Breast cancer treatment hard on the bones: study

By Martha Kerr, Reuters 19 September 2007

The bones of breast cancer patients tend to age prematurely as a result of chemotherapy and aromatase inhibitor therapy, according to research reported at the American Society for Bone and Mineral Research meeting this week.

The researchers advise that the bone health of these women be evaluated as if this were a much older population of women.

Dr. Pauline M. Camacho and colleagues at Loyola University in Chicago, Illinois, took a look back at the charts of 238 postmenopausal women referred to their institution between 2000-2005 for the management of osteoporosis or osteopenia -- a bone-thinning condition just short of osteoporosis.

Sixty-four women had a history of breast cancer, while 174 "control" women did not. The women with breast cancer had early-stage disease and were in the midst of, or considering, hormonal therapy with aromatase inhibitors.

Roughly three-quarters of the women in both groups had at least one secondary cause of osteoporosis, the researchers found. Vitamin D deficiency was the most common for both groups. The investigators found that 37.5 percent of the breast cancer group and in 51.1 percent of the non-breast cancer group were vitamin D-deficient.

"There is a high prevalence of secondary causes of osteoporosis among breast cancer patients undergoing or considering undergoing adjuvant hormonal therapy with aromatase inhibitors," Camacho told meeting attendees. "This prevalence was similar to the non-breast cancer group despite a difference in age."

"It is prudent" to measure bone mineral content before treatment, Camacho said, "and to screen patients with breast cancer for secondary causes of bone loss."

"These women should be evaluated as if they were much older," she added in an interview with Reuters Health. "It may be wise to keep them on tamoxifen, which is bone-sparing and avoid the aromatase inhibitors, which cause bone loss." Examples of aromatase inhibitors include anastrozole, sold as Arimidex, and exemestane sold as Aromasin.

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