Tamoxifen provides better protection against the return of breast cancer when taken for five years, a new study has shown.
The long-term Cancer Research UK-funded trial showed that the cancer was less likely to come back in women who took the drug for five years, compared to two years. The results were published in the Journal of Clinical Oncology.
As a result of the study, experts are urging breast cancer patients to complete their full prescription of tamoxifen.
Of the nearly 3,500 patients who took part in the study, 40% of the women who took tamoxifen for five years experienced a return of their cancer, compared to 46% among those who took it for two years.
This is the first large study to compare the long-term benefits of tamoxifen over a ten year follow-up period.
Senior author Dr Allan Hackshaw said: “Women diagnosed with early stage breast cancer who are prescribed tamoxifen are recommended to take the drug for five years, but we know that many stop after two or three. Worryingly our results suggest that by doing this, they could increase their risk of cancer coming back.”
Coincidentally, taking tamoxifen for five years was also found to reduce the risk of developing or dying from heart disease. In women aged 50-59 at diagnosis, 60% fewer died as a result of a heart condition.
Kate Law, Director of Clinical Research at Cancer Research UK, added: “It’s vital that doctors and nurses continue encouraging women to finish their course of tamoxifen and providing the necessary support to ensure any side-effects are effectively managed. We would urge anyone who experiences problems taking their medication to consult their doctor without delay.”