New Estimates of Breast Cancer Risks Associated With HRT Examined

In the United Kingdom, new estimates of the increased risks of breast cancer associated with the use of different hormone replacement therapy (HRT) preparations have been examined. The findings of the study are published by The BMJ.

Hormone replacement therapy is linked to higher risks of breast cancer for older women. For longer-term HRT use, the increased risks are lower than those reported.

‘Exposure to most HRT drugs is associated with an increased risk of breast cancer, and that the levels of risks vary between types of HRT, with higher risks for combined hormone treatments and for longer duration of use.’

Hormone replacement therapy is used to relieve menopausal symptoms such as hot flushes and night sweats. Treatments include tablets containing estrogen-only or a combination of estrogen and progestogen, as well as patches, gels, and creams.

A previous study reported higher than expected breast cancer risks associated with HRT, but there is still uncertainty around the risks associated with HRT's different types and durations.

So, the Universities of Nottingham and Oxford researchers assessed the differences in breast cancer risks linked to individual component hormones used in HRT.

Researchers used two UK primary care databases (QResearch and CPRD) linked to hospital records to compare HRT prescriptions for 98,611 women aged 50-79 who were diagnosed with breast cancer between 1998 and 2018 with those of 457,498 women of the same age and from the same general practice who didn't develop breast cancer.

The research team analyzed risks by HRT type by recent (1-5 years) and past (5 or more years) use, and by short term (less than 5 years) and long term (5 years or more) use.

Factors such as alcohol consumption, smoking, family history, and other prescribed drugs were taken into consideration.

34% of women with a breast cancer diagnosis and 31% of controls had used HRT recently or in the past.

Compared with never use, there was a 15% associated increased risk of developing breast cancer for estrogen-only therapy for recent long-term users. In comparison, there was a 79% associated higher risk for combined estrogen and progestogen therapy.

Past long-term use of estrogen-only therapy and past short-term estrogen-progestogen use was not linked with increased breast cancer risk.

"Our results add more evidence to the existing knowledge base and should help doctors and women to identify the most appropriate HRT formulation and treatment regimen, and provide more consistently derived information for women's health experts, healthcare researchers, and treatment policy professionals," they conclude.

Source: Medindia