November 20, 2008

Study Identifies Causes of Bone Loss in Breast Cancer Patients

Cancer Drugs Aren't the only Culprits

MAYWOOD -- Osteoporosis is a growing concern among breast cancer survivors and their doctors, because certain cancer drugs can cause bone loss.

But a new study has found that cancer drugs aren't the only culprits. Among 64 breast cancer patients referred to a bone health clinic, 78 percent had at least one other cause of bone loss, including vitamin D deficiency, excessive calcium excretion in urine and an overactive parathyroid gland.

"Doctors evaluating breast cancer patients for possible bone loss should look further than cancer drugs," said Dr. Pauline Camacho, lead author of the study in the Journal of Clinical Oncology. Camacho is an associate professor in the department of medicine, division of endocrinology and metabolism, Loyola University Chicago Stritch School of Medicine.

A co-author of the study, Dr. Kathy Albain, said breast cancer survivors "are just like the normal population as they age in that bone loss can be due to many treatable causes." Albain is a professor in the Department of Medicine, division of hematology/oncology at Stritch.

Previous studies have found that chemotherapy drugs can cause bone loss. Studies also have found that a class of breast cancer drugs called aromatase inhibitors can decrease bone mineral density and increase the risk of fractures in postmenopausal women. Aromatase inhibitors decrease the body's production of estrogen. While estrogen feeds cancer, it also protects against osteoporosis. Aromatase inhibitors include letrozole (trade name, Femara), anastrazole (Arimidex) and exemestane (Aromasin).

Researchers reviewed charts of 238 consecutive postmenopausal patients who had osteoporosis or osteopenia and were referred to the Loyola's Osteoporosis and Metabolic Bone Disease Center from 2000 to 2006. (Osteopenia is lower than normal bone mineral density, but not low enough to be classified as osteoporosis.) The patients included 64 women with breast cancer referred from Loyola's Cardinal Bernardin Cancer Center and 174 patients without breast cancer referred from primary care physicians.

Thirty eight percent of the breast cancer patients had vitamin D deficiency, compared with 51 percent of the non breast cancer patients. Another cause of osteoporosis, excessive calcium excretion in urine, was found in 16 percent of cancer patients and 8 percent of noncancer patients. And in 5 percent of patients, the parathyroid gland was overactive, producing a hormone that causes bone to lose calcium.

Vitamin D deficiency can be treated with prescription doses of vitamin D supplements. Excessive calcium excretion can be treated with a "water pill" that's also used to treat high blood pressure, Camacho said. There are various treatments for parathyroid gland disorder, depending on its cause.

In certain breast cancer patients, bone loss from cancer drugs can be treated with osteoporosis drugs such as alendronate sodium (Fosamax) and ibandronate sodium (Boniva), Camacho said.

Albain refers all her breast cancer patients for a comprehensive bone health evaluation when osteopenia or osteoporosis is discovered. "Just prescribing a medication for osteoporosis may not be enough for many of our patients," Albain said. "They deserve a thorough workup."

Patient Rosaleen O'Connor, 71, of Elmhurst, Il., learned she had osteoporosis while being treated by Albain for breast cancer. Albain referred O'Connor to Camacho, who prescribed calcium supplements, prescription vitamin D and the osteoporosis drug Boniva. Three years after O'Connor was diagnosed, her Stage 3 cancer is in remission, and she has suffered no bone fractures.

Other authors of the study, all from Loyola, are Dr. Amit Dayal, Dr. Josefina Diaz, Dr. Fadi Nabhan, Dr. Monica Agarwal, Dr. John Norton and Dr. Patricia Robinson.

The study was presented as a poster in the 2007 meeting of the American Society of Bone and Mineral Research in Honolulu. It was supported by an investigator-initiated grant from Procter and Gamble.

 

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Based in the western suburbs of Chicago, Loyola University Health System is a quaternary care system with a 61-acre main medical center campus, the 36-acre Gottlieb Memorial Hospital campus and 22 primary and specialty care facilities in Cook, Will and DuPage counties. The medical center campus is conveniently located in Maywood, 13 miles west of the Chicago Loop and 8 miles east of Oak Brook, Ill. The heart of the medical center campus, Loyola University Hospital, is a 570-licensed bed facility. It houses a Level 1 Trauma Center, a Burn Center and the Ronald McDonald® Children's Hospital of Loyola University Medical Center. Also on campus are the Cardinal Bernardin Cancer Center, Loyola Outpatient Center, Center for Heart & Vascular Medicine and Loyola Oral Health Center as well as the LUC Stritch School of Medicine, the LUC Marcella Niehoff School of Nursing and the Loyola Center for Health & Fitness. Loyola's Gottlieb campus in Melrose Park includes the 250-bed community hospital, the Gottlieb Health & Fitness Center and the Marjorie G. Weinberg Cancer Care Center.

About Loyola Medicine and Trinity Health

Loyola Medicine, a member of Trinity Health, is a quaternary care system based in the western suburbs of Chicago that includes Loyola University Medical Center (LUMC), Gottlieb Memorial Hospital, MacNeal Hospital and convenient locations offering primary and specialty care services from 1,877 physicians throughout Cook, Will and DuPage counties. LUMC is a 547-licensed-bed hospital in Maywood that includes the William G. and Mary A. Ryan Center for Heart & Vascular Medicine, the Cardinal Bernardin Cancer Center, a Level 1 trauma center, Illinois's largest burn center, a certified comprehensive stroke center and a children’s hospital. Having delivered compassionate care for over 50 years, Loyola also trains the next generation of caregivers through its teaching affiliation with Loyola University Chicago’s Stritch School of Medicine and Marcella Niehoff School of Nursing. Gottlieb is a 247-licensed-bed community hospital in Melrose Park with 150 physician offices, an adult day care program, the Gottlieb Center for Fitness, the Loyola Center for Metabolic Surgery and Bariatric Care and the Loyola Cancer Care & Research at the Marjorie G. Weinberg Cancer Center at Melrose Park. MacNeal Hospital is a 374-bed teaching hospital in Berwyn with advanced inpatient and outpatient medical, surgical and psychiatric services, advanced diagnostics and treatments. MacNeal has a 12-bed acute rehabilitation unit, a 25-bed inpatient skilled nursing facility, and a 68-bed behavioral health program and community clinics. MacNeal has provided quality, patient-centered care to the near west suburbs since 1919.

Trinity Health is one of the largest multi-institutional Catholic healthcare systems in the nation, serving diverse communities that include more than 30 million people across 22 states. Trinity Health includes 92 hospitals, as well as 109 continuing care locations that include PACE programs, senior living facilities and home care and hospice services. Its continuing care programs provide nearly 2.5 million visits annually. Based in Livonia, Mich., and with annual operating revenues of $18.3 billion and assets of $26.2 billion, the organization returns $1.1 billion to its communities annually in the form of charity care and other community benefit programs. Trinity employs about 129,000 colleagues, including 7,800 employed physicians and clinicians. Committed to those who are poor and underserved in its communities, Trinity is known for its focus on the country's aging population. As a single, unified ministry, the organization is the innovator of Senior Emergency Departments, the largest not-for-profit provider of home health care services—ranked by number of visits—in the nation, as well as the nation’s leading provider of PACE (Program of All Inclusive Care for the Elderly) based on the number of available programs.