Therapeutic strategies for treating osteolytic bone metastases

The recent progress in oncologic management of patients with localized cancer or metastatic disease has permitted a significant improvement in life expectancy. Nevertheless, bone metastases and their consequent skeletal-related events (SREs) are still associated with unfavorable prognosis and greatly affect quality of life. Global management of these bone metastases includes traditional local approaches (surgery, radiotherapy, etc.) and systemic administration of chemotherapeutic agents. This review focuses on treatments specific for bone metastases and, in particular, on inhibitors of bone resorption that are effective for preventing and delaying the development of SREs.

Comparative efficacy of bisphosphonates in metastatic breast and prostate cancer and multiple myeloma: a mixed-treatment meta-analysis

PURPOSE

A mixed-treatment comparison (MTC) was undertaken to compare the efficacy of zoledronic acid, clodronate, pamidronate, and ibandronate (i.v. and oral) in patients with skeletal-related events (SRE) secondary to metastatic breast and prostate cancer and multiple myeloma.

EXPERIMENTAL DESIGN

Studies of bisphosphonates in the three malignancies were identified and SRE data were extracted. Outcomes from the MTC were expressed as the annual SRE rate and as the mean likelihood (probability) ratio for the rate of SREs during treatment with zoledronic acid compared with the other bisphosphonates.

RESULTS

A total of 17 studies were identified (7 breast, 3 prostate, and 7 multiple myeloma). Data were available for all bisphosphonates in breast cancer; no data were available for ibandronate (oral or i.v.) in prostate cancer or for oral ibandronate in multiple myeloma. The SRE rates in breast cancer were 1.60 for zoledronic acid, 1.67 for oral ibandronate (excess SRE rate, 4%), 1.70 for i.v. ibandronate (6%), 2.07 for pamidronate (29%), and 2.29 for clodronate (42%). In prostate cancer, the SRE rates were 0.83 for zoledronic acid, 1.11 for clodronate (35%), and 1.41 for pamidronate (71%). In multiple myeloma, the SRE rates were 1.43 for zoledronic acid, 1.64 for pamidronate (15%), 1.90 for clodronate (33%), and 2.49 for i.v. ibandronate (75%).

CONCLUSIONS

Zoledronic acid seems to be the most efficacious bisphosphonate for reducing the risk of SREs in patients with cancer of the breast or prostate and those with multiple myeloma.

International Myeloma Working Group recommendations for the treatment of multiple myeloma-related bone disease

PURPOSE

The aim of the International Myeloma Working Group was to develop practice recommendations for the management of multiple myeloma (MM) -related bone disease.

METHODOLOGY

An interdisciplinary panel of clinical experts on MM and myeloma bone disease developed recommendations based on published data through August 2012. Expert consensus was used to propose additional recommendations in situations where there were insufficient published data. Levels of evidence and grades of recommendations were assigned and approved by panel members.

RECOMMENDATIONS

Bisphosphonates (BPs) should be considered in all patients with MM receiving first-line antimyeloma therapy, regardless of presence of osteolytic bone lesions on conventional radiography. However, it is unknown if BPs offer any advantage in patients with no bone disease assessed by magnetic resonance imaging or positron emission tomography/computed tomography. Intravenous (IV) zoledronic acid (ZOL) or pamidronate (PAM) is recommended for preventing skeletal-related events in patients with MM. ZOL is preferred over oral clodronate in newly diagnosed patients with MM because of its potential antimyeloma effects and survival benefits. BPs should be administered every 3 to 4 weeks IV during initial therapy. ZOL or PAM should be continued in patients with active disease and should be resumed after disease relapse, if discontinued in patients achieving complete or very good partial response. BPs are well tolerated, but preventive strategies must be instituted to avoid renal toxicity or osteonecrosis of the jaw. Kyphoplasty should be considered for symptomatic vertebral compression fractures. Low-dose radiation therapy can be used for palliation of uncontrolled pain, impending pathologic fracture, or spinal cord compression. Orthopedic consultation should be sought for long-bone fractures, spinal cord compression, and vertebral column instability.

Adjuvant bisphosphonate therapy for breast cancer patients: Standard of care or future direction?

Bone is the most common site of metastatic spread in breast cancer patients. The use of bisphosphonates (BPs) in women with bone metastases from breast cancer has been shown to reduce the incidence, and delay the onset of, skeletal-related events. Indeed, BPs are now an established standard of care in treating patients with bone metastases. As with many new therapies, once efficacy in the metastatic setting is demonstrated, therapies are tested in the adjuvant setting. There are a number of trials that have tested the hypothesis that BP therapy in women with early breast cancer may not only reduce the development of skeletal metastases but also improve both disease-free and overall survival; recent randomized trials have demonstrated intriguing results regarding the possible anticancer effects of adjuvant BP therapy. Furthermore, interesting signals are filtering through from trials evaluating the role of BPs to prevent cancer-treatment induced bone loss. Many of these trials will be reported in the near future. In this article we review possible subgroups that may benefit from adjuvant treatment with BPs, and ongoing trials that may offer more definitive answers.

Management of bisphosphonate treatment in clinical practice

Bisphosphonates have become important tools for the treatment of bone lesions from various solid tumors or from multiple myeloma. Management of bone health in patients with malignant bone disease from breast cancer, prostate cancer, lung cancer, and multiple myeloma was discussed in clinical case workshops held during the ZENITH meeting (April 2007, Prague, Czech Republic). Physicians in attendance were generally in agreement that bisphosphonate therapy is recommended for treatment of bone metastases and that treatment should be sustained over the duration of disease progression. Consensus is still evolving regarding the optimal duration of therapy and the emerging role of bisphosphonates in the management of bone loss in the adjuvant setting. Bisphosphonates have proven efficacy in reducing and delaying skeletal-related events in patients with bone metastases, and play a key role in preserving patient functional independence and quality of life. Furthermore, bisphosphonate therapy is a cost-effective strategy in the care of patients with bone metastases compared with the cost of treatment for fractures and other skeletal complications. Finally, communication with patients is critical to increase awareness of the benefits of bisphosphonate therapy. Increased patient involvement with treatment decisions will likely encourage patient compliance and thereby maximize clinical benefit from bisphosphonate therapy.