Women pre-disposed to breast cancer should be offered Tamoxifen, says study

Research carried out by Queen Mary, University of London has revealed that tamoxifen and three other drugs can significantly reduce the occurrence of breast cancer in women at risk from the disease.

A study published in the leading medical journal Lancet shows that based on medical records of 83,000 women, drug treatment in tamoxifen, raloxifene, arzoxifene or lasofoxifene, collectively known as selective oestrogen receptor modulators (SERMs), reduced breast cancer incidence by 38% in those at risk.

All four drugs target the oestrogen receptor which is the part of the breast cancer cell that oestrogen attaches to, stimulating the cell to multiply. They lock on to these receptors in order to stop oestrogen promoting further cell growth.

Researchers conducted a medical experiment that examined the effectiveness of SERMs over a five year period before stopping the treatment and examining the results for a further five years. It was found that after five years of treatment, the risk of breast cancer fell by 42% and a further reduction of 25% was also seen in women five years after they had stopped taking the medication.

No difference was observed in the numbers of deaths resulting from breast cancer, however the study found that these drugs significantly increased the risk of blood clots and caused side effects like vein thrombosis. The medication also led to a reduction in the risk of fractures, except tamoxifen, the use of which showed an increase in endometrial womb cancers and a decrease in diagnoses after women ceased taking it.

Tamoxifen is widely used by women over a five year period as part of their post-surgery treatment for oestrogen receptor positive (ER positive) breast cancer, while the other three drugs are used to treat osteoporosis.

Whilst the new study suggests the benefits of using these drugs as a preventative tool, tamoxifen is currently not approved as preventive medication for the disease in the UK. In January 2013, the National Institute for Health and Care Excellence (NICE) issued a draft stating that tamoxifen should be recommended for women at high risk of breast cancer. The finalised guidelines are expected to be announced later this year.

Aastha Gill