Treatment of breast cancer with bone metastasis: bisphosphonate treatment — current and future

There are a variety of treatments for patients with bone metastases from breast cancer. These include bisphosphonates, antitumor endocrine and cytotoxic systemic therapies, radiotherapy to the metastatic site, radionucleotides, and conservative treatment (analgesics). The optimal combination treatment for bone metastases is not clear. Bisphosphonates are effective for reducing skeletal complications such as bone pain, pathological fracture, bone surgery, and hypercalcemia. Bisphosphonates are recommended as the gold standard therapy for breast cancer with bone metastases. Treatment guidelines tend to recommend starting a bisphosphonate at the time of diagnosis of bone metastases. Animal models have supported the prevention of bone metastasis by bisphosphonate therapy, but three major adjuvant clinical trials of the oral bisphosphonate clodronate have yielded conflicting results. However, our preliminary trial of an intravenous bisphosphonate, pamidronate, showed effective inhibition of bone metastases. The use of bisphosphonates, especially zoledronic acid, as adjuvant therapy is promising, but it is still investigational.     

Bisphosphonate treatment and radiotherapy in metastatic breast cancer

Patients with advanced breast cancer frequently develop metastasis to bone. Bone metastasis results in intractable pain and high risk of pathologic fractures due to osteolysis. The treatment of breast cancer patients with bone metastases requires a multidisciplinary approach. Radiotherapy is an established treatment for metastatic bone pain. It may be delivered either as a localized low dose treatment for localized bone pain or systemically for more widespread symptoms. Bisphosphonates have been shown to reduce morbidity and bone pain from bone metastases when given to patients with metastatic bone disease. In vivo studies indicate that early bisphosphonates administration in combination with radiotherapy improves remineralization and restabilization of osteolytic bone metastases in animal tumor models. This review focused on a brief discussion about biology of bone metastases, the effects of radiotherapy and bisphosphonate therapy, and possible mechanisms of combination therapy in metastatic breast cancer patients.     

Prevention of bone metastases from breast cancer by adjuvant bisphosphonate therapy

There is increasing evidence regarding the importance of osteoclast activation in the pathogenesis of bone metastases. Cancer cells produce osteoclast-activating factors which play an important role in the development of bone metastases. Bisphosphonates are drugs that inhibit bone turnover by decreasing bone resorption. In patients with bone metastases from breast cancer, the effectiveness of bisphosphonate is well established for reducing skeletal complications, such as bone pain, pathological fracture, bone surgery and hypercalcemia. Recent attention has focused on a possible preventive effect on bisphosphonates of bone metastases. Animal models have supported the prevention of bone metastasis by bishosphonate therapy, but three major adjuvant clinical trials of the oral bisphosphonate clodronate have yielded conflicting results. However, our preliminary trial of intravenous bisphosphonate with pamidronate showed effective inhibition of bone metastases. Use of bisphosphonates as adjuvant therapy is still investigational yet promising. Several more randomized trials are underway to further investigate adjuvant therapy with bisphosphonates.     

The present and future role of bisphosphonates in the management of patients with breast cancer

At least 25% of patients with breast cancer develop skeletal metastases, with bone the site of disease producing the greatest morbidity. It is apparent that the bisphosphonates present an important component of the treatment strategy. They are now the treatment of choice in tumour-induced hypercalcaemia, and they can reduce bone pain and skeletal complications such as pathological fractures. In addition, bisphosphonates are being increasingly evaluated in the prevention of bone metastases and to prevent and treat cancer therapy-induced osteoporosis. Ongoing research is aimed at trying to define the optimum route, dose, schedule and type of bisphosphonate.     

The role of bisphosphonates in breast cancer: The present and future role of bisphosphonates in the management of patients with breast cancer

At least 25% of patients with breast cancer develop skeletal metastases, with bone the site of disease producing the greatest morbidity. It is apparent that the bisphosphonates present an important component of the treatment strategy. They are now the treatment of choice in tumour-induced hypercalcaemia, and they can reduce bone pain and skeletal complications such as pathological fractures. In addition, bisphosphonates are being increasingly evaluated in the prevention of bone metastases and to prevent and treat cancer therapy-induced osteoporosis. Ongoing research is aimed at trying to define the optimum route, dose, schedule and type of bisphosphonate.     

Bisphosphonates in Breast Cancer: From Metastasis to Prevention

Bisphosphonate compounds have efficacy for the prevention and treatment of osteoporosis as they reduce the risk of fractures due to bone fragility by one third to one half. Likewise, bisphosphonates are important supportive therapies for the management of bone integrity in patients with bone metastases from breast cancer as, in this setting, they reduce the risk of skeletal-related events by one third. Bone is a common, and often the first, site of involvement from advanced breast cancer. It is thought that bisphosphonates may slow the progression of metastatic breast cancer by altering communication between tumor cells and the bone microenvironment. Although bisphosphonates have not been shown to alter overall survival in metastatic breast cancer, preclinical and clinical data suggest that bisphosphonate therapy may have a role as an anticancer strategy. Proposed general mechanisms to explain this putative antitumor activity include effects on the bone microenvironment, immune response modulation, inhibition of angiogenesis, inhibition of proliferation, and induction of apoptosis. The optimization of bisphosphonate use is being investigated. This article discusses the clinical and basic scientific data surrounding zoledronic acid, which is the most potent nitrogen-containing bisphosphonate used in patients with breast cancer.     

Risks and benefits of bisphosphonates

Bone is the most common site for metastasis in cancer and is of particular clinical importance in breast and prostate cancers due to the prevalence of these diseases. Bone metastases result in considerable morbidity and complex demands on health care resources, affecting quality of life and independence over years rather than months. The bisphosphonates have been shown to reduce skeletal morbidity in multiple myeloma as well as a wide range of solid tumours affecting bone by 30-50%. Quite appropriately, these agents are increasingly used alongside anticancer treatments to prevent skeletal complications and relieve bone pain. The use of bisphosphonates in early cancer is also increasingly important to prevent the adverse effects of cancer treatments on bone health. These include ovarian suppression and the use of aromatase inhibitors in breast cancer patients and androgen deprivation therapy in those with prostate cancer. Bisphosphonate strategies, similar to those used to treat postmenopausal osteoporosis, have suggested that bisphosphonates are a safe and effective treatment for the prevention of treatment-induced bone loss. When compared to other cancer therapies, the frequency and severity of adverse events related to bisphosphonate therapy are generally mild and infrequent; thus, the benefits of treatment with any bisphosphonate almost always outweigh the risks. However, renal dysfunction may occasionally occur and over recent years, a new entity, bisphosphonate-associated osteonecrosis of the jaw (ONJ), has been described. The incidence, clinical importance and prevention strategies to minimise the impact of this problem on patients requiring bisphosphonates is discussed.     

Too much, too little, too late to start again? Assessing the efficacy of bisphosphonates in patients with bone metastases from breast cancer

The diagnosis of bone metastases can be a devastating occurrence for any woman with breast cancer. In this setting, bone metastases can result in skeletal-related events (SREs) such as pathologic fracture, spinal cord compression, and hypercalcemia. Several trials have confirmed the ability of bisphosphonates to reduce or delay these skeletal complications, and they should now be considered standard care for these women. The analysis of SREs is the typical primary end point in bisphosphonate studies. While not undermining their importance, the definition of SREs does not include complications important to patients, such as pain and immobility. It is these symptoms that are most frequently reported by patients, and bone pain and quality of life (QoL) are often measured as secondary end points in these trials. Bone pain and QoL measures are not standardized and are difficult to compare among patient populations. We do not yet know the true efficacy of bisphosphonates as analgesics or how they impact QoL. This paper reviews the current efficacy measures used in recent bisphosphonate trials and discusses their benefits and limitations. It also explores the role of bone biomarkers and their potential use in monitoring treatment response.     

Management of Metastatic Bone Disease and Hypercalcemia of Malignancy

Thirty years of research have established bisphosphonates as the most effective agents for the inhibition of osteoclast-mediated bone resorption, and they play an important role in the management of malignant bone disease. Bisphosphonates have been systematically improved through chemical engineering, and the newest nitrogen-containing compounds, including zoledronic acid and ibandronate, are 1000-fold more potent than first-generation compounds. Consequently, they can be administered at low molar doses via short intravenous infusions without compromising renal safety. Bisphosphonates have a variety of metabolic effects on osteoclasts. Nitrogen-containing bisphosphonates inhibit protein prenylation via the mevalonate pathway, thereby inhibiting osteoclast activation and inducing apoptosis. Preclinical studies suggest that bisphosphonates also have direct and indirect antitumor activity. In animal models, bisphosphonates reduced skeletal tumor burden and bone metastases. Currently, intravenous bisphosphonates are the standard therapy for hypercalcemia of malignancy, and they have become an integral part of the treatment of bone metastases in conjunction with standard antineoplastic agents. Intravenous bisphosphonates quickly normalize serum calcium, reduce skeletal complications, and palliate bone pain in patients with bone metastases. Intravenous pamidronate (90mg via 2-hour infusion every 3–4 weeks) has, until recently, been the international standard for the treatment of osteolytic bone lesions from breast cancer or multiple myeloma. However, 4mg zoledronic acid (via 15-minute infusion) is quickly becoming the new standard based on evidence that it is as safe and effective as 90mg pamidronate in patients with breast cancer and multiple myeloma and significantly more effective for hypercalcemia of malignancy. Consequently, the American Society of Clinical Oncology guidelines for breast cancer and multiple myeloma recommend pamidronate or zoledronic acid for patients with radiographic evidence of osteolytic bone destruction. Moreover, 4mg zoledronic acid is the only bisphosphonate that has demonstrated significant clinical benefit in patients with other solid tumors, including lung cancer, and prostate cancer patients with primarily osteoblastic bone metastases. Bisphosphonates also may have activity in the adjuvant setting to prevent or delay the development of bone metastases. Studies with oral clodronate in early breast cancer have provided clinical evidence that bone metastases can be inhibited, and the studies are ongoing with more potent bisphosphonates. Bisphosphonates have also been shown to prevent cancer treatment-induced bone loss. These and other studies continue to redefine the role of bisphosphonates in the treatment of malignant bone disease and the management of bone health in cancer patients.     

Recommendations for zoledronic acid treatment of patients with bone metastases

The introduction of zoledronic acid, a new-generation bisphosphonate, has greatly extended the use of bisphosphonates in the treatment of patients with bone metastases. On the basis of results from three large, randomized, phase III clinical trials enrolling more than 3,000 patients, zoledronic acid (4 mg via 15-minute infusion) was approved in the United States for the treatment of patients with documented bone metastases from solid tumors in conjunction with standard antineoplastic therapy and patients with multiple myeloma. Zoledronic acid is also approved in Europe for the prevention of skeletal-related events in patients with advanced malignancies involving bone. Current treatment guidelines published by the American Society of Clinical Oncology recommend the use of intravenous bisphosphonates at first radiographic evidence of osteopenia in patients with multiple myeloma or osteolytic bone lesions in patients with breast cancer to significantly reduce the occurrence and delay the onset of skeletal complications. Zoledronic acid has also demonstrated efficacy in the treatment of bone metastases in patients with prostate cancer, lung cancer, and other solid tumors. Bisphosphonate therapy is generally well tolerated but can be associated with increases in serum creatinine. Therefore, monitoring renal function is required for all patients receiving bisphosphonate therapy. Serum creatinine should be monitored before each dose and treatment withheld until any serum creatinine elevations have resolved to baseline levels. Caution should be exercised when treating patients who are receiving other potentially nephrotoxic therapies. With these simple precautions, intravenous bisphosphonate therapy is safe for long-term use and provides durable treatment benefits.     

American Society of Clinical Oncology guideline on the role of bisphosphonates in breast cancer. American Society of Clinical Oncology Bisphosphonates Expert Panel.

PURPOSE: To determine clinical practice guidelines for the use of bisphosphonates in the prevention and treatment of bone metastases in breast cancer and their role relative to other therapies for this condition. METHODS: An expert multidisciplinary panel reviewed pertinent information from the published literature and meeting abstracts through May 1999. Additional data collected as part of randomized trials and submitted to the United States Food and Drug Administration were also reviewed, and investigators were contacted for more recent information. Values for levels of evidence and grade of recommendation were assigned by expert reviewers and approved by the panel. Expert consensus was used if there were insufficient published data. The panel addressed which patients to treat and when in their course of disease, specific drug delivery issues, duration of therapy, management of bony metastases with other therapies, and the public policy implications. The guideline underwent external review by selected physicians, members of the American Society of Clinical Oncology (ASCO) Health Services Research Committee, and the ASCO Board of Directors. RESULTS: Bisphosphonates have not had an impact on the most reliable cancer end point: overall survival. The benefits have been reductions in skeletal complications, ie, pathologic fractures, surgery for fracture or impending fracture, radiation, spinal cord compression, and hypercalcemia. Intravenous (IV) pamidronate 90 mg delivered over 1 to 2 hours every 3 to 4 weeks is recommended in patients with metastatic breast cancer who have imaging evidence of lytic destruction of bone and who are concurrently receiving systemic therapy with hormonal therapy or chemotherapy. For women with only an abnormal bone scan but without bony destruction by imaging studies or localized pain, there is insufficient evidence to suggest starting bisphosphonates. Starting bisphosphonates in patients without evidence of bony metastasis, even in the presence of other extraskeletal metastases, is not recommended. Studies of bisphosphonates in the adjuvant setting have yielded inconsistent results. Starting bisphosphonates in patients at any stage of their nonosseous disease, outside of clinical trials, despite a high risk for future bone metastasis, is currently not recommended. Oral bisphosphonates are one of several options which can be used for preservation of bone density in premenopausal patients with treatment-induced menopause. The panel suggests that, once initiated, IV bisphosphonates be continued until evidence of substantial decline in a patient's general performance status. The panel stresses that clinical judgment must guide what is a substantial decline. There is no evidence addressing the consequences of stopping bisphosphonates after one or more adverse skeletal events. Symptoms in the spine, pelvis, or femur require careful evaluation for spinal cord compression and pathologic fracture before bisphosphonate use and if symptoms recur, persist, or worsen during therapy. The panel recommends that current standards of care for cancer pain, analgesics and local radiation therapy, not be displaced by bisphosphonates. IV pamidronate is recommended in women with pain caused by osteolytic metastasis to relieve pain when used concurrently with systemic chemotherapy and/or hormonal therapy, since it was associated with a modest pain control benefit in controlled trials. CONCLUSION: Bisphosphonates provide a meaningful supportive but not life-prolonging benefit to many patients with bone metastases from cancer. Further research is warranted to identify clinical predictors of when to start and stop therapy, to integrate their use with other treatments for bone metastases, to identify their role in the adjuvant setting in preventing bone metastases, and to better determine their cost-benefit consequences.     

Bone metastases in breast cancer

Opinion statement Patients with advanced breast cancer who develop bone metastases suffer from longterm skeletal morbidity. Complications of bone metastases include pain, pathologic fractures, and spinal cord compression, which have a significant impact on the quality of life of patients. Treatment options for patients with bone metastases include surgery, radiation, and analgesics to reduce bone pain and to prevent or repair fractures. Intravenous bisphosphonates can delay the onset of bone metastasis and reduce the percentage of patients who experience skeletal complications of bone metastasis, thus reducing skeletal morbidity. For the past 6 years, pamidronate disodium (90 mg administered by 2-hour intravenous infusion) has been the treatment of choice for the prevention of skeletal complications of bone metastases in patients with breast cancer. However, a more potent bisphosphonate, zoledronic acid (4 mg administered by 15-minute intravenous infusion), was approved for use and has improved efficacy in patients with bone metastases. Because of the increased efficacy and more convenient infusion time, zoledronic acid may become the new standard of care for the treatment and prevention of skeletal complications secondary to bone metastases in patients with breast cancer. Phase III clinical trials have shown that patients with an existing skeletal complication are more likely to develop subsequent complications compared with patients who have not experienced a complication. Therefore, zoledronic acid therapy should be initiated when the patient is diagnosed with bone metastasis.     

Bisphosphonate therapy for bone metastases from Breast Cancer: Clinical results and a new therapeutic approach

BACKGROUND: We evaluated the usefulness of bisphosphonate (BIS) monotherapy, the safety of rapid infusion of BIS and the efficacy of BIS-sequential therapy for bone metastases from breast cancer. PATIENTS AND METHODS: Twenty-nine patients with bone metastasis or invasion were treated with BIS monotherapy. Each BIS (pamidronate 30 mg, alendronate 10 mg, or incadronate 10 mg) was infused over 30 minutes every two weeks a median of 12 times. RESULTS: With BIS therapy, five patients (17%) showed partial response of the bone lesions, and eighteen patients (64%) had pain relief. Of the nine patients treated with BIS-sequential therapy, one (11%) showed a partial response of the bone metastases, three (33%) had pain relief, and one (11%) showed a decrease in the serum tumor marker level. CONCLUSION: BIS therapy is effective against bone metastases from breast cancer, and rapid infusion of BIS is both safe and convenient for patients. BIS-sequential therapy can be a unique therapeutic option in some cases.     

Evolving role of bisphosphonates in women undergoing treatment for localized and advanced breast cancer

Breast cancer commonly metastasizes to bone, producing hypercalcemia, pathologic fractures, spinal compression, and pain that increase morbidity and affect the patient's mobility and quality of life. The use of bisphosphonates like pamidronate and zoledronic acid inhibits osteolytic activity caused by bone metastases. The use of bisphosphonates to prevent bone loss and preserve bone health in the adjuvant setting in women with breast cancer undergoing hormonal therapy with aromatase inhibitors or ovarian suppression is being actively investigated. Interestingly, clodronate, an oral bisphosphonate, has been shown in 2 trials to decrease the risk of recurrence in women with early-stage breast cancer, suggesting a direct or indirect antitumor effect of bisphosphonates. Trials to confirm the antitumor effects of bisphosphonates are currently ongoing. Prolonged intravenous bisphosphonate use has been associated with a rare risk of osteonecrosis of the jaw. Recommendations for management of this condition are discussed.     

Direct effects of bisphosphonates on breast cancer cells

In addition to inhibiting bone resorption, bisphosphonates have also been shown to exhibit antitumour effects. In vitro, bisphosphonates inhibit proliferation and induce apoptosis in cultured human breast cancer cells. In addition, bisphosphonate treatment interferes with breast cancer cell adhesion to bone matrix, and inhibits cell migration and invasion. The combination of bisphosphonates with other anticancer drugs such as the taxoids markedly enhances these effects. These newly recognized direct actions of bisphosphonates on breast cancer cells indicate that these agents may have a greater role to play in treatment of patients suffering from cancers with a propensity to metastasize to bone.     

Bisphosphonate as an adjuvant therapy for the pain of bone metastases, 3 cases

Pain from bone metastases limits mobility and may cause pathological fractures that can seriously impair the patient's quality of life. Conservative treatments such as orthopedic fixation, radiotherapy, and opioids sometimes fail to give satisfactory pain relief. Bisphosphonates have been reported to reduce the severity of pain from bone metastasis due to breast cancer, prostate cancer, and multiple myeloma. Recent clinical reports demonstrated the effectiveness of bisphosphonates in reducing pain from bone metastases in various malignancies. This study presents 3 cases of refractory pain from bone metastases due to thyroid, colorectal and hepatocellular carcinoma. Primary treatment included orthopedic fixation, radiotherapy, and/or parenteral opioids that failed to reduce bone pain. Bisphosphonate therapy was considered at the start of pain control treatment using opioids. All 3 cases showed gradual reduction in pain after i.v. pamidronate administration and allowed physicians to control further pain with opioids. In 1 case, the patient was successfully withdrawn from opioids. The role of bisphosphonates in painful bone metastases remains unclear. However, recent encouraging reports have indicated that bisphosphonate may become one of the adjuvant treatments available to control refractory bone pain from various malignancies.     

A case of effective bisphosphonate therapy for bone metastasis from breast cancer with multiorganic metastases

A 50-year-old woman with a past history of breast cancer was referred to our department of radiology for detailed examination after abnormal shadows on chest x-ray were detected following a routine medical examination. After lung biopsy via thoracotomy, segmental resection of the lung was performed and mediastinal lymph nodes were dissected. A histopathological diagnosis of breast cancer with lung metastasis and mediastinal lymph-node metastases was made. Later, the patient complained of pain in the left lower extremity. A diagnosis of a left tibial metastasis was made according to bone scintigraphy and MRI. Radiation therapy at 50 Gy was then initiated. Chemotherapy and hormone therapy combined with bisphosphonate therapy (Bisphonal, once in 2 weeks), was also begun. During the treatment, the patient had multiple organ metastases including multiple brain metastases, and metastases to submental lymph nodes and the left adrenal gland. However, her bone metastasis was limited to the left tibial bone and no other bone lesions were detected by bone scintigraphy and MRI. She did not experience adverse effects from the bisphosphonate therapy. We consider that the inhibition of extension and further metastases of the tibial bone metastasis noted in this patient reflected the efficacy of bisphosphonate therapy, and that bisphosphonate therapy might become an essential treatment in patients with bone metastasis of breast cancer.     

Treatment of metastatic bone disease in breast cancer: bisphosphonates

Like other metastases, bone metastases in breast cancer patients are not only a sign of the incurable nature of the underlying disease, but are also associated with specific complications. In particular, bone pain and pathological fractures impair the quality of life of those affected. Any treatment concept must, therefore, place the highest priority on preventing or reducing skeletal complications. There are two treatment options--local and systemic. Local therapy includes radiotherapy as well as surgical and orthopedic measures. The four pillars of systemic treatment are hormone therapy, chemotherapy, antiresorptive therapy with bisphosphonates, and treatment with centrally and/or peripherally acting analgesics. A precondition for successful treatment is close cooperation between medical/clinical oncologists, radiotherapists, surgeons/orthopedists, gynecologists, pain specialists, and endocrinologists (in the presence of a hypercalcemic syndrome). Patients with breast cancer associated solely with osseous metastasis may live for a number of years. It is, therefore, all the more important to start appropriate therapeutic measures early. Bisphosphonates play a particularly valuable role, since their main effect lies in the prevention of skeletal complications. Rather than replacing antineoplastic therapy, this class of substances supplements other treatments. Once started, bisphosphonate therapy should be given for the remainder of the patient's life, even in the event of osseous progression.     

Bisphosphonates and bone metastases]

Bisphosphonates, potent inhibitors of bone resorption have been emerging as the standard treatment of tumor-induced hypercalcemia during the 90's. All uncontrolled phase II studies up to 1992 had demonstrated efficacy in reducing morbidity in terms of bone pain, fracture and hypercalcemia. Other studies on intravenous bisphosphonates, with no other anti-tumor treatment, even demonstrated sclerosis of osteolytic breast cancer bone metastases. Randomised phase III studies only began after 1992. In multiple myeloma, one study with oral clodronate has reported a decrease in bone events and two other studies, one with intravenous pamidronate and the other with oral clodronate have both reported a decrease in skeletal events and bone pain. In breast cancer patients with bone metastases, five large studies have been reported: three with intravenous pamidronate, one with oral pamidronate and one with oral clodronate. All these studies have demonstrated the superiority of bisphosphonates over placebo on both bone pain and bone events, but have failed to show an increase in duration of survival. Bisphosphonates should therefore be considered as an important part of the palliative treatment in breast cancer patients with bone metastases. On the other hand, no definite conclusion can be drawn on the role of bisphosphonates in the treatment of prostatic carcinoma bone metastases yet. However, bisphosphonates should be considered as part of the standard therapy in managing painful lesions in patients with multiple myeloma, breast cancer and prostatic cancer. Nevertheless, further studies are needed with bisphosphonates in the adjuvant setting before bone metastases appear. Could new and more potent bisphosphonates such as zoledronate further reduce bone metastases morbidity?     

Bisphosphonates for metastatic bone disease: a therapeutic rationale

Metastatic bone disease is a common clinical occurrence in patients with advanced malignancy. Bisphosphonates target the underlying pathophysiology of skeletal metastases by inhibiting the activity of osteoclasts reducing bone turnover. By effectively reducing skeletal complications and improving patient quality of life, mobility and functioning, bisphosphonates have become a standard of care in this indication. Currently, most patients with metastatic bone disease are managed with intravenous (i.v.) bisphosphonates infused every 3–4 weeks. This requires regular hospital treatment and close patient monitoring for renal adverse events. Although daily oral bisphosphonate therapy is available as an alternative to i.v. dosing, its clinical utility is compromised by unpleasant gastrointestinal side effects and dosing inconvenience. The third-generation bisphosphonate ibandronate has been formulated as an i.v. and an oral therapy for the management of metastatic bone disease. Clinical trial data demonstrated that ibandronate reduces the risk of skeletal complications, relieves bone pain, improves quality of life and is well tolerated in patients with bone metastases from breast cancer. The availability of ibandronate will widen bisphosphonate treatment options for metastatic bone disease.