Drug prolongs lives of patients with hormone-sensitive breast cancer

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Hormone-blocking drugs such as tamoxifen are often given to patients who have undergone breast cancer surgery in order to target any cancer cells that may have been missed and prevent the disease from returning.

The researchers collected the findings from 20 clinical trials involving patients with early breast cancer taking tamoxifen every day for five years, and compared them with breast cancer patients who were not prescribed the drug.

Researchers found that women with hormone-sensitive breast cancer, also known as oestrogen-receptor (ER) positive breast cancer, had a lower chance of dying from the disease for at least 10 years after beginning the treatment.

The research, published online in The Lancet, shows the risk of dying from breast cancer was reduced by about a third over the 15 years after treatment began.

Around eight out of 10 women on tamoxifen took the drugs as directed by their doctor, suggesting that following the full course of treatment as strictly as possible for the full five years will give the best chance of reducing breast cancer deaths.

Christina Davies, a lead EBCTCG investigator, said: “Breast cancer is a nasty disease because it can come back years later. This study now shows that tamoxifen produces really long-term protection. For ER-positive disease, tamoxifen reduces 15-year breast cancer mortality by at least a third, whether or not chemotherapy has been given. Tamoxifen was developed 50 years ago and is long out of patent, but even if costs are ignored it remains a major first-line treatment option, especially for women whose ovaries are still functioning.”

Professor Jack Cuzick, a Cancer Research UK epidemiologist based at Queen Mary, University of London, said: "This research provides further evidence that taking tamoxifen for five years increases the chance of surviving breast cancer, with the benefits lasting long after women have finished their course of treatment.”

He also commented that tamoxifen is considered one of the most important drugs in the history of breast cancer treatment, and that a new generation of breast cancer drugs called aromatase inhibitors could be even more effective at preventing breast cancer in post-menopausal women, whose ovaries no longer produce oestrogen.

Reference

1. Early Breast Cancer Trialists' Collaborative Group (EBCTCG) (2011). Relevance of breast cancer hormone receptors and other factors to the efficacy of adjuvant tamoxifen: patient-level meta-analysis of randomised trials The Lancet DOI: 10.1016/S0140-6736(11)60993-8

klíčová slova: oestrogen receptor positive breast cancer, tamoxifen, survival