Secondary causes for low BMD common

Many postmenopausal breast cancer survivors may have secondary causes of low bone mineral density that are potentially treatable, according to research published online on June 22 in the Journal of Clinical Oncology.

G. Bruce Mann, PhD, of the Royal Women’s Hospital in Victoria, Australia, and colleagues analyzed data from 200 women--median age at diagnosis, 62 years-who’d been diagnosed with breast cancer within the previous 5 years. Subjects’ bone mineral density (BMD) was checked, and blood samples were tested for serum calcium, vitamin D, thyroid function, and parathyroid hormone.

The researchers found that roughly 47% of the women had osteopenia and 12.8% had osteoporosis. Many had insufficient (37%) or deficient (27%) vitamin D, and 21% had higher than normal parathyroid hormone concentrations. Six women had primary hyperparathyroidism (PHPT) and two had recent surgery for the condition, while 27 had secondary hyperparathyroidism from vitamin D deficiency and six had normocalcemic hyperparathyroidism. Of the patients with low BMD and hormone receptor-positive cancer, the authors note that 8% had recent or new PHPT.

“Secondary causes of osteoporosis should be sought and corrected, particularly in patients with hormone receptor-positive breast cancer and low BMD. Vitamin D should be measured and supplemented if low; repeat testing is appropriate to confirm adequate vitamin D replacement. Calcium levels should be checked, PHPT should be specifically sought if calcium levels are high, and PHPT should be treated appropriately,” the authors conclude.

Two co-authors reported financial associations with Novartis Pharmaceuticals.

Mann GB, Kang YC, Brand C, et al. Secondary causes of low bone mass in patients with breast cancer: A need for greater vigilance. J Clin Oncol. 2009 Jun 22 [Epub ahead of print]; doi: 10.1200/JCO.2008.20.2549.