Take breast cancer drug for 10 years'
AAP June 3, 2013, 10:46 pm
A new study says taking a breast cancer drug for 10 years instead of five will improve survival.
Death rates from the most common type of breast cancer can be slashed by taking a drug for 10 years rather than the recommended five, according to a new study.
Women with oestrogen receptor positive breast cancer who take tamoxifen for a decade rather than the usual five years halve their risk of dying from the disease, according to research presented at the American Society of Clinical Oncology conference.
The Cancer Research UK report, called the ATTom study, looked at nearly 7000 women with breast cancer who, after five years of taking tamoxifen, either continued taking the drug for another five years or stopped treatment.
Among women who took tamoxifen for 10 years, 25 per cent fewer had recurrences of breast cancer and 23 per cent fewer died, compared with women who took the drug for just five years.
Dr Daniel Rea, clinical lead researcher based at the University of Birmingham, said: "These results are important as they establish that giving tamoxifen for longer than the current standard of five years significantly cuts the risk of breast cancer returning.
"Doctors are now likely to recommend continuing tamoxifen for an extra five years and this will result in many fewer breast cancer recurrences and breast cancer deaths worldwide.
"Tamoxifen is cheap and widely available so this could have an immediate impact."
Around three quarters of breast cancers are oestrogen receptor positive and may benefit from hormone therapy.
The female sex hormone oestrogen encourages breast cancers to grow by activating oestrogen receptors. Tamoxifen acts by blocking these receptors, reducing the chance of breast cancer returning after surgery or developing in the other breast.
The researchers said women taking tamoxifen can experience side effects similar to menopausal symptoms, such as night sweats and hot flushes.
Rare but serious side effects of tamoxifen include increased risk of endometrial cancer - cancer of the lining of the uterus - blood clots, and stroke.
The study found no increase in the incidence of stroke after 10 years of taking tamoxifen, but that endometrial cancer risk was higher.
But researchers said that for every endometrial cancer death that occurred as a side effect of long-term tamoxifen treatment, there would be 30 deaths from breast cancer prevented.
Professor Richard Gray, based at the University of Oxford, who presented the research at the conference, said: "Five years of tamoxifen is already an excellent treatment but there have been concerns that giving it for longer might not produce extra benefits and could even be harmful.
"The ATTom study establishes that the benefits of taking tamoxifen for longer greatly outweigh the risks."
