Adjuvant bisphosphonate treatment significantly improves breast cancer survival and reduces bone recurrence in postmenopausal women with early breast cancer, according to the results of a study presented at the 2013 San Antonio Breast Cancer Symposium (SABCS).
Bisphosphonates are drugs that are used to treat osteoporosis and cancer-related bone complications, but some research has indicated that bisphosphonates may have their own anticancer effects as well.
Researchers performed a large meta-analysis of 36 randomized controlled trials that included a total of 22,982 women. The studies compared the adjuvant use of bisphosphonate to no bisphosphonate or placebo.
When researchers examined the results for all women, there was no significant difference in the 10-year rate of all breast cancer recurrences or distant recurrences, including recurrence in bone. However, when they looked at the data for 11,306 postmenopausal women, they found that women taking bisphosphonates had a highly significant reduction in distant recurrence—the rate of recurrence was 18.4 percent among postmenopausal women taking bisphosphonates compared to 21.9 percent in those not taking them. Bisphosphonates also appeared to reduce the rate of bone recurrence in postmenopausal women—the rate of bone recurrence among women taking bisphosphonates was 5.9 percent compared with 8.8 percent for the other women. There was no significant effect on non-bone recurrence.
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Notably, the rate of breast cancer mortality was 15.2 percent among women taking bisphosphonates compared with 18.3 percent among their counterparts. The rate of all-cause mortality was 21.5 percent in the bisphosphonate group compared with 23.8 percent in the other group.
The researchers concluded that adjuvant use of bisphosphonates reduced the risk of bone recurrence by 34 percent and the risk of breast cancer death by 17 percent in postmenopausal women with early breast cancer. In addition, adjuvant bisphosphonates led to an absolute reduction of 3.4% in all-cause mortality.
Coleman R, Gnant M, Paterson A, et al. Effects of bisphosphonate treatment on recurrence and cause-specific mortality in women with early breast cancer: a meta-analysis of individual patient data from randomised trials. Presented at: 2013 San Antonio Breast Cancer Symposium; December 10-14, 2013; San Antonio, TX. Abstract S4-07.