For the first time, researchers believe they may be able to predict which breast cancer patients are at high risk of developing bone metastases. By identifying these patients, researchers say drugs now used to treat bone cancer may also prove useful in preventing the development of such metastases in susceptible patients. Researchers are calling for studies to see if these drugsbisphosphonates in addition to antineoplastic treatmentscan help prevent the complication.
"It’s crucial to study further the effects of bisphosphonates in this group of patients, in order to offer them every advantage," said study leader Marco Colleoni, MD, of the European Institute of Oncology in Milan, Italy. "Treatments to prevent bone metastases may have a major impact on the course of breast cancer." Patients with known bone metastases are often treated with bisphosphonates, and randomized trials have demonstrated significant benefit in this group of women.
Two Distinct Groups at Highest Risk
Many patients develop bone metastases, but to date, physicians have not been able to predict which patients are at high risk. To help define the characteristics of patients most at risk, a worldwide group of researchers contributed data on 6,792 breast cancer patients. The data were then analyzed by the International Breast Cancer Study Group.
Overall, 27% of the patients in the study developed bone metastasis. However, the incidence was much higher in two large and distinct groups. In a group of 2,163 patients in whom cancer was found in four or more lymph nodes at the time of diagnosis, over 40% had developed bone metastases in the 10 years following initial treatment of their breast cancer.
In a group of 1,220 patients in whom cancer first reappeared after treatment in their lymph nodes, skin, or chest tissue, the risk of developing subsequent bone metastasis was four times higher than in the other patients. At 10 years following their initial diagnosis of cancer, bone metastasis was found in more than 36% of these patients, compared to 27% among all women enrolled in the study.