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.