausal symptoms (Grady & Barrett-Connor, BMJ 2007; 334:860-1).

Based on the current evidence, therefore, starting HRT at the early onset of the menopause, and carrying on for a few years apparently carries little risk in healthy women. Taking medication also confers some benefit to bone strength (Farquhar C et al, Cochrane Database Syst Rev. 2009 Apr 15;(2):CD004143) and a small reduction in the risk of colonic cancer (Johnson JR et al, Cancer Epidemiol Biomarkers Prev 2009;18(1):196-203). All women commencing HRT should be advised of type, dose, mode of delivery and duration, and doctors should tailor treatment to individual patients.

Next steps

The Royal College of Obstetricians and Gynaecologists (RCOG) is fully aware of the controversy over HRT and in 2006, to enable better understanding for professionals and patients, proposed to NICE that it should undertake an unbiased evidence-based guideline review on the management of the menopause.

It is hoped that this proposal will be accepted and that the guideline production will be overseen by a chairperson with open-minded views on the benefits and risks of HRT.

Update

The Medicines and Healthcare products Regulatory Agency (MHRA), has updated its safety advice on HRT in September 2007. To view this document and the advice, please visit www.mhra.gov.uk/mhra/drugsafetyupdate.

The Society of Obstetricians and Gynaecologists of Canada has challenged the popular notion that hormone therapy does more harm than good and has issued new clinical guidelines and updated research information about menopause and its management. The update suggests that many women experiencing troublesome symptoms have been scared away from HRT due to misunderstandings about risks. The authors stress that while menopause is a natural transition in a woman’s life, there is no “one size fits all approach” when it comes to menopause symptoms and treatments. To view these documents, please visit http://www.sogc.org/media/advisories-20090122_e.asp.

References

 Last updated on 26 May 2009

 

 

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