Randomized, placebo-controlled trial of clodronate in patients with primary operable breast cancer

Reduction in bone relapse and improved survival with oral clodronate for adjuvant treatment of operable breast cancer [ISRCTN83688026]

Introduction

Experimental and clinical data show that the oral bisphosphonate clodronate (Bonefos^®) can inhibit tumor-induced osteoclastic bone resorption. This randomized, double-blind, placebo-controlled, multicenter trial was designed to determine if the addition of oral clodronate to standard treatment for primary operable breast cancer could reduce the subsequent occurrence of bone metastases and thereby improve overall survival.

Methods

1,069 patients with primary operable stage I-III breast cancer were randomized to receive oral clodronate (1,600 mg/day) or placebo for 2 years, in conjunction with standard treatment for primary breast cancer including surgery, radiotherapy, adjuvant chemotherapy, and/or tamoxifen. All patients were assessed for bone metastases at two and five years and additionally when clinically indicated. Survival status was determined as of the close of the study on 30 June 2000 with a median follow up of 5.6 years. The treatment arms were compared using the unstratified log-rank test. Hazard ratios (HRs) with 95% confidence intervals were calculated.

Results

Oral clodronate significantly reduced the risk of bone metastases in all patients over the 5 year study period (51 patients versus 73 patients with placebo; HR = 0.692, P = 0.043); the difference was also statistically significant over the 2 year medication period (19 patients versus 35 patients with placebo; HR = 0.546, P = 0.031). These differences were most pronounced in patients with stage II/III disease (39 patients versus 64 patients with placebo, HR = 0.592, P = 0.009 over 5 years; 16 patients versus 32 patients with placebo, HR= 0.496, P = 0.020 over 2 years). Survival data also favoured the clodronate arm (HR for all patients = 0.768, P = 0.048; HR for stage II/III disease = 0.743, P = 0.041), although this was not significant due to multiple analyses. Oral clodronate was well tolerated, with mild-to-moderate diarrhoea being the most frequently reported adverse event.

Conclusion

These results confirm that oral clodronate will significantly improve the 5 year bone relapse free survival when used as a supplementary adjuvant treatment for patients receiving standard treatment for primary operable breast cancer.

Bisphosphonates for malignancy-related bone disease: current status, future developments

This review relates to the efficacy and safety of bisphosphonates in metastatic bone disease. It discusses practical recommendations and possible future indications for bisphosphonate therapy. The current aims of bisphosphonates for metastatic bone disease are to prevent skeletal-related events (SREs), reduce bone pain and improve quality of life. Phase III clinical trials of clodronate and pamidronate have established their efficacy against bone complications in patients with breast cancer and multiple myeloma, while randomized trials have shown SRE reductions with zoledronic acid in patients with breast cancer and multiple myeloma, prostate cancer, and lung and other solid tumors. These bisphosphonates also have some effect on metastatic bone pain. Ibandronate is a new aminobisphosphonate, available in more than 40 countries outside of the US as intravenous and oral formulations for the prevention of skeletal events in patients with breast cancer and bone metastases. Phase III studies have shown that both intravenously and orally administered ibandronate have efficacy for the prevention of skeletal events and for the reduction of metastatic bone pain. In addition to efficacy, the long-term tolerability of bisphosphonates in metastatic bone disease influences drug selection. Besides their use in patients with established bone metastases, recent and ongoing research suggests that bisphosphonates also have clinical benefit in the adjuvant setting, and for the treatment of cancer-treatment-induced bone loss. Such interesting new developments may underpin a new era of bisphosphonate use sometime in the near future.

[Hypercalcemia of malignancy: clinical features, diagnosis and treatment]

Hypercalcemia associated with malignancies is reported in up to 20 to 30% of patients with cancer during the course of the disease, and points to a poor prognosis. Symptoms related to the central nervous system, as progressive mental impairment, stupor and coma, predominate. Alterations in kidney function (water-concentrating defect leading to polyuria) and gastrointestinal tract (anorexia, nausea, vomiting) corroborate to dehydration and a further increase in serum calcium. Cancer-induced hypercalcemia may be classified as: 1) local osteolytic hypercalcemia (LOH), due to marked increase in osteoclastic bone resorption in areas surrounding the malignant cells within the marrow space; 2) humoral hypercalcemia of malignancy, caused by the secretion of parathyroid hormone-related protein (PTHrP) by the malignant tumor; 3) ectopic hyperparathyroidism; 4) 1,25(OH)2 D-secreting tumors. Adequate control of hypercalcemia is necessary to give the patient time to respond to anti-cancer therapy. Volume expansion with saline will correct dehydration, improve glomerular filtration and increase urinary calcium excretion, which may be further stimulated by loop diuretics. Intravenous bisphosphonates are the most effective agents to control hypercalcemia, as they block osteoclastic osteolysis and also have antitumoral effects, decreasing bone metastases. New approaches to control the skeletal manifestations of malignancies are anti-PTHrP and anti-RANKL antibodies, osteoprotegerin, and also proteasome inhibitors in the case of multiple myeloma.

Bisphosphonates as adjuvant therapy for breast cancer

Great strides have been made over the last 20 years in the treatment of breast cancer and despite an increasing incidence, the number of deaths has fallen sharply since the late 1980s. The advent of new therapies, including taxanes and aromatase inhibitors, and exciting results announced recently using trastuzumab in the adjuvant treatment of HER2-positive patients should decrease this even further. However, although most patients present with disease that appears to be localized to the breast, a significant proportion of women will eventually develop metastatic breast cancer. Therefore, the detection and treatment of micrometastatic disease represents perhaps the most important remaining challenge in breast cancer management, and is the focus of extensive ongoing research. Bone is the most frequent site of distant relapse, accounting for approximately 40% of all first recurrences. In addition to the well recognized release of bone cell-activating factors from the tumor, it is now appreciated that the release of bone-derived growth factors and cytokines from resorbing bone can attract cancer cells to the bone surface and facilitate their growth and proliferation. Bisphosphonates are potent inhibitors of bone osteolysis and the inhibition of bone resorption could therefore have an effect on the development and progression of metastatic bone disease. They could represent an adjuvant therapeutic strategy of potential importance. Clinical trial results with the early bisphosphonate, clodronate, have proved inconclusive. A large, randomized, controlled trial has recently completed accrual and should provide the definitive answer to the question of the role of clodronate in this setting. More potent second- and third-generation bisphosphonates have also shown enhanced antitumor effects in preclinical evaluation and further studies are required to determine whether this antitumor potential of bisphosphonates translates to the clinical setting. Adjuvant bisphosphonates are, therefore, currently only recommended in the research setting and clinical trials evaluating the adjuvant use of these newer compounds are currently recruiting or being established. This article will review in more detail the rationale for the adjuvant use of bisphosphonates, the results of early trials, the progress of the later trials and the potential future role of bisphosphonates in the adjuvant treatment of breast cancer. In addition, it is increasingly acknowledged that many cancer treatments have detrimental effects on bone and can increase the risk of fracture. The increasing use of aromatase inhibitors, in particular, will become a major cause of treatment-induced bone loss. This bone loss can be prevented with bisphosphonate treatment and this will also be discussed.

Pilot studies of the effect of zoledronic acid (Zometa) on tumor-derived cells ex vivo in the ATP-based tumor chemosensitivity assay

There is debate regarding the direct effect of bisphosphonates against visceral metastases from solid tumors, despite their proven efficacy against the skeletal complications of metastasis. The aim of this study was to determine whether zoledronic acid showed direct activity against five ovarian cell lines and tumor-derived cells, and whether addition of zoledronic acid to cytotoxic agents increased their cytotoxicity. In this study we used a standardized ATP-based tumor chemosensitivity assay (ATP-TCA) to measure the activity of alendronate, clodronate and zoledronic acid in five ovarian carcinoma cell lines and human solid tumors (breast, lung, ovarian, unknown primary carcinoma, and cutaneous and uveal melanoma) (n=34). We also tested the combination of zoledronic acid with paclitaxel and cisplatin in tumor-derived cells. All five cell lines exhibited greater sensitivity to bisphosphonates than the tumor-derived cells and in all five the IC50 for zoledronic acid was less than 4 muM. In the tumor-derived cells, zoledronic acid showed concentration-dependent inhibition with a median IC50 for all tumors tested of 17 muM and evidence of apoptosis (caspase activation). Simultaneous addition of zoledronic acid to cisplatin or paclitaxel showed no major increase in cytotoxicity. We conclude that the activity of bisphosphonates was greater in cell lines than in tumor-derived cells. However, the pattern of activity of bisphosphonates was the same in cell lines and tumor derived cells. This study suggests a direct, or possibly an indirect, effect of zoledronic acid and other nitrogen-containing bisphosphonates against neoplastic cells, but simultaneous addition with cisplatin or paclitaxel does not substantially increase the activity of the cytotoxic agent.

New paradigms for therapy for osteosarcoma

Osteosarcoma is a primary bone malignancy generally affecting the young, with 60% of cases occurring before the age of 25 years and the peak incidence at 15 years. Survival has improved over the past several decades, with non- metastatic disease having an approximately 70% chance of long-term survival. Unfortunately, patients with metastatic disease at diagnosis or those who have recurrent disease have a dismal prognosis, with approximately 20% surviving long term. In this review article we describe several new therapies in development for osteosarcoma. These include immune-based therapies, strategies to inhibit tumor growth, radiotherapy, and the introduction of new chemotherapies and targets.

Osteonecrosis of the jaws in patients with a history of receiving bisphosphonate therapy

BACKGROUND

Bisphosphonates, inhibitors of osteoclasts, have been shown to alleviate many of the devastating consequences associated with metastatic bone disease. However, recent reports have shown that bisphosphonates may cause osteonecrosis of the jaws. Since the publication of these initial reports, the authors have treated several patients with osteonecrosis of the jaws who had a history of receiving bisphosphonate therapy.

METHODS

The authors reviewed the medical records of patients who visited their clinic between September 2003 and December 2004 and who had osteonecrosis of the jaws and a history of having received bisphosphonate therapy but no irradiation to the head and neck.

RESULTS

Eleven patients (four female and seven male) with a mean age of 69 years were included in this report. They had received bisphosphonate therapy for a mean duration of 34 months. Radiographic data showed loss of bone density at sites of osteonecrosis, and histologic examination demonstrated necrosis of bone without evidence of metastases.

CONCLUSIONS AND CLINICAL IMPLICATIONS

Further research is required for better understanding of the role of bisphosphonates in the development of osteonecrosis of the jaws. Until more is known, the authors recommend that measures be taken to prevent osteonecrosis those at risk, including identifying patients with a history of having received bisphosphonate therapy before they undergo dental surgery. To help identify such patients, the authors propose the use of a screening questionnaire. When feasible, physicians should consult with their patients' general dentists or oral surgeons before patients begin bisphosphonate therapy.

Ibandronate: efficacy in the treatment of metastatic bone disease

Ibandronate is a bisphosphonate treatment for metastatic bone disease. In Phase III trials in breast cancer patients, intravenous and oral formulations of ibandronate lowered the incidence of skeletal-related events, reduced metastatic bone pain scores throughout 2 years of treatment, and had significant positive effects on patient quality of life, demonstrating its efficacy in this condition. Recent pilot studies in other primary cancers suggest that a loading dose of ibandronate may relieve severe or opioid-resistant metastatic bone pain. In safety analyses, ibandronate was well tolerated with a safety profile comparable to placebo. Ibandronate therefore represents a treatment choice with documented efficacy and safety in metastatic bone disease from breast cancer.

Bisphosphonate Treatment Recommendations for Oncologists

Renal safety is an important consideration for oncologists who are treating patients with bisphosphonates. In recent years, there has been increasing awareness about the development of bisphosphonate-induced nephrotoxicity. This has emerged mainly from increased clinical experience with zoledronic acid (Zometa); Novartis Pharmaceuticals Corporation, East Hanover, NJ, http://www.pharma.us.novartis.com). For this reason, the U.S. and European product labels for i.v. zoledronic acid were recently updated to include additional renal safety cautions, including dose adjustment in patients with mild-to-moderate renal impairment. However, renal toxicity is not a class effect. The product label for ibandronate (Bondronat), F. Hoffmann-La Roche Ltd., Basel, Switzerland, http://www.roche.com) has remained unchanged since the launch of the drug in the European Union in 2003. Ibandronate does not require mandatory monitoring of kidney function prior to each infusion. In addition, ibandronate can be used in patients with varying degrees of renal impairment. It also can be used without restrictions for nephrotoxic medications, and dose adjustment is only required in patients with severe renal impairment. Clinical implications of the renal safety of ibandronate include reducing the physician and nursing time needed for managing the adverse renal events associated with bisphosphonate therapy and dosing based on renal function. There also are no added renal safety risks and fewer inconvenient hospital visits with ibandronate therapy. In addition to i.v. ibandronate, an oral formulation of the drug is available. Oral ibandronate therapy is especially desirable because the medication is convenient (with a small, once-daily tablet that can be taken at home), reducing the health care costs associated with infusions. Clinical studies also indicate that 50 mg oral ibandronate has an efficacy similar to that of i.v. bisphosphonates and is associated with a low incidence of adverse gastrointestinal events.

Efficacy of Ibandronate in Metastatic Bone Disease: Review of Clinical Data

Metastatic bone disease affects many cancer patients and has a significant disease burden because of complications such as pathologic fractures and severe pain, which affect patient mobility and quality of life. Bisphosphonates are the current standard of care for treating metastatic bone disease. Available agents have shown varying degrees of efficacy in clinical trials, and treatment potential can be limited by efficacy, tolerance, or toxicity issues. Ibandronate (Bondronat); F. Hoffman-La Roche Ltd., Basel, Switzerland, http://www.roche.com) is a highly potent, single-nitrogen bisphosphonate that is available in i.v. and oral formulations. In phase III trials in breast cancer patients, both formulations reduced the incidence of skeletal complications associated with metastatic bone disease and had significant and sustained effects on bone pain and patient quality of life. Open-label studies of loading-dose ibandronate administered over consecutive days suggest it also may be useful for relieving severe or opioid-resistant metastatic bone pain. New trials have been designed or are in progress that may extend the clinical indications of ibandronate for patients with metastatic bone disease.

N-(4-Hydroxyphenyl)retinamide and nitric oxide pro-drugs exhibit apoptotic and anti-invasive effects against bone metastatic breast cancer cells

Breast cancer most frequently metastasizes to bone causing decreased quality of life and morbidity. Since current treatments are palliative, strategies to prevent bone metastases in breast cancer patients are required. There is substantial evidence indicating that high levels of nitric oxide (NO) suppress tumor growth and metastasis in vivo. We hypothesize that agents that produce high concentrations of NO could prevent the spread of breast cancer to bone. We previously demonstrated that the synthetic retinoid N-(4-hydroxyphenyl)retinamide (4-HPR) produces high levels of NO via the induction of NO synthases. NO pro-drugs are designed to produce large amounts of NO without inducing NO synthases but upon metabolism by their intracellular targets. The objective of this study was to determine the effectiveness of 4-HPR and an NO pro-drug, diethylamineNONOate/AM (NONO-AM), in inhibiting the growth and invasiveness of bone metastatic breast cancer cells. Parental MDA-MB-231 breast cancer cells were resistant to 4-HPR-induced apoptosis at clinically relevant doses, whereas 4-HPR-induced apoptosis in a dose-dependent manner in MDA-MB-231/F10 bone metastatic breast cancer cells. Unlike 4-HPR, NONO-AM induced apoptosis in a dose-dependent manner in both parental MDA-MB-231 cells and F10 cells. The bone metastatic F10 cells were more sensitive to the anti-invasive effects of 4-HPR and NONO-AM than were MDA-MB-231 cells. Although suppression of matrix metalloprotease-9 activity may be one mechanism by which 4-HPR decreases the invasion of F10 cells, it does not appear to be the anti-invasion mechanism of NONO-AM. These in vitro results suggest that 4-HPR and NO pro-drugs may be effective chemopreventive agents against bone metastatic breast cancer.

Therapeutic targets for antimetastatic therapy

Metastases are responsible for most cancer deaths. Despite dramatic advances in cancer therapy, the presence of metastases implies a significantly shortened survival and reduced quality of remaining life. Aside from prevention of cancer altogether, or significant improvements in early detection for most cancers, effective novel therapeutic strategies targeting metastasis should provide the greatest clinical benefit. Metastasis research has shown that many of the initial steps in metastasis are completed with a high degree of efficiency and may have occurred by the time of clinical diagnosis. Therefore, targeting the later stages of metastasis may offer a more promising therapeutic approach for the development of antimetastatic therapies. Appropriate clinical strategies include targeting dormant solitary cells, active preangiogenic metastases, or vascularised metastases. Dormancy of solitary single cells, seen clinically and experimentally, may be an explanation for cancer recurrence. Eradication or inactivation of these dormant cells could provide large benefit for patients. However, little is known about what makes cancer cells dormant and, therefore, a greater knowledge of the mechanisms of dormancy is needed. This review discusses potential biological targets, as defined by the steps in the metastatic process, for antimetastatic therapies and provides examples of clinical strategies for preventing or treating successful metastasis.

Ibandronate in metastatic bone disease: a review of preclinical data

Bisphosphonates are widely used to prevent and treat skeletal complications of metastatic bone disease. There is increasing evidence that, besides inhibiting osteoclast activity and reducing bone resorption, bisphosphonates also have an anti-tumor effect. This paper reviews the preclinical data for ibandronate. Ibandronate increased the proportion of apoptotic tumor cells in vitro and in vivo, possibly following activation of caspase-like proteases. In vitro, ibandronate also prevented adhesion and spreading of tumor cells to bone, and tumor cell invasion. These inhibitory effects were additive when ibandronate was given with paclitaxel or docetaxel. In animal models of tumor-induced osteolysis, ibandronate significantly reduced the development of osteolytic lesions. Efficacy for the prevention and reduction of bone metastases was related to the timing of treatment; ibandronate treatment initiated prior to or shortly after tumor cell inoculation inhibited the growth of bone metastases and preserved skeletal integrity most effectively. As with other bisphosphonates, the influence of ibandronate on soft tissue metastases has been inconsistent. Overall, preclinical evidence supports the rationale for adjuvant treatment with ibandronate for patients at risk of metastatic bone disease. The renal safety profile of ibandronate supports its suitability for long-term adjuvant use, even with intermittent high dosing. Adjuvant clinical trials have been initiated. The ability of bisphosphonates to preserve skeletal integrity is also of benefit in other clinical settings. Recent studies in rat models demonstrate improved osseointegration of joint implants following ibandronate therapy, with potential application in patients with conditions such as degenerative arthritis or osteoporosis.

Changes on Bone Mineral Density after Adjuvant Treatment in Women with Non-metastatic Breast Cancer

PURPOSE

. Adjuvant therapies have prolonged survival of non-metastatic breast cancer (NMBC) patients, but they also decrease bone mineral density (BMD). We have analyzed the effects of chemotherapy, hormone therapy with tamoxifen or both, on BMD of women with NMBC.

PATIENTS AND METHODS

We prospectively included 168 women with NMBC (stage I-III) referred to the Medical Oncology Service of University Hospital of Canary Islands between 1997 and 2001 (55 +/- 12 years; 37% premenopausal; 43 +/- 13 months of follow-up). We measured lumbar and hip BMD (g/cm2) at diagnosis, after chemotherapy and after 12 months of tamoxifen. If a low BMD was detected, women were treated with bisphosphonates.

RESULTS

BMD after chemotherapy (n = 83) significantly decreased at lumbar (1.014 +/- 0; 0.995 +/- 0, p = 0.0001), trochanter (0.701 +/- 0; 0.690 +/- 0, p = 0.001), intertrochanter (1.095 +/- 0; 1.078 +/- 0, p = 0.0001) and total hip (0.924 +/- 0; 0.915 +/- 0, p = 0.046) areas. Although 60% of the premenopausal women suffered amenorrhea after chemotherapy, there were not significant differences in BMD between them and women who retained menses. BMD of women who received 12 months of tamoxifen after chemotherapy increased--total hip (0.907 +/- 0; 0.922 +/- 0, p = 0.005) and intertrochanter (1.071 +/- 0; 1.091 +/- 0, p = 0.003)--or remained stable--lumbar, femoral neck, trochanter, and Ward's triangle (n = 39). When tamoxifen was the only adjuvant treatment, BMD after 12 months (n = 22) increased in trochanter area (0.644 +/- 0; 0.663 +/- 0, p = 0.011), and remained stable in all other sites. 50 (30%) patients were treated with bisphosphonates because of osteopenia.

CONCLUSION

Women with NMBC are affected by early bone loss after adjuvant chemotherapy. This bone loss is attenuated by one year of tamoxifen treatment.

Interference with the Microenvironmental Support Impairs the De novo Formation of Bone Metastases In vivo

Interference with the microenvironmental growth support is an attractive therapeutic strategy for repressing metastatic tumor growth. Bone is a highly dynamic tissue that is continuously remodeled by bone resorption and subsequent bone formation. Growth factors supporting bone metastatic growth are released especially during bone resorption. Differently from most other tissues, drugs that can limit local turnover, such as bisphosphonates, are available for bone. In the present study, we tested the hypothesis that inhibition of bone turnover can affect development and growth progression of experimental bone metastasis. Whole-body bioluminescent reporter imaging was used for the detection, monitoring, and quantification in vivo of the growth progression of bone metastases induced by intracardiac or intraosseous injection of luciferase-transfected breast cancer cells (MDA-231-B/luc+) to nude mice. Suppression of bone turnover by bisphosphonates, before bone colonization by cancer cells, inhibited by a great extent the number of developing bone metastasis. Tumor growth in the few, but still developing, bone metastases was affected only transiently. Reduction of bone turnover had no effect on growth progression of bone metastases, which were already established when bisphosphonate treatment was initiated, despite a substantial reduction in osteolysis. Therefore, cancer cells metastatic to bone, after an initial growth phase that depends on the interaction with the local stroma, become independent of microenvironmental growth factor support and progress autonomously. Inhibition of bone turnover may represent a useful adjuvant therapy especially for cancer patients at risk to develop bone metastasis.

Skeletal retention of bisphosphonate (pamidronate) and its relation to the rate of bone resorption in patients with breast cancer and bone metastases

Bisphosphonate pharmacokinetics may affect individual responses. Skeletal retention of pamidronate infused monthly to patients with bone metastases was highly variable (12-98%) and did not diminish with time, showing the capacity of the skeleton to retain large amounts of bisphosphonate. Relationships between skeletal retention of pamidronate and rate of bone resorption are complex and depend on previous treatment and the total amount of retained bisphosphonate.

INTRODUCTION

Bisphosphonates (BPs) given intravenously every 3-4 weeks are effective in the management of metastatic bone disease from breast cancer, but responses among patients vary, and it is not known whether current dose and dose intervals are appropriate for an individual patient. An influence of pharmacokinetics of BPs on antiresorptive action may contribute to this variation in response. To test this hypothesis, we determined the skeletal retention of intravenous pamidronate and its association to the rate of bone resorption in patients with bone metastases from breast cancer.

MATERIALS AND METHODS

In a cross-sectional study, 24-h urinary excretion of pamidronate and the biochemical marker of bone resorption N-terminal telopeptide of type 1 collagen and serum alkaline phosphatase were measured in 40 patients with bone metastases from breast cancer at the beginning, after 3-6 months, and after 1 year of treatment with intravenous pamidronate 90 mg every 3-4 weeks.

RESULTS AND CONCLUSIONS

Skeletal retention (dose--amount excreted into urine) 2 days after infusion varied between 12% and 98% (mean, 62%) of the administered dose, but there were no differences in retention between patients receiving pamidronate for the first time or after 3-6 months or after 1 year of treatment. Retention of pamidronate was related to the prevalent rate of bone turnover in previously untreated patients, whereas no such relationship was found in previously treated patients. Rate of bone resorption after treatment seemed to be related to the amount of pamidronate retained. During 1 year of treatment, retention of pamidronate remained constant, indicating no saturation of skeletal binding sites with treatment. The variability in retention among individual patients can be attributed to the number of available binding sites. This is related, however, to bone turnover only before the start of treatment. The apparent relationships between skeletal retention and antiresorptive effect could have implications for the design of optimal therapeutic regimens with BPs in patients with bone metastases from breast cancer.

HTLV-1 Tax transgenic mice develop spontaneous osteolytic bone metastases prevented by osteoclast inhibition

One in 20 carriers of human T-cell leukemia virus type 1 (HTLV-1) will develop adult T-cell leukemia/lymphoma (ATL), a disease frequently associated with hypercalcemia, bone destruction, and a fatal course refractory to current therapies. Overexpression of the HTLV-1-encoded Tax oncoprotein under the human granzyme B promoter causes large granular lymphocytic leukemia/lymphomas in mice. We found that Tax+ mice spontaneously developed hypercalcemia, high-frequency osteolytic bone metastases, and enhanced osteoclast activity. We evaluated Tax tumors for the production of osteoclast-activating factors. Purification of Tax+ tumor cells and nonmalignant tumor-infiltrating lymphocytes demonstrated that each of these populations expressed transcripts for distinct osteoclast-activating factors. We then evaluated the effect of osteoclast inhibition on tumor formation. Mice doubly transgenic for Tax and the osteoclast inhibitory factor, osteoprotegerin, were protected from osteolytic bone disease and developed fewer soft-tissue tumors. Likewise, osteoclast inhibition with bone-targeted zoledronic acid protected Tax+ mice from bone and soft-tissue tumors and prolonged survival. Tax+ mice represent the first animal model of high-penetrance spontaneous osteolytic bone metastasis and underscore the critical role of nonmalignant host cells recruited by tumor cells in the process of cancer progression and metastasis.

Three-year oral clodronate treatment does not impair mineralization of newly formed bone--a histomorphometric study

Bisphosphonates have been used successfully in the treatment of malignant hypercalcemia and skeletal metastases. Recently, clodronate has been studied in adjuvant settings in primary breast cancer. However, long-term effect of adjuvant clodronate on bone histology has not been reported, whereas bone mineral density studies have been published. The aim of this study was to examine the effect and safety of long-term clodronate treatment on bone quality as measured by histomorphometric techniques from bone biopsies. A total of 299 patients with early stage breast cancer were randomized to receive adjuvant oral clodronate (1.6 g/day) or to a control group for 3 years. All patients had adjuvant treatment: premenopausal women had six cycles of chemotherapy and postmenopausal women had antiestrogen for 3 years. Trabecular bone quality was examined in transiliac bone biopsy specimens by using histomorphometric techniques in 28 clodronate treated and 35 control patients who were disease-free at 3 years and who allowed the biopsy specimen to be obtained. No statistically significant differences were found in the values of osteoid, mineral apposition rate, or mineralization lag time in bone biopsies between the clodronate and the control groups. Postmenopausal women who received two antiresorptive drugs, antiestrogen and clodronate, developed features of secondary hyperparathyroidism with increased eroded surface and osteoclast number. In premenopausal, women clodronate with adjuvant chemotherapy, which induced early menopause and rapid bone loss in most of the patients, seemed to conduct slight depression in bone formation. Three-year oral clodronate treatment does not impair mineralization of newly formed bone: however, clodronate with different adjuvant breast cancer treatments has a diverse impact on bone histomorphometry depending on the type of therapy.

Bisphosphonates for breast cancer

BACKGROUND

Bone is the most common site of metastatic disease associated with breast cancer affecting more than half of women during the course of their disease. Bone metastases are a significant cause of morbidity due to pain, pathological fractures, hypercalcaemia and spinal cord compression, and contribute to mortality. Bisphosphonates, which inhibit osteoclast-mediated bone resorption, are standard care for tumour-associated hypercalcaemia, and have been shown to reduce bone pain, improve quality of life, and to delay skeletal events and reduce their number in patients with multiple myeloma. Several randomized controlled trials have evaluated the role of bisphosphonates in breast cancer.

OBJECTIVES

To assess the effect of bisphosphonates on skeletal events, bone pain, quality of life and survival in women with early and advanced breast cancer.

SEARCH STRATEGY

Randomized controlled trials were identified using the specialized register maintained by the Cochrane Breast Cancer Group (the search was applied to the databases Medline, Central/CCTR, Embase, CancerLit, and included handsearches from a number of other relevant sources). See: Cochrane Collaboration Collaborative Review Group in Breast Cancer search strategy.

SELECTION CRITERIA

Randomized controlled trials evaluating skeletal events in women with metastatic breast cancer and early breast cancer comparing: 1. treatment with a bisphosphonate with the same treatment without a bisphosphonate 2. treatment with one bisphosphonate with treatment with a different bisphosphonate.

DATA COLLECTION AND ANALYSIS

Studies were selected by two independent reviewers. Studies fulfilling the eligibility criteria were evaluated for quality, particularly concealment of allocation to randomized groups. Data were extracted from the published papers or abstracts independently by the two primary reviewers for each of the specified endpoints (skeletal events, bone pain, quality of life and survival). Data on skeletal events and survival were presented as numbers of events, risk ratios and ratios of event rates. Meta-analyses were based on the fixed-effects model (Mantel-Haenszel). Subjective qualitative ratings were used to summarize the quality of life and pain data.

MAIN RESULTS

Twenty one randomized studies were included. All studies in advanced breast cancer included women with clinically evident bone metastases (osteolytic and/or mixed osteolytic/osteoblastic) by plain xray and/or radionucleotide bone scans. In nine studies that included 2189 women with advanced breast cancer and existing bone metastases, bisphosphonates reduced the risk of developing a skeletal event by 17% (RR 0.83; 95% confidence interval (CI) 0.78-0.89; P < 0.00001). This effect was more modest, but still highly significant if episodes of hypercalcaemia were excluded (10 studies, 2656 women, RR 0.85; 95% CI 0.79-0.91 P = 0.0001). Overall, intravenous bisphosphonates reduce the risk of developing a skeletal event by 17 % (95% CI 0.78-0.89) compared with oral bisphosphonates, which reduce the risk of developing a skeletal event by 16 % (95% CI 0.76-0.93). Of the currently available bisphosphonates, 4 mg IV zolendronate reduces the risk of developing a skeletal event by 41% (RR 0.59, 95% CI 0.42-0.82), compared with 33 % by 90 mg IV pamdronate (RR 0.77, 95% CI 0.69-0.87), 18 % by 6 mg IV ibandronate (RR 0.82, 95% CI 0.67-1.00), 14 % by 50mg oral ibandronate (RR 0.86, 95% CI 0.73-1.02) and 16 % by 1600 mg oral clodronate (RR 0.84, 95% CI 0.72-0.98). Compared with placebo or no bisphosphonate, with bisphosphonates the skeletal event rate was lower in all of 12 studies in women with clinically evident bone metastases (median reduction of 29%, range 14-48%); statistically significant reductions were reported in 10 trials (four intravenous pamidronate, two oral clodronate, one intravenous ibandronate and two oral ibandronate, a single intravenous zolendronate study). Studies of intravenous zolendronate, pamidronate and oral clodronate in women with advanced breast cancer and clinically evident bone metastases showed significant delays in the median time to a skeletal event. Event-free survival was also reported to be longer in women receiving 6 mg of ibandronate compared with controls. Compared with placebo or no bisphosphonate, with bisphosphonates significant improvements in bone pain were reported in seven studies (90 mg iv pamidronate, 4 mg iv zolendronate, 6 mg iv ibandronate, 1600 mg oral clodronate and 50 mg oral ibandronate). Eight studies tested the effect of bisphosphonates compared with placebo on patient-rated quality of life using a referenced scale. Improvements in global quality of life were reported in only the three studies of iv and oral ibandronate. Treatment with bisphosphonates does not appear to affect survival in women with advanced breast cancer. Intravenous zolendronate (4 mg) appeared to be as effective as pamidronate (90mg) when directly compared in a single randomized double-blind study, based on the risk of developing a skeletal related event, the median time to first skeletal event and skeletal morbidity rate (events per year). Updated re-evaluation of the primary data in the overall population, by multiple event analysis using the method of Anderson-Gill, showed a reduction in the risk of developing any skeletal complication (including hypercalcamia) of 20 % (zolendronate 4 mg compared with pamidronate 90 mg, RR = 0.80, 95% CI 0.66 - 0.97, p = 0.025), suggesting a possible advantage of zolendronate 4 mg compared with pamidronate 90 mg. In the three studies of bisphosphonates in 320 women with advanced breast cancer without clinically evident bone metastases, there was no significant reduction in the incidence of skeletal events (RR 0.99; 95% CI 0.67-1.47; P = 0.97). In the three studies of oral clodronate that included 1653 women with early breast cancer, there was no statistically significant evidence of reduction in the risk of developing skeletal metastases (RR 0.82; 95% CI 0.66-1.01; P = 0.07), or of visceral metastases (RR 0.95; 95% CI 0.80-1.12, p = 0.53). However there was evidence of improved survival (RR 0.82; 95% CI 0.69-0.97, p = 0.02). However there was statistically significant heterogeneity among these studies and a random effects meta-analysis emphasizes the uncertainty of this finding (RR 0.75; 95% CI 0.45 - 1.25; p = 0.19). Toxicity or adverse events were described in 18 of the 21 studies. In general, few serious adverse events were reported. Toxicity associated with bisphosphonates is generally mild and infrequent. Renal toxicity is the main issue with intravenous zolendronate and is dose (8 mg) and infusion time related (< 15 minutes). With daily oral calcium (500 mg) and vitamin D (300-400IU) no significant renal impairment or hypocalcamia was observed with a 15 minute infusion of 4 mg IV zolendronate compared with 90 mg pamidronate. Monitoring of renal function with every cycle of zolendronate was undertaken in all studies and is recommended in practice. No significant renal toxicity was observed with intravenous pamidronate or ibandronate. Mild gastrointestinal toxicity is the main toxicity with oral clodronate and oral ibandronate.

AUTHORS' CONCLUSIONS

In women with advanced breast cancer and clinically evident bone metastases, the use of bisphosphonates (oral or intravenous) in addition to hormone therapy or chemotherapy, when compared with placebo or no bisphosphonates, reduces the risk of developing a skeletal event and the skeletal event rate, as well as increasing the time to skeletal event. Some bisphosphonates may also reduce bone pain in women with advanced breast cancer and clinically evident bone metastases and may improve global quality of life. The optimal timing of initiation of bisphosphonate therapy and duration of treatment is uncertain. In women with early breast cancer the effectiveness of bisphosphonates remains an open question for research.

Enhanced tumor regression and tissue repair when zoledronic acid is combined with ifosfamide in rat osteosarcoma

The efficacy of zoledronic acid (ZOL), with or without the anticancer drug ifosfamide (IFO), was tested on primary bone tumor growth using a rat-transplantable model of osteosarcoma. The effects on bone remodeling and tumor growth were analyzed by radiography, micro-computed tomography (micro-CT), and histological staining. The in vitro effects of ZOL were studied by proliferation, apoptosis, and cell cycle analyses on the osteosarcoma cells OSRGA compared to rat primary osteoblasts. Treatment with ZOL was effective in preventing the formation of osteolytic lesions that developed in bone sites and in reducing the local tumor growth, as compared to the untreated rats. The combination of ZOL and IFO was more effective than each agent alone in preventing tumor recurrence, improving tissue repair, and increasing bone formation as revealed by the analysis of trabecular architecture. In vitro studies demonstrated that ZOL was more potent against the OSRGA cell line than osteoblasts (with a half-maximal inhibitory effect on proliferation seen at 0.2 and 20 microM, respectively), the ZOL-induced inhibition of OSRGA proliferation being due to cell cycle arrest in S-phase. No effect on OSRGA apoptosis could be observed in vitro, as assessed by Hoechst staining and caspase-1 and -3 activation. In situ cell death was determined by TUNEL staining on tumor tissue sections. No significant difference in TUNEL-positive cells could be observed between ZOL-treated and -untreated rats. This is the first report of the anti-bone resorption and antitumoral activities of zoledronic acid in a rat model of osteosarcoma, and its beneficial association with an antitumoral chemotherapeutic drug in preventing tumor recurrence.

Bisphosphonates' use in metastatic

Bisphosphonates already have an established role in the management of the skeletal complications of metastatic bone disease. The development of new, highly potent compounds has led to investigation into their use as preventive agents in the adjuvant setting. The aim of the paper is to evaluate the evidence for their use in prevention and treatment.

Teletherapy and radiopharmaceutical therapy of painful bone metastases

Bone pain from metastatic disease is most common in cancers of the breast, prostate, and lung. Despite the World Health organization algorithm for treating such pain, the outcomes are not often satisfactory. In 2005, there will be 3 radiopharmaceuticals available in the United States that can reduce or relieve bone pain caused by osteoblastic metastases with apparently equal efficacy. Phosphorus-32 as sodium phosphate, strontium-89 ( 89Sr) as the chloride, and samarium-153 lexidronam may all be given intravenously (and 32P also orally) in patients where bone scintigraphy demonstrates a metastatic lesion causing the patient's bone pain. Side effects are usually mild and include pancytopenia with leukocyte and platelet nadirs at approximately 50% of baseline, and a mild-to-moderate, but brief, increase in pain ("flare") in approximately 10% of patients. At least 1 of these radiotracers, 89Sr, has the availability to reduce the incidence of new bone metastases as well, but, given alone, none prolong life. In a few studies in which 89Sr has been combined with chemotherapy, prolongation of patient survival has been demonstrated. Many questions remain as to the optimization of use of this group of radiopharmaceuticals, including whether combinations of radiopharmaceuticals with each other, with bisphosphonates or with chemotherapy can improve the therapeutic outcomes even more.

Management of bone metastases in cancer: a review

The presence of bone metastases is indicative of disseminated disease and typically indicates a short-term prognosis in cancer patients. Palliation of symptoms is the primary goal of therapy, with multidisciplinary efforts yielding the best results. New classes of drugs, such as bisphosphonates that significantly increase the time to first skeletal-related event (SRE), represent useful tools for the treatment of bone metastases. While the optimal duration of therapy needs to be defined, there is clinical benefit derived from the use of this class of agents. A potential role for bisphosphonates in the prevention of bone metastases is under current evaluation in clinical trials encompassing different solid tumor types. In combination with ongoing clinical trials, basic research to identify potential novel targets in the tumor cells-bone microenvironment will further define future strategies in the treatment of bone metastases.

Elderly Breast Cancer Patients: Adjuvant Chemotherapy and Adjuvant Endocrine Therapy

Older women have unfortunately been underrepresented in breast cancer clinical trials, with the majority of studies being restricted to patients younger than 70 years. Elderly patients are an inhomogeneous group and frequently suffer from comorbidities and/or impaired organ functions. These facts may often lead to death from causes other than cancer, thus nullifying any possible benefit of adjuvant treatment; furthermore, they render extrapolation of standard treatment recommendations to the elderly potentially hazardous, particularly with respect to chemotherapy. Specific clinical trials are therefore needed to investigate adjuvant treatments tailored for the heterogeneous older population.

Mechanisms of cancer metastasis to the bone

Some of the most common human cancers, including breast cancer, prostate cancer, and lung cancer, metastasize with avidity to bone. What is the basis for their preferential growth within the bone microenvironment? Bidirectional interactions between tumor cells and cells that make up bone result in a selective advantage for tumor growth and can lead to bone destruction or new bone matrix deposition. This review discusses our current understanding of the molecular components and mechanisms that are responsible for those interactions.

Approaches to managing bone metastases from breast cancer: The role of bisphosphonates

Conventional management of metastatic bone disease involves local and systemic therapies in various combinations, along with symptomatic management to provide optimal care. In recent years, it has become clear that adding bisphosphonates to these treatments reduces the incidence and severity of skeletal complications. Bisphosphonates can also relieve metastatic bone pain and improve quality of life, although the extent to which they have demonstrated these effects may differ between agents. While bisphosphonates are the standard of care for the treatment of bone metastases, clinical trials are investigating additional indications for these agents, including the use of intensive dosing regimens for the relief of severe or opioid-resistant metastatic bone pain and adjuvant treatment for the prevention of bone metastases and cancer treatment-induced bone loss. Current and future indications demand effective, well-tolerated and convenient bisphosphonates, and the benefits of different drugs must be balanced against their limitations. The cost-effectiveness of bisphosphonate treatment is also a consideration, given the high economic burden of metastatic bone disease from breast cancer.

Cost-effectiveness of oral ibandronate compared with intravenous (i.v.) zoledronic acid or i.v. generic pamidronate in breast cancer patients with metastatic bone disease undergoing i.v. chemotherapy

BACKGROUND

Ibandronate is the first third-generation bisphosphonate to have both oral and intravenous (i.v.) efficacy. An incremental cost-effectiveness model compared oral ibandronate with i.v. zoledronic acid and i.v. generic pamidronate in female breast cancer patients with metastatic bone disease, undergoing i.v. chemotherapy.

METHODS

A global economic model was adapted to the UK National Health Service (NHS), with primary outcomes of direct healthcare costs and quality-adjusted life years (QALYs). Efficacy, measured as relative risk reduction of skeletal-related events (SREs), was obtained from clinical trials. Resource use data for i.v. bisphosphonates and the cost of managing SREs were obtained from published studies. Hospital management and SRE treatment costs were taken from unit cost databases. Monthly drug acquisition costs were obtained from the British National Formulary. Utility scores were applied to time with/without an SRE to adjust survival for quality of life. Model design and inputs were validated through expert UK clinician review.

RESULTS

Total cost, including drug acquisition, was pound 386 less per patient with oral ibandronate vs. i.v. zoledronic acid and pound 224 less vs. i.v. generic pamidronate. Oral ibandronate gained 0.019 and 0.02 QALYs vs. i.v. zoledronic acid and i.v. pamidronate, respectively, making it the economically dominant option. At a threshold of pound 30,000 per QALY, oral ibandronate was cost-effective vs. zoledronic acid in 85% of simulations and vs. pamidronate in 79%.

CONCLUSIONS

Oral ibandronate is a cost-effective treatment for metastatic bone disease from breast cancer due to reduced SREs, bone pain, and cost savings from avoidance of resource use commonly associated with bisphosphonate infusions.

Review of ibandronate in the treatment of metastatic bone disease: experience from phase III trials

BACKGROUND

Metastatic bone disease is a serious clinical problem in patients with advanced cancer. Bisphosphonates inhibit the activity of osteoclasts and are the treatment of choice for bone metastases.

OBJECTIVE

This article reviews the efficacy and safety data from Phase III trials of ibandronate in metastatic bone disease.

METHODS

Phase III data (available as of June 2004) for ibandronate were reviewed. Literature searches using the MEDLINE database and abstracts from scientific meetings were used to obtain data from Phase III trials of ibandronate.

RESULTS

Compared with placebo, patients with bone metastases from breast cancer receiving IV ibandronate (6 mg infused over 1-2 hours every 3-4 weeks) or oral ibandronate (50 mg/d for up to 96 weeks) had a statistically significant reduction in skeletal complications, as measured by the Skeletal Morbidity Period Rate (P = 0.004 vs placebo). Multivariate Poisson regression analysis of the data showed that the risk of a new bone event was reduced by 40% with IV ibandronate 6 mg and by 38% with oral ibandronate 50 mg, compared with placebo (P < or = 0.003). Both formulations also reduced bone pain below baseline levels over 2 years (P < or = 0.001 vs placebo). IV and oral ibandronate were well tolerated, with adverse-event profiles comparable to placebo and no significant renal toxicity.

CONCLUSIONS

IV and oral ibandronate provide meaningful clinical benefits in patients with bone metastases from breast cancer. Both formulations reduce the risk of skeletal events and provide sustained relief from metastatic bone pain. With its favorable efficacy and safety profile, and the added convenience of the oral formulation, ibandronate provides improved treatment options for managing metastatic bone disease.

Should oral bisphosphonates be standard of care in women with early breast cancer?

There is increasing evidence that oral clodronate has important clinical benefits in early breast cancer. Longer-term follow-up data from two out of three randomized studies have shown that adjuvant clodronate improves survival. This article outlines the results of these studies and discusses the potential role for other bisphosphonates, such as ibandronate and zoledronic acid, in the adjuvant treatment of breast cancer.

Management of bone metastases in breast cancer

Patients with advanced breast cancer who develop bone metastases suffer an ongoing risk of skeletal complications that can have a significant impact on their quality of life (QoL). These complications include bone pain, pathologic fractures, spinal cord compression, and hypercalcemia of malignancy (HCM), a potentially life-threatening condition. Treatment options include radiotherapy to palliate bone pain and/or prevent impending fracture, orthopedic surgery to prevent or repair fractures, analgesics, and bisphosphonates, which can significantly reduce the risk of skeletal complications and delay their onset. Of the known bisphosphonates, zoledronic acid is the most potent. Since its regulatory approval in the United States and Europe in 2001, zoledronic acid (4 mg by 15-minute infusion) has become widely used and has replaced pamidronate (90 mg by 2-hour infusion) as the standard of care for treating bone metastases from breast cancer and bone lesions from multiple myeloma. Zoledronic acid has also demonstrated significant long-term benefits in randomized trials in prostate cancer and other solid tumors, whereas other bisphosphonates have failed. In long-term, phase III clinical testing, zoledronic acid provided significant treatment benefits beyond those of pamidronate in patients with breast cancer and demonstrated a safety profile comparable with pamidronate. Therefore, zoledronic acid is now recommended from the first diagnosis of bone metastasis. Other intravenous bisphosphonates include clodronate and ibandronate. Both are approved in Europe, but their efficacy relative to pamidronate and zoledronic acid is not known.

Clodronate : a review of its use in the prevention of bone metastases and the management of skeletal complications associated with bone metastases in patients with breast cancer

Clodronate (clodronate disodium, Bonefos) is a non-nitrogen-containing bisphosphonate that inhibits osteoclast activity, and thereby inhibits bone resorption. Clodronate has been extensively used in patients with advanced breast cancer, and is generally well tolerated. In patients with primary breast cancer, clodronate is currently the only bisphosphonate shown to improve survival rates and to reduce the incidence of bone metastases in randomised controlled trials. Further trials in patients with early breast cancer are warranted to confirm results to date and to determine the optimal duration of treatment, as well as the efficacy of the drug compared with other bisphosphonates. In the meantime, clodronate is a well established bisphosphonate which has shown beneficial effects in the prevention of bone metastases and on survival in patients with primary breast cancer.

Bisphosphonate therapy in the oncology setting

Patients with metastatic cancer and bone involvement are at chronic risk of skeletal complications, including bone pain, fractures, spinal cord compression and hypercalcaemia of malignancy. Therapies targeting the primary malignancy are often unable to prevent skeletal complications, which often require orthopaedic surgery, radiation therapy and analgesics. Intravenous bisphosphonates can reduce the risk of skeletal complications and the requirement for palliative radiation therapy. Since its broad regulatory approval, zoledronic acid (ZOMETA, Novartis Pharma AG/Novartis Pharmaceuticals Corporation) 4 mg by 15-minute intravenous infusion has become widely used to treat bone metastases from all solid tumours and is becoming the standard of care for advanced breast cancer and multiple myeloma. Additionally, cancer treatment-induced bone loss is an emerging problem in clinical oncology, and bisphosphonates -- particularly intravenous bisphosphonates -- may provide benefits even before bone lesions develop. Further investigations of bisphosphonates in these and other indications are ongoing.

Clodronate treatment influences MMP-2 associated outcome in node positive breast cancer

PURPOSE

Serum postoperative matrix metalloproteinase 2 (MMP-2) level is a predictor of outcome in node positive breast cancer and can be used to stratify patients into low and high risk groups. Our aim was to determine how clodronate treatment influences MMP-2 associated clinical outcome.

PATIENTS AND METHODS

Women with primary node-positive breast cancer were randomized to control group or to receive oral clodronate for 3 years. Adjuvant chemo- or endocrine therapy was given to all patients. The follow-up time for all patients was 5 years. MMP-2 and MMP-9 levels were quantitatively measured from the serum of 252 patients before and after 1 year clodronate treatment using enzyme-linked immunoassays.

RESULTS

In clodronate-treated patients, postoperative MMP-2 levels did not predict 5-year disease-free survival or overall survival (DFS, in low MMP-2 group (<5.32 ng/ml, median) 53% versus in high MMP-2 group (>median) 63%, p=NS; OS, 68% versus 63%, p=NS). When the patients were grouped according to serum MMP-2 levels, survival rates among patients with low MMP-levels were better in control than clodronate treated patients (DFS, 82% versus 53%, p = 0.003; OS, 91% versus 68%, p=0.014). Among patients with high serum MMP-2 levels, no significant difference in DFS or OS was found between control and clodronate groups. In multivariate analysis of low risk patients, independent predictors for DFS were treatment, age, nodal and PgR status, and those for OS treatment together with nodal and ER status. During 12 months follow-up, MMP-2 levels increased significantly more in clodonate receiving patients than in controls (p = 0.002). In comparison, when the patients were grouped according to MMP-9 levels, clodronate also impaired DFS among patients with low MMP-9 levels (82% versus 53%, p = 0.02), but no influence on OS was observed (83% versus 70%, p = 0.09).

CONCLUSIONS

Clodronate interferes with the prognostic value of serum MMP-2. Clodronate has a negative impact on outcome among patients with low serum MMP-2 and MMP-9 levels, while no such influence is observed among patients with high MMP-2 and MMP-9 levels.

Efficacy and safety of ibandronate in the treatment of neoplastic bone disease

Bone is an organ commonly involved in spreading neoplastic disease, especially in multiple myeloma and carcinoma of the breast, prostate and lung. Skeletal stabilisation and pain relief are the main treatment goals in metastatic bone disease. Bisphosphonate treatment inhibits osseous breakdown and is well-established as the current standard therapy for reducing complications of neoplastic bone disease (e.g., pain, fractures and hypercalcaemia). Ibandronate is a third-generation bisphosphonate that has recently been approved for the treatment of bone metastases caused by breast cancer. The oral and intravenous formulations of ibandronate appear to have comparable efficacy. Ibandronate has also been shown to provide significant and sustained relief from metastatic bone pain over 2 years of treatment, improving patient functioning and quality of life. With a favourable long-term safety profile and the added convenience and flexibility offered by its efficacious oral formulation, ibandronate represents a new therapeutic option for metastatic bone disease management.

Strategies to Prevent Chemotherapy-Induced Bone Loss in Women with Breast Cancer

Treatment-induced osteoporosis is an increasing problem for women diagnosed with breast cancer. As more women receive adjuvant endocrine therapy and chemotherapy, and breast cancer survival improves, the impact of cancer treatment on bone health and the morbidity associated with chemotherapy-induced bone loss becomes more of a significant medical concern. Endocrine agents like aromatase inhibitors and luteinizing hormone-releasing hormone agonists decrease the production of ovarian and adrenal estrogens and are widely used in the adjuvant and metastatic settings for treatment of women with hormone receptor-positive breast cancer. Estrogen is important for bone health. It stimulates osteoblasts and maintains bone integrity. As bone density decreases, the risk of fracture increases. This can include fractures of the wrist, femur, and vertebrae. Several potent bisphosphonates have been developed to prevent or treat cancer treatment-induced bone loss.

[Treatment of anemia and bone metastasis in metastatic non-small-cell lung cancer. A French survey]

Use of erythropoietin (EPO) for chemotherapy-induced anemia and biphosphonates (BP) for bone metastasis has increased steadily. However, there are no guidelines on their use in many situations such as non small cell lung carcinoma (NSCLC), which frequently alters quality of life markedly. Therefore, a multicentric survey was designed to assess the treatment of anemia and bone metastasis in chemotherapy-treated patients with non-small-cell lung carcinoma. Nine representative centers of the oncology working party of the French respiratory society (Groupe d'Oncologie de la Société de Pneumologie de Langue Française) participated. Inclusion criteria were stage IV NSCLC and at least one course of chemotherapy in the last 3 months. A total of 148 and 50 patients (pts) were included in the anemia and bone metastasis surveys, respectively. Anemia was present in 60.8% of patients, and was not treated in 75%; 15 patients received EPO (10.1%). Independent predictors of EPO use were presence of anemia-related symptoms, hemoglobin level, age and center: the rate of prescription in patients with anemia varied from 13 to 73% between centers. BP were administered in 38% of patients with bone metastasis. Independent predictors of BP use were calcium serum level, pain, and center with a rate of prescription ranging from 0 to 80% between centers. This study reveals that, in France, most patients with anemia are not treated, EPO being seldom prescribed. The use of both EPO and BP is highly variable between centers. Guidelines on the use of these supportive treatments could help improve the care for lung cancer patients receiving chemotherapy.

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.

Zoledronic acid inhibits visceral metastases in the 4T1/luc mouse breast cancer model

PURPOSE

It is established that bisphosphonates (BPs), specific inhibitors of osteoclasts, have beneficial effects on bone metastases of breast cancer. In addition, recent studies have reported that BPs have anticancer effects and suppress visceral metastases, too. However, the results of clinical studies are still conflicting. In the present study, we examined the effects of the BP zoledronic acid (ZOL), one of the most potent BPs currently available, on visceral metastases of breast cancer using an animal model in which mouse breast cancer cells 4T1/luc implanted at the orthotopic mammary fat pad spontaneously metastasize to multiple organs including bone, lung, and liver in female BALB/c mice.

EXPERIMENTAL DESIGN AND RESULTS

The 4T1/luc-bearing mice received single or four i.v. injections of ZOL (0.5 or 5 microg/mouse) during the whole experimental period. Bone metastases were reduced by the ZOL treatment. More importantly, ZOL significantly suppressed lung and liver metastases. Furthermore, ZOL prolonged overall survival of the tumor-bearing mice. Of interest, apoptosis in 4T1/luc cells colonized in bone was increased by ZOL; however, those in lung were not changed. In vitro studies demonstrated that ZOL inhibited cell migration and invasion and promoted apoptosis of 4T1/luc cells.

CONCLUSIONS

These results are consistent with the notion that ZOL affects breast cancer metastasis to visceral organs as well as bone. These effects of ZOL may be attributable to inhibition of migration and invasion of breast cancer cells. Clinical relevance of our experimental results needs to be determined in breast cancer patients with visceral metastases.

Skeletal health in postmenopausal survivors of early breast cancer

Estrogen plays an important role in the skeletal health of all women. Many therapies used in the treatment of breast cancer reduce estrogen levels and have the potential to affect bone negatively by increasing the risk of osteoporosis and associated bone fractures. The long-term effects of systemic endocrine therapy on bone, therefore, are an important consideration in the adjuvant setting. Tamoxifen has been shown to have a moderate protective effect on postmenopausal bone due to its partial estrogen agonist activity; however, its long-term use is potentially associated with negative side effects, such as an increased risk of thromboembolic disease and endometrial cancer. Newer agents, the third-generation aromatase inhibitors (AIs), anastrozole, letrozole and exemestane, for example, do not possess estrogen agonist effects and have improved breast cancer outcomes when compared to the standard 5 years of tamoxifen. However, patients treated with adjuvant AIs have been shown to have an increased incidence of osteoporosis and osteoporotic fractures. In order to select the optimal adjuvant therapy for each patient, it is important to assess the overall risk:benefit ratio for each endocrine strategy. All postmenopausal women should follow published guidelines to assess the risk of osteoporosis and, where appropriate, they should receive bone mineral density monitoring. Postmenopausal women with breast cancer who are at increased risk of osteoporotic fracture should be identified and managed with appropriate nonpharmacologic and pharmacologic measures.

Clinical management of osteoporosis in women with a history of breast carcinoma

Osteoporosis is a skeletal disorder that is characterized by low bone mass and compromised bone strength. Fractures are the clinically important consequence of osteoporosis and result not only in disability but also in excess mortality. Women who have a history of breast carcinoma may represent a unique population for whom screening and treatment for osteoporosis should be modified. A review of the English literature was performed that included original, review, consensus, and statement articles that were identified through Medline or National Institutes of Health-related links. According to the literature, osteoporosis constitutes a major public health problem. Approximately 55% of the U.S. population > or = 50 years of age has low bone mass (osteopenia or osteoporosis). Annually, > 200,000 women in the U.S. are diagnosed with breast carcinoma. Due to the high prevalence rates of both low bone mass and breast carcinoma in women, these two diseases commonly coexist in the same individuals. Women with a history of breast carcinoma may be at increased risk of developing bone loss and fragility fractures as a consequence of antineoplastic therapies. The majority of women treated for early-stage breast carcinoma do not develop recurrences, as a result of recent advances in therapy. Ensuring the diagnosis, prevention, and treatment of long-term toxicities and comorbid conditions like osteoporosis in breast carcinoma survivors is a serious concern and is of increasing importance. In this article, the authors address the evaluation and treatment of osteoporosis in women who have a history of early-stage breast carcinoma.

Steroid-free medium discloses oestrogenic effects of the bisphosphonate clodronate on breast cancer cells

Tamoxifen is the standard first-line endocrine therapy for breast cancer, but recent data indicate that it is likely to be replaced by the effective aromatase inhibitors (AIs), in both the metastatic and adjuvant settings. Aromatase inhibitors induce complete oestrogen deprivation that leads to clinically significant bone loss. Several ongoing or planned trials combine AIs with bisphosphonates, even more so that recent data reveal that clodronate may reduce the incidence of bone metastases and prolong survival in the adjuvant setting. Bisphosphonates can inhibit breast cancer cell growth in vitro, but they have never been studied in steroid-free medium (SFM), an in vitro environment that mimics the effects of AIs in vivo. Quite surprisingly, in SFM, clodronate stimulated MCF-7 cell growth in a time- and dose-dependent manner by up to two-fold (crystal violet staining assay), whereas it had no mitogenic activity in complete medium. The bisphosphonate similarly increased the proliferation of IBEP-2 cells, which also express a functional oestrogen receptor (ER), while it weakly inhibited the growth of the ER-negative MDA-MB-231 cells. Expectedly, 17beta-oestradiol stimulated the growth of MCF-7 and IBEP-2 cells cultured in SFM, and had no effect on MDA-MB-231 cells. Moreover, partial (4-OH-tamoxifen) and pure antioestrogens (fulvestrant, ICI 182,780), in combination with clodronate, completely suppressed the mitogenic effect of the bisphosphonate, suggesting that it was mediated by an activation of ER. In accordance with this view, clodronate induced ER downregulation, weakly increased progesterone receptor expression, and stimulated the transcription of an oestrogen-responsive reporter gene. In conclusion, we report a previously unknown stimulatory effect of clodronate on MCF-7 cells grown in SFM, in vitro conditions that are potentially relevant to the use of AIs for breast cancer. Moreover, our data suggest that ER is involved in these effects of clodronate on cancer cell growth.

The role of bisphosphonates in breast cancer

Patients with bone metastases from breast cancer are at high risk for debilitating skeletal complications. Bisphosphonates are effective inhibitors of tumour-induced bone resorption and significantly reduce the risk of skeletal complications in these patients. Several bisphosphonates have been investigated for the treatment of bone metastases in patients with breast cancer, including clodronate, pamidronate, ibandronate, and zoledronic acid. Among these agents, intravenous pamidronate and zoledronic acid have demonstrated the greatest clinical benefit based on conservative endpoints. Zoledronic acid is the only agent to be compared with another active bisphosphonate and has been shown to significantly reduce the risk of skeletal complications compared with pamidronate. On the basis of these results, zoledronic acid has rapidly become the new international standard of care for patients with bone metastases from breast cancer.

Perspectives on the future of bisphosphonate use in breast cancer patients

Bisphosphonates are effective for reducing the skeletal complications of metastatic breast cancer. Current treatment guidelines tend to recommend starting bisphosphonates at the time of diagnosis of bone metastases and continuing indefinitely or until the patients' performance status declines substantially. While meta-analyses of clinical trials have suggested that treatment should continue for at least 6 months to reduce skeletal-related events, few data exist on alternative strategies to optimize therapy. Other indications for bisphosphonates in the management of breast cancer include managing reduced bone mineral density in patients with early stage disease. In addition, because of considerable preclinical and clinical evidence that they may have direct antitumor actions, bisphosphonates are being tested as adjuvant therapy for early stage breast cancer in a number of large clinical trials.

Use of bisphosphonates can dramatically improve pain in advanced hormone-refractory prostate cancer patients

INTRODUCTION

Approximately 85% of patients who die from prostate cancer present the spread of bone metastases. Even though the radiological appearance of such metastases is osteoblastic, it is now known that these lesions coexist in their microenvironment with blastic and lytic lesions. The process always begins with bone lysis by osteoclast proliferation, paralleling nearby bone deposition. The treatment options are palliative and have poor clinical response with short-lived improvement. We have studied the clinical effect of bisphosphonates (clodronate) in the treatment of skeletal complications from prostate cancer.

MATERIALS AND METHODS

In an open prospective study, 58 patients with hormone-refractory prostate cancer with bone metastases were assessed from November 2000 to September 2003. The mean age was 70.3 y (range: 51-87 y). Bone scintigraphy, plain X-ray, assaying of prostate-specific antigen (PSA) and biochemical tests were requested before and following treatment. Patients were previously and subsequently assessed using the visual pain scale (0-10) and Karnofsky's index after the first and second intravenous (i.v.) infusions (administration of i.v. clodronate every 28 days) and every 4-6 months thereafter. Student's t-test was used for statistical analysis.

RESULTS

A total of 53 patients (91.4%) showed improvement after the first and/or second cycle, which persisted for at least 4 months (average 6.3 months). The averages on the visual pain scale improved from 7.4 (range: 2-8) to 2.4 (0-7) and on Karnofsky's index from 43 (32-58) to 73 (50-82). The radiological appearance of the metastases improved in 27 patients (46.5%) and there were few relapses (six patients; 10.3%).

CONCLUSIONS

Clodronate was effective in the treatment of skeletal complications from prostate cancer. There was an objective response in 91.4% of treated patients, with a marked improvement in the subjective visual pain scale evaluation as well as on Karnofsky's index, with low side effects.