Osteoporosis Drug May Have Adverse Effects on Breast Cancer Patients with Vitamin D Deficiency, UAMS Study Shows

By todd

LITTLE ROCK – A researcher at the University of Arkansas for Medical Sciences (UAMS) has determined that a drug commonly prescribed for osteoporosis and bone cancer may have an adverse effect on breast cancer patients with a previously undiagnosed vitamin D deficiency.


Laura Hutchins, M.D., director of the Division of Hematology/Oncology in UAMS’ Arkansas Cancer Research Center (ACRC), has concluded that bisphosphonate drugs often prescribed to slow bone loss or to treat patients with bone cancer may cause prolonged negative effects in patients with vitamin D deficiency. These effects can include low calcium levels in the blood known as hypocalcemia or overactivity of the gland that helps control the release of calcium into the blood known as hyperparathyroidism.


“This finding has previously been noted in the general population but has not been evaluated in breast cancer patients,” Hutchins said. Breast cancer patients are commonly prescribed high doses of bisphosphonate medications, which include Actonel, Boniva, Fosamax, Aredia and Zometa.


Hutchins’ study was presented at the 29th Annual San Antonio Breast Cancer Symposium in December 2006. Additional researchers associated with the study were Andrea Wang-Gilliam, M.D., Ph.D., fellow, and Dorothy Miles, Ph.D., research associate.


“We often prescribe bisphosphonate drugs to breast cancer patients whose cancer has spread to the bone,” Hutchins said. “What we have found is that there is a prevalence of vitamin D deficiency among people who don’t appear to be at high risk. If physicians fail to screen and regulate a patient’s vitamin D level, we may see additional complications with the use of bisphosphonates.”


Critical for bone health, vitamin D aids in the body’s absorption of calcium and is primarily synthesized through the skin during sun exposure. Multivitamins and many calcium supplements may not include the recommended daily dose of vitamin D.


People with decreased sun exposure, problems with their liver or kidneys, or those who do not take an oral vitamin may be at risk for vitamin D deficiency. Symptoms of extreme deficiency include osteomalacia, or soft bones. However, mild deficiency may cause only nonspecific symptoms such as muscle aches.


“We have found at UAMS that about 60 percent of breast cancer patients with known vitamin D levels had lower levels than anticipated,” Hutchins said. “Profound vitamin D deficiency can occur even in those who take a vitamin supplement. Physicians must be vigilant in testing patients’ vitamin D levels and in providing supplements to those with low levels.”


UAMS is the state’s only comprehensive academic health center, with five colleges, a graduate school, a medical center, six centers of excellence and a statewide network of regional centers. UAMS has about 2,430 students and 715 medical residents. It is one of the state’s largest public employers with about 9,400 employees, including nearly 1,000 physicians who provide medical care to patients at UAMS, Arkansas Children’s Hospital, the VA Medical Center and UAMS’ Area Health Education Centers throughout the state. UAMS and its affiliates have an economic impact in Arkansas of $5 billion a year. For more information, visit www.uams.edu.