Two new studies published in The Lancet suggest that two different classes of drugs, aromatase inhibitors (AIs) and bisphosphonates, can reduce breast cancer deaths in postmenopausal women with early breast cancer. The drugs can be used together, which increases the survival benefits and reduces some side effects.
The first study, led by Professor Mitch Dowsett of the Royal Marsden and The Institute of Cancer Research, London, used data from 9 randomized trials involving 30,000 postmenopausal women. The authors found that 5 years of treatment with an AI reduced the likelihood of cancer recurring by 30 percent and the risk of dying from breast cancer by 15 percent throughout the decade after beginning treatment, compared to 5 years of standard endocrine therapy (tamoxifen). Compared to no endocrine treatment, taking AIs reduced the risk of dying from breast cancer by an estimated 40 percent in the decade after beginning treatment.
The second study on bisphosphonates used data from 26 randomized trials involving almost 20,000 women. A common site that breast cancers spread to is bone, and bisphosphonates, which are usually used to treat osteoporosis, alter the bone microenvironment which could make it more difficult for cancer cells to spread. The researchers found that 2-5 years of treatment with bisphosphonates reduces the risk of cancer recurrence in the bone by 28 percent in postmenopausal women and also reduces the risk of dying of breast cancer by 18 percent in the decade after diagnosis, compared to no bisphosphonate. Bisphosphonate treatment did not reduce the risk of new breast cancers developing in the opposite breast, however. The study was led by Professor Robert Coleman from the University of Sheffield, UK.
Professor Richard Gray of the University of Oxford, who was the lead statistician for both studies, said: These studies provide really good evidence that both of these inexpensive, generic drugs can help to reduce breast cancer mortality in postmenopausal women. About two-thirds of all women with breast cancer are postmenopausal with hormone-sensitive tumours, so could potentially benefit from both drugs. The drugs are complementary, because the main side effect of aromatase inhibitors is an increase in bone loss and fractures, while bisphosphonates reduce bone loss and fractures as well as improving survival.
ACSH s senior director of medicine and public health, Dr. Gilbert Ross, added this: The main problem with AIs is premature induction of menopause, making their use difficult in younger breast cancer patients. But all in all, these reports provide even more hope that the toll of breast cancer can be reduced even further, as more clinicians become familiar with this new indication for the osteoporosis drugs, bisphosphonates.