TRIP

Aromatase Inhibitor Linked to Bone Loss (CME/CE)

MedPageToday, 2012

Spine, hip, neck, and other sites showed significantly worse bone loss with the aromatase inhibitor as well, despite the calcium and vitamin D supplementation used in the trial, the group reported online in the Lancet Oncology .
The trial had shown a 65% relative reduction in annual incidence of invasive breast cancer without an increase in skeletal fractures, though underpowered for clinical bone events.
The possibility of osteoporosis and fracture should be part of the discussion about primary prevention, Cheung and colleagues recommended.
"Women considering exemestane for the primary prevention of breast cancer should weigh their individual risks and benefits," they wrote.
"For women taking exemestane, regular bone monitoring plus adequate calcium and vitamin D supplementation are important."
Loss of bone density and fractures are known risks of in breast cancer survivors taking the drugs to reduce recurrence risk, Jane A.
"In light of the potential for widespread use of exemestane in the prevention setting," she wrote, "one might not be too reassured."
The problem may actually be worse than previously thought, based on the MAP.3 volumetric bone mineral density results, she suggested.
Most prior studies relied on dual-energy x-ray absorptiometry (DEXA), which in MAP.3 indicated two- to threefold less decline than volumetric measurements.
"Although DEXA is the current clinical gold standard for skeletal assessment of fracture risk, it does not capture bone geometry, microarchitecture, or biomechanical properties, which also contribute to fracture risk," the researchers acknowledged.
Their bone substudy included 351 of the total 4,560 postmenopausal women at moderately high risk of breast cancer in the trial.