Expert disagrees with new study linking menopausal hormone replacement therapy with increased breast cancer risk

A joint study by Cancer Council NSW and Australian National University has revealed that doing Hormone Replacement Therapy (HRT) to deal with menopause symptoms boosts the risk of developing breast cancer. The study that was published in the International Journal of Cancer says that HRT doubles the cancer risk in menopausal Australian women.

The study compared menopausal hormone therapy use in 1,236 women with recently diagnosed invasive breast cancer and 862 women without cancer. However, the finding has been questioned by Professor Susan Davis, director of the Women's Health Research Program at Monash University who found the study “fairly simplistic” with a “crude analysis.” She found the sample size too small and biased.

According to The Conversation, the study’s finding is fully consistent with international evidence. It shows that breast cancer risk increases the longer menopausal HRT is carried out. The risks are even greater with oestrogen-progestagen therapy than oestrogen-only therapy.

Oestrogen-only therapy users who have been on HRT for about five years have 20 percent increased risk of developing breast cancer whereas oestrogen-progestagen therapy users have 60 percent increased risk. For ten years, the numbers are 30 percent and 120 percent respectively.

As per ABC Online, the Director of cancer research at Cancer Council NSW, Professor Karen Canfell considers the finding to be significant and pointed out that such a large-scale research has been conducted for the first time in Australia. She said that about 12 percent of women in the age group of 40-65 use menopausal hormone replacement therapy and that means about 500,000 women.

“The good news is that in our study, as in international studies, what we found was that the risks are not elevated in women after they stop using menopausal hormone therapy,” said Prof. Canfell.

However, Prof. Davis is of the opinion that results vary significantly from larger studies and poor-quality research is capable of misinforming community and clinical practice.

“So the gold standard of research is a randomised control trial and we have that from the Women's Health Initiative, that involved 27,000 women. The study that we're discussing now involved 1,200 women who developed breast cancer and 800 control, so it's very small,” said Prof. Davis.

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