‘Breast cancer drug harms bones’

'Wonder Drug' Exemestane Causes 3-Fold Increase In Bone Decay: Study

New Delhi: Exemestane, a commonly-used drug taken by early breast cancer patients in India — as frequently as once a day for five years — has been found to cause significant bone loss, even when they are given adequate calcium and vitamin Dsupplements. 

    The drug has been found to worsen age-related decrease in bone mineral density (BMD) by about three times, increasing chances of fractures manifold. In a study published in the medical journal Lancet, researchers from Canada said the drug causes loss of cortical bone, that comprises 80% of the human skeleton. In the study, cortical thickness of women who took exemestane declined by almost 8% compared to a 1% decline in those who didn't. 
    This finding is important because most fractures (80%) in old age are the result of greater loss of cortical bone and account for most disability. "Exemestane worsens age-related decreases in BMD," said lead author Angela Cheung from the University Health Network, Toronto. 
    Dr Bhawna Sirohi, head of medical oncology at Artemis Cancer Centre, said exemestane is considered a "wonder drug" in India, and is used very commonly to treat early breast cancer in post-menopausal women and for those whose breast cancer has worsened. 
    Dr Sirohi said, "Exemestane works by decreasing the amount of oestrogen production. This can slow or stop the growth of some breast tumours that need estrogen to grow. Using exemestane is a standard treatment for post-menopausal women with early stage hormone-receptor-positive 
breast cancer." Almost 75% of breast cancer cases are hormone driven, she added. 
    "Women considering exemestane for the primary prevention of breast cancer should weigh their individual risks and benefits. For women taking exemestane, regular bone monitoring plus adequate calcium and vitamin D supplementation are important," the study's authors cautioned. 
    Dr Sirohi said, "Before starting a patient on this drug, we always conduct a BMD scan and give calcium—1 gram daily and vitamin D—once a week—with the drug."