HRT Back in the News

By contrast, the latest Medical Journal of Australia carries an article showing an association between the drop-off in HRT use (40% between 2001 and 2003, following the 2002 Women's Health Inititiative study which showed a small increased absolute risk, reported as a large one in relative risk terms) and a reduction in breast cancer incidence among Australia women aged 50 and older.  The incidence rates in this group were lower by 6.7% in 2003 compared to 2001 – equivalent to 600 fewer cases.

Director of NBOCC, Dr Helen Zorbas, commented that this was the first time there has been a downward trend after 20 years of steadily increasing rates.  She also noted that the drop-off in HRT usage rates could not be said to have directly caused the decrease in breast cancer incidence, and that here may be other factors involved..

"In real terms this means that for every 1000 women in their 50s taking HRT over five years, there will be an additional four women diagnosed with breast cancer", said Dr Zorbas.  "The increase in breast cancer risk appears to decrease back to the level of non HRT users within a few years of stopping the treatment. The study does not change the current advice for Australian women regarding the use of HRT or short-term relief of menopausal symptoms such as hot flushes.  Women should be aware that there are both benefits and risks associated with the use of HRT”.

(Editor's comment: This message also applies to women who have or have had breast cancer.  Looking back it's amazing that we ever believed there were drugs which had benefits and no risks!  Another question which springs to mind, and may be more important, is the link, if any, between premenopausal women taking the contraceptive pill (similar components to HRT) and breast cancer.  Have they reduced their use, and is there any correlation?)

Prof John Boyages, from the Westmead Breast Cancer Institute was invited by investigators from the National Cancer Institute in the USA to determine why breast cancer incidence has gone down in the USA, using their previously published mathematical techniques.  Initial results were presented at the ASCO Breast Meeting in San Francisco last year.

“The jury is still out, but our preliminary findings for the USA, using complex mathematical modelling shows that the reduced rates of HRT use may be responsible for some or all the reduction in the risk of breast cancer depending on which studies (the UK Million Women’s Survey or the US Women's Health Initiative) you use.  Its not that simple, and the MJA article doesn't prove cause and effect. Other factors which need to be considered is the effect of screening picking up high rates of DCIS and potentially finally having an impact on the total breast cancer incidence" said Prof John Boyages.  The BCI has produced with support from software engineers funded by Microsoft Australia to develop the world's first HRT calculator based on this complex mathematical modelling to work out an individual's risk of breast cancer. At a recent visit to the NCI, the section head responsible for on-line calculators at the NCI said "it's the best calculator I’ve ever seen" Version 1 of the calculator is available at www.seemyrisk.com and is available for 19 states or countries and takes into account current age, family history, mammographic screening and the use of HRT. 

Sally Crossing AMFounding Chair, Breast Cancer Action Group NSW

Article published in BCAG NSW Newsletter No 72, June 2008