Osteoporosis risk high for breast cancer survivors

Postmenopausal women who have survived early breast cancer face a higher than average risk of Osteoporosis, according to a report by Canadian researchers.

"Women with breast cancer are at higher risk of Osteoporosis after their treatment than the general population," told Dr. John R. Mackey from University of Alberta, Edmonton. He explained that this is especially so if women received chemotherapy or were treated with drugs called aromatase inhibitors.

Mackey and Dr. Anil A. Joy reviewed medical trials looking at the bone health of postmenopausal breast cancer patients.

Two large trials that evaluated the use of tamoxifen for breast cancer prevention showed no significant differences in the incidence of fractures in the tamoxifen and placebo groups, they found. In fact, one of the trials hinted at a decrease in fracture risk with tamoxifen treatment.

The story was different with aromatase inhibitors, however. These drugs include Arimidex (anastrozole), Femara (letrozole), and (Aromasin) exemestane, which are used to suppress estrogen in women whose tumors are hormone driven. All these drugs have been associated with changes in bone mineral density.

Anastrozole treatment was associated with a 60 percent higher fracture risk than tamoxifen treatment, the investigators report in the International Journal of Cancer. Letrozole treatment conferred a higher risk of osteoporosis than placebo treatment, and exemestane accelerated the loss of bone mineral density in the hip.

"In general, all postmenopausal women should have a baseline DXA (dual-energy X-ray absorptiometry test)," Mackey said.

"However, those on tamoxifen probably don't need aggressive repeat DXAs unless their bone mineral density is markedly low and they require more than calcium, vitamin D, and exercise," he advised.

For breast cancer patients with known osteoporosis, "they should be on bisphosphonate therapy and repeat DXA every 2 years or so," Mackey concluded. Bisphosphonate drugs are bone-builders such as Fosamax.

SOURCE: International Journal of Cancer, May 10, 2005.