Bisphosphonates in Breast Cancer Patients with Skeletal Metastases

Osteopenia and osteoporosis in women with breast cancer

Osteopenia and osteoporosis are prevalent in women. Epidemiologic studies show that the risk of breast cancer is greater in postmenopausal women with higher bone mineral density (BMD). Standard treatments for breast cancer such as adjuvant chemotherapy or hormonal therapy can increase bone loss, and hence may increase the risk of osteoporosis. Premenopausal women treated with standard adjuvant chemotherapy frequently develop permanent ovarian failure, or early menopause. Ovarian failure is associated with accelerated bone loss, and bisphosphonates may mitigate this bone loss in women treated with adjuvant chemotherapy. Tamoxifen preserves BMD in postmenopausal women; however, in premenopausal women tamoxifen may increase bone loss. Anastrazole, an aromatase inhibitor, is approved for adjuvant treatment of postmenopausal women with early-stage, estrogen receptor-positive breast cancer. With a follow-up duration of less than 5 years, anastrazole-treated women experience increased fractures relative to those treated with tamoxifen. The management of osteopenia and osteoporosis in women with breast cancer generally does not differ from women without breast cancer. Adequate dietary calcium and vitamin D intake, encouraging weight-bearing exercise, and counseling about the relationship between smoking and alcohol and bone loss are all prudent recommendations for overall health and may lessen bone loss and the risk of subsequent osteoporosis. BMD should be measured in women with chemotherapy-induced ovarian failure, and in those on aromatase inhibitors. Bisphosphonates reduce the bone loss associated with chemotherapy-induced ovarian failure, and clinical trials evaluating third-generation bisphosphonates in women with chemotherapy-induced ovarian failure are underway. As many women with breast cancer will be long-term survivors, increasing recognition of maintaining skeletal health is important.

Nursing management of the patient with bone metastases

OBJECTIVES

To review the problem of bone metastases and strategies aimed at the management of bone metastases.

DATA SOURCES

Review articles, book chapters, research studies, and clinical practice.

CONCLUSIONS

As patients survive for longer periods, effective management of bone metastases becomes critical to maintaining or improving quality of life. Controlling pain, preventing fractures and oncologic emergencies, and promoting mobility and function are the outcomes of successful management.

IMPLICATIONS FOR NURSING PRACTICE

Use of a clinical algorithm may assist the nurse in identifying bone metastases and managing the clinical sequelae, such as pain.

The role of bisphosphonates in the treatment of bone metastases--the U.S. experience

Frequent complications of bone metastases include pain, pathologic fracture, hypercalcemia and spinal cord compression. Lytic bone metastases result from excessive activation of osteoclasts by tumor-produced cytokines. Aredia (pamidronate) is a potent bisphosphonate that inhibits osteoclast activation. In two dose-seeking phase I trials in patients with breast cancer and prostate cancer, repeated intravenous infusion of Aredia was shown to be safe and effective in reducing bone resorption and pain. In a randomized phase III trial of 377 patients with multiple myeloma, Aredia was administered in a dosage of 90 mg i.v. every 4 weeks. Compared with placebo, treatment with Aredia was associated with a significant decrease in bone pain and in the incidence and time to development of all skeleton-related events. Data from two phase III breast cancer trials each involving 300 patients are now being analyzed. The newer bisphosphonates can safely be used together with standard anticancer therapy to provide effective palliation of symptoms caused by lytic bone metastases.