When breast cancer spreads to bones, relatively new protective drugs called bisphosphonates can reduce skeletal damage, says a new systematic review of previous studies. While the new treatment approach does not improve survival rates, it can minimize disabling fractures, spinal cord compression and pain.
The bone-protecting medications are already in common used among patients with osteoporosis and multiple myeloma, a cancer that affects bone marrow. The skeleton is the most common site for the spread of breast cancer, affecting more than half of women for whom the cancer spreads.
"Bisphosphonates should be part of standard therapy in women with advanced breast cancer and clinically evident bone metastases," recommends lead author Dr. Nick Pavlakis, an oncologist at the University of Sydney in Australia. The report emphasizes that bisphosphonate treatment should be added to conventional anti-cancer treatments such as chemotherapy and hormone therapy.
There is "strong evidence," adds Pavlakis, that bisphosphonate use can "reduce the likelihood of new skeletal events, the rate of events and possibly bone pain."
"Until recently, the management of symptomatic bone disease depended on analgesics, radiotherapy, endocrine therapy, and chemotherapy," says the review. "Despite these frequently effective treatments, progressive skeletal destruction often leads to ongoing symptoms and deterioration of quality of life." The review appears in the current issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic. The authors analyzed results from 21 randomized controlled trials that evaluated oral or intravenous bisphosphonates in addition to hormone therapy or chemotherapy. Fifteen studies comprised 5,187 women with advanced breast cancer and bone metastases.
All 12 studies that evaluated the rate of bone problems revealed reductions ranging from 14 to 48 percent with bisphosphonate treatment. The study treatment also led to significant lessening of bone pain in seven studies.
The remaining six studies focused on 1,973 women with breast cancer but without known bone metastases. In these groups, bisphosphonate treatment did not seem to affect the occurrence of new metastases or skeletal events.
Side effects of bisphosphonates were generally mild and infrequent. They included stomach upset and occasional fever.
Pavlakis says there are several questions related to bisphosphonate treatment that remain unanswered. "The key area open to research is the use of bisphosphonates in early breast cancer," he says.
"There is no evidence currently available to definitely confirm that one bisphosphonate is better than another, mainly because the appropriate studies have not been done," he adds.