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

Bone Health in Patients with Breast Cancer: Recommendations from an Evidence-Based Canadian Guideline

Bone loss is common in patients with breast cancer. Bone modifying agents (BMAs), such as bisphosphonates and denosumab, have been shown to reverse or stabilize bone loss and may be useful in the primary and metastatic settings. The purpose of this review is to provide clear evidence-based strategies for the management of bone loss and its symptoms in breast cancer. A systematic review of clinical trials and meta-analyses published between 1996 and 2012 was conducted of MEDLINE and EMBASE. Reference lists were hand-searched for additional publications. Recommendations were developed based on the best available evidence. Zoledronate, pamidronate, clodronate, and denosumab are recommended for metastatic breast cancer patients; however, no one agent can be recommended over another. Zoledronate or any oral bisphosphonate and denosumab should be considered in primary breast cancer patients who are postmenopausal on aromatase inhibitor therapy and have a high risk of fracture and/or a low bone mineral density and in premenopausal primary breast cancer patients who become amenorrheic after therapy. No one agent can be recommended over another. BMAs are not currently recommended as adjuvant therapy in primary breast cancer for the purpose of improving survival, although a major Early Breast Cancer Cooperative Trialists’ Group meta-analysis is underway which may impact future practice. Adverse events can be managed with appropriate supportive care.

Basic research and clinical applications of bisphosphonates in bone disease: what have we learned over the last 40 years?

It is now 40 years since bisphosphonates (BPs) were first used in the clinic. So, it is timely to provide a brief review of what we have learned about these agents in bone disease. BPs are bone-specific and have been classified into two major groups on the basis of their distinct molecular modes of action: amino-BPs and non-amino-BPs. The amino-BPs are more potent and they inhibit farnesyl pyrophosphate synthase (FPPS), a key enzyme of the mavalonate/cholesterol biosynthetic pathway, while the non-amino-BPs inhibit osteoclast activity, by incorporation into non-hydrolyzable analogs of ATP. Both amino-BPs and non-amino-BPs can protect osteoblasts and osteocytes against apoptosis. The BPs are widely used in the clinic to treat various diseases characterized by excessive bone resorption, including osteoporosis, myeloma, bone metastasis, Legg-Perthes disease, malignant hyperparathyroidism, and other conditions featuring bone fragility. This review provides insights into some of the adverse effects of BPs, such as gastric irritation, osteonecrosis of the jaw, atypical femoral fractures, esophageal cancer, atrial fibrillation, and ocular inflammation. In conclusion, this review covers the biochemical and molecular mechanisms of action of BPs in bone, particularly the discovery that BPs have direct anti-apoptotic effects on osteoblasts and osteocytes, and the current situation of BP use in the clinic.

German Adjuvant Intergroup Node-Positive Study: A Phase III Trial to Compare Oral Ibandronate Versus Observation in Patients With High-Risk Early Breast Cancer

Purpose

Bisphosphonates prevent skeletal-related events in patients with metastatic breast cancer. Their effect in early breast cancer is controversial. Ibandronate is an orally and intravenously available amino-bisphosphonate with a favorable toxicity profile. It therefore qualifies as potential agent for adjuvant use.

Patients and Methods

The GAIN (German Adjuvant Intergroup Node-Positive) study was an open-label, randomized, controlled phase III trial with a 2 × 2 factorial design. Patients with node-positive early breast cancer were randomly assigned 1:1 to two different dose-dense chemotherapy regimens and 2:1 to ibandronate 50 mg per day orally for 2 years or observation. In all, 2,640 patients and 728 events were estimated to be required to demonstrate an increase in disease-free survival (DFS) by ibandronate from 75% to 79.5% by using a two-sided α = .05 and 1-β of 80%. We report here the efficacy analysis for ibandronate, which was released by the independent data monitoring committee because the futility boundary was not crossed after 50% of the required DFS events were observed.

Results

Between June 2004 and August 2008, 2,015 patients were randomly assigned to ibandronate and 1,008 to observation. Patients randomly assigned to ibandronate showed no superior DFS or overall survival (OS) compared with patients randomly assigned to observation (DFS: hazard ratio, 0.945; 95% CI, 0.768 to 1.161; P = .589; OS: HR, 1.040; 95% CI, 0.763 to 1.419; P = .803). DFS was numerically longer if ibandronate was used in patients younger than 40 years or older than 60 years compared with patients age 40 to 59 years (test for interaction P = .093).

Conclusion

Adjuvant treatment with oral ibandronate did not improve outcome of patients with high-risk early breast cancer who received dose-dense chemotherapy.

Beyond aspirin-cancer prevention with statins, metformin and bisphosphonates

Cancer risk reduction using pharmacological means is an attractive modern preventive approach that supplements the classical behavioural prevention recommendations. Medications that are commonly used by large populations to treat a variety of common, non-cancer-related, medical situations are an attractive candidate pool. This Review discusses three pharmacological agents with the most evidence for their potential as cancer chemopreventive agents: anti-hypercholesterolaemia medications (statins), an antidiabetic agent (metformin) and antiosteoporosis drugs (bisphosphonates). Data are accumulating to support a significant negative association of certain statins with cancer occurrence or survival in several major tumour sites (mostly gastrointestinal tumours and breast cancer), with an augmented combined effect with aspirin or other non-steroidal anti-inflammatory drugs. Metformin, but not other hypoglycaemic drugs, also seems to have some antitumour growth activity, but the amount of evidence in human studies, mainly in breast cancer, is still limited. Experimental and observational data have identified bisphosphonates as a pharmacological group that could have significant impact on incidence and mortality of more than one subsite of malignancy. At the current level of evidence these potential chemopreventive drugs should be considered in high-risk situations or using the personalized approach of maximizing individual benefits and minimizing the potential for adverse effects with the aid of pharmacogenetic indicators.

Prevention and Treatment of Bone Metastases in Breast Cancer

In breast cancer patients, bone is the most common site of metastases. Medical therapies are the basic therapy to prevent distant metastases and recurrence and to cure them. Radiotherapy has a primary role in pain relief, recalcification and stabilization of the bone, as well as the reduction of the risk of complications (e.g., bone fractures, spinal cord compression). Bisphosphonates, as potent inhibitors of osteoclastic-mediated bone resorption are a well-established, standard-of-care treatment option to reduce the frequency, severity and time of onset of the skeletal related events in breast cancer patients with bone metastases. Moreover bisphosphonates prevent cancer treatment-induced bone loss. Recent data shows the anti-tumor activity of bisphosphonates, in particular, in postmenopausal women and in older premenopausal women with hormone-sensitive disease treated with ovarian suppression. Pain is the most frequent symptom reported in patients with bone metastases, and its prevention and treatment must be considered at any stage of the disease. The prevention and treatment of bone metastases in breast cancer must consider an integrated multidisciplinary approach.

Effect of adjuvant bisphosphonates on disease-free survival in early breast cancer: Retrospective analysis results in an unselected single-center cohort

Bisphosphonates are the gold standard for preventing skeletal-related events in patients with bone-metastatic cancer and have been investigated for reducing cancer treatment-induced bone loss. Evidence suggests bisphosphonates also offer anticancer benefits in adjuvant and advanced cancer settings. We conducted a retrospective analysis of data from a single-center, unselected cohort of women with early breast cancer (N=1646: 962 received adjuvant bisphosphonates, 684 did not) to assess the impact of bisphosphonates on disease-free and overall survival. The bisphosphonate group comprised all women who started bisphosphonate treatment within 1 year of breast cancer diagnosis and received ≥3 months of bisphosphonate treatment (zoledronic acid, clodronate, ibandronate, or alendronate; majority received zoledronic acid). Disease-free survival was defined as the time from breast cancer diagnosis until first disease recurrence or death. Treatment groups were balanced for cancer stage, hormone receptor expression, and human epidermal growth factor receptor-2 expression. Patients in the no-bisphosphonate group were more likely to be ≥75 years of age, node-negative, and have histologic grade 3 tumors. In patients treated with adjuvant bisphosphonates, disease-free survival was significantly longer than in those who did not receive bisphosphonates (P=0.0017). Both disease-free and overall survival were significantly longer in patients with hormone receptor-positive disease irrespective of lymph node status (disease-free survival: P=0.0038; overall survival: P<0.0026). No significant disease-free survival difference was detected in patients with hormone receptor-negative disease. This large, retrospective study demonstrates a significant survival benefit with adjuvant bisphosphonates in patients with early breast cancer, particularly in patients with node-positive and hormone receptor-positive disease.

Adjuvant bone-targeted therapy to prevent metastasis: lessons from the AZURE study

PURPOSE OF REVIEW

Bone-targeted treatments with bisphosphonates (e.g., zoledronic acid) and denosumab are known to reduce the risk of skeletal complications and prevent treatment-induced bone loss in patients with malignant bone disease. Additionally, these drugs may modify the course of bone destruction via inhibitory effects on the 'vicious cycle' of growth factor and cytokine signalling between tumour and bone cells within the bone marrow microenvironment.

RECENT FINDINGS

In early stage breast cancer, treatment with zoledronic acid has shown improvements in disease-free and overall survival, notably in women with established menopause at diagnosis and in premenopausal women with endocrine-responsive disease, treated with goserelin to suppress ovarian function. Other bisphosphonates such as clodronate may produce similar benefits. Additionally, in castrate-resistant prostate cancer, treatment with denosumab delays the development of bone metastases.

SUMMARY

These results strongly support the adjuvant use of bone-targeted treatments, but suggest that reproductive hormones are an important treatment modifier to take into account.

The role of the bone microenvironment in skeletal metastasis

The bone microenvironment provides a fertile soil for cancer cells. It is therefore not surprising that the skeleton is a frequent site of cancer metastasis. It is believed that reciprocal interactions between tumour and bone cells, known as the “vicious cycle of bone metastasis” support the establishment and orchestrate the expansion of malignant cancers in bone. While the full range of molecular mechanisms of cancer metastasis to bone remain to be elucidated, recent research has deepened our understanding of the cell-mediated processes that may be involved in cancer cell survival and growth in bone. This review aims to address the importance of the bone microenvironment in skeletal cancer metastasis and discusses potential therapeutic implications of novel insights.

Bisphosphonates in the adjuvant treatment of breast cancer

Bisphosphonates, as potent inhibitors of osteoclast-mediated bone resorption, significantly reduce the risk of skeletal complications in metastatic bone disease and also prevent cancer treatment-induced bone loss (CTIBL). However, more recently, there has been increasing data indicating that bisphosphonates exhibit anti-tumour activity, possibly via both indirect and direct effects, and can potentially modify the metastatic disease process providing more than just supportive care. The evidence from previous studies of an anti-tumour effect of bisphosphonates was inconclusive, with conflicting evidence from adjuvant oral clodronate trials. However, more recent trials using zoledronic acid have shown benefits in terms of disease-free and overall survival outcomes in certain subgroups, most evidently in older premenopausal women with hormone-sensitive disease treated with ovarian suppression, and in women in established menopause at trial entry. In the adjuvant setting, the use of bisphosphonates has also been focused on the prevention and treatment of CTIBL and recent guidelines have defined treatment strategies for CTIBL. The role of bisphosphonates in CTIBL in early breast cancer is well defined. There have been mixed results from large adjuvant metastasis-prevention studies of bisphosphonates, but there are strong signals from large subgroups analyses of randomised phase III trials suggesting significant anti-tumour beneficial effects in specific patient populations.

Biology of bone metastases

BACKGROUND

Bone metastases cause morbidity and mortality in multiple malignancies. In addition to portending a dire prognosis, bone metastases cause bone pain, fractures, hypercalcemia, spinal cord compression, and other nerve compression syndromes. Improved understanding of the mechanisms that predispose tumor metastases to bone is needed to improve patients' therapeutic options, maintain their quality of life, and improve their survival.

METHODS

This review discusses selected preclinical and clinical data regarding bone metastasis development and cytokine/molecular interactions predisposing to bone metastases formation. Potential interventions for reducing bone metastases are also described.

RESULTS

Biologic mechanisms resulting in metastases of tumor cells to bone are being studied. Among these are the RANKL pathway, osteoclast activation via cytokines (produced by tumor cell and cells in the bone microenvironment), interactions with transient and stromal cells in the bone microenvironment, and molecules such as PTHrP and endothelin-1. These molecules offer important opportunities for targeted interventions to decrease bone metastases-associated morbidity.

CONCLUSIONS

Knowledge of the pathophysiology of bone and cancer is developing rapidly. Relationships among cancer cells, bone-derived cells, and cytokines provide opportunities for the development of new interventions. Therapy targeting osteoclast/osteoblast interactions has proven benefit for patients with bone metastases.

Effects of bone-targeted agents on cancer progression and mortality

Bone-targeted treatments with bisphosphonates and denosumab, which reduce bone resorption, are known to reduce the risk of skeletal complications and prevent treatment-induced bone loss in patients with malignant bone disease. Additionally, these drugs may modify the course of bone destruction via inhibitory effects on the "vicious cycle" of growth factor and cytokine signaling between tumor and bone cells within the bone marrow microenvironment. Effects of the drugs on the stem cell niche, direct effects on the cancer cells, and immune modulation may also contribute. In early-stage (stages I, II, and III) breast cancer, treatment with the bisphosphonate zoledronic acid has shown improvements in disease-free and overall survival. Improved survival was particularly notable in women with established menopause at diagnosis and in premenopausal women with endocrine-responsive disease who received treatment with goserelin, which suppresses ovarian function by inhibiting the production of ovarian hormones. Additionally, in castrate-resistant prostate cancer, treatment with denosumab delays the development of bone metastases. These results strongly support the adjuvant use of bone-targeted treatments but suggest that reproductive hormones are an important treatment modifier to take into account. In advanced-stage (stage IV, ie, metastatic) cancers, survival benefits have been observed in patients with multiple myeloma and in patients with other solid tumors with rapid rates of bone destruction who received treatment with zoledronic acid. Here, we have critically reviewed the increasing evidence to support a disease-modifying effect of bone-targeted treatment and discussed the impact on clinical management.

Breast Cancer 2012 - New Aspects

Treatment options as well as the characteristics for therapeutic decisions in patients with primary and advanced breast cancer are increasing in number and variety. New targeted therapies in combination with established chemotherapy schemes are broadening the spectrum, however potentially promising combinations do not always achieve a better result. New data from the field of pharmacogenomics point to prognostic and predictive factors that take not only the properties of the tumour but also inherited genetic properties of the patient into consideration. Current therapeutic decision-making is thus based on a combination of classical clinical and modern molecular biomarkers. Also health-economic aspects are more frequently being taken into consideration so that health-economic considerations may also play a part. This review is based on information from the recent annual congresses. The latest of these are the 34th San Antonio Breast Cancer Symposium 2011 and the ASCO Annual Meeting 2012. Among their highlights are the clinically significant results from the CLEOPATRA, BOLERO-2, EMILIA and SWOG S0226 trials on the therapy for metastatic breast cancer as well as further state-of-the-art data on the adjuvant use of bisphosphonates within the framework of the ABCSG-12, ZO-FAST, NSABP-B34 and GAIN trials.

Oral clodronate for adjuvant treatment of operable breast cancer (National Surgical Adjuvant Breast and Bowel Project protocol B-34): a multicentre, placebo-controlled, randomised trial

BACKGROUND

Bisphosphonates are thought to act through the osteoclast by changing bone microenvironment. Previous findings of adjuvant clodronate trials in different populations with operable breast cancer have been mixed. The National Surgical Adjuvant Breast and Bowel Project (NSABP) protocol B-34 aims to ascertain whether oral clodronate can improve outcomes in women with primary breast cancer.

METHODS

NSABP B-34 is a multicentre, randomised, double-blind, placebo-controlled study in 3323 women with stage 1-3 breast cancer. After surgery to remove the tumour, patients were stratified by age, axillary nodes, and oestrogen and progesterone receptor status and randomly assigned in a 1:1 ratio to either oral clodronate 1600 mg daily for 3 years (n=1662) or placebo (1661). The primary endpoint was disease-free survival, analysed by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00009945.

FINDINGS

Median follow-up was 90·7 months (IQR 82·7-100·0) and 3311 patients had data for this period. Disease-free survival did not differ between groups (286 events in the clodronate group vs 312 in the placebo group; hazard ratio 0·91, 95% CI 0·78-1·07; p=0·27). Moreover, no differences were recorded for overall survival (0·84, 0·67-1·05; p=0·13), recurrence-free interval (0·83, 0·67-1·04; p=0·10), or bone metastasis-free interval (0·77, 0·55-1·07; p=0·12). Non-bone metastasis-free interval was slightly increased with clodronate (0·74, 0·55-1·00; p=0·047). Analyses in women age 50 years or older on study entry showed benefits of clodronate for recurrence-free interval (0·75, 0·57-0·99; p=0·045), bone metastasis-free interval (0·62, 0·40-0·95; p=0·027), and non-bone metastasis-free interval (0·63, 0·43-0·91; p=0·014), but not for overall survival (0·80, 0·61-1·04, p=0·094). Adherence to treatment at 3 years was 56% for the clodronate group and 60% for the placebo group. Grade 3 or higher liver dysfunction was noted in 23 of 1612 patients in the clodronate group and 12 of 1623 patients in the placebo group; grade 3-4 diarrhoea was noted in 28 patients in the clodronate group and in ten in the placebo group. There was one possible case of osteonecrosis of the jaw in the clodronate group.

INTERPRETATION

Findings of NSABP B-34 suggest that bisphosphonates might have anticancer benefits for older postmenopausal women. A meta-analysis of adjuvant bisphosphonate trials is suggested before recommendations for use in non-osteoporotic postmenopausal women with primary breast cancer are made.

FUNDING

National Cancer Institute, Bayer Oy (formerly Schering Oy).

Demographic and clinico-pathological characteristics of breast cancer patients with history of oral alendronate use

Bisphosphonates are the most commonly used agents in the treatment of osteoporosis, and bisphosphonate therapy reduces the risk of skeletally related complications in patients with bone metastases due to malignancy. However, the effect of oral alendronate treatment on clinical and pathological properties of breast cancer has not been reported. Thus, we aimed to investigate retrospectively the demographic and clinico-pathological characteristics of new diagnosis of breast cancer patients with oral alendronate users for longer than 1 year, compared with non-users. Newly diagnosed breast cancer patients from 1998 to 2010 in our clinic were retrospectively analyzed. Patient's demographics, including survival data and tumor characteristics, were obtained from medical charts. Breast cancer patients who were taking oral alendronate more than 12 months at the time of breast cancer diagnosis were enrolled as an alendronate users (n=44), where the patients matched with the same age who were not taking oral alendronate were included as a control group (n=444). A total of 488 patients were included in this study. Forty-four patients received an oral alendronate treatment more than 1 year, and 444 patients were considered as non-users. Median age of both alendronate users and non-users was 57 (33-89). Lower incidence of histological grade III, T3-T4 tumor, and node positivity was seen in alendronate users but not statistically significant. A similar trend for lower incidence of triple negative and higher incidence ER (P=0.13), progesterone receptor (P=0.12), and HER2 positivity (P=0.21) was also seen in alendronate users but not statistically significant. Estimated median disease-free survival was 150 months in alendronate users where as 70 months in non-users (P=0.015). Five-year survival rate in alendronate users was 97.4%, whereas in non-users was 89.8% (P=0.13). The use of oral alendronate for longer than 1 year at the time of breast cancer diagnosis was associated with better clinico-pathological properties and significantly improved disease-free survival in breast cancer patients.

Seed, soil and secreted hormones: potential interactions of breast cancer cells with their endocrine/paracrine microenvironment and implications for treatment with bisphosphonates

The process of formation of metastasis is undoubtedly inefficient, with the majority of disseminated tumour cells perishing in their metastatic environment. Their ability to survive is determined by their intrinsic abilities, with emerging evidence of the importance of cancer stem cells possessing self propagating potential, but also the interaction with the premetastatic niche, which may either help or hinder their formation into micrometastasis, thus influencing recurrence and survival in breast cancer patients. Use of the bone targeted agents bisphosphonates in the adjuvant setting has been extensively studied in large clinical trials, and demonstrated an interesting interplay with the endocrine microenvironment, with postmenopausal women or premenopausal women receiving ovarian suppression therapy gaining a survival advantage compared to pre/perimenopausal women. The interaction between the endocrine hormones and the paracrine TGFβ growth factors may provide an explanation for the differences seen according to ovarian function in the response to bisphosphonates. In this review the evidence of interplay between ovarian endocrine hormones, TGFβ paracrine growth factors and bisphosphonates will be presented, and subsequent influence on breast cancer cells in the bone pre-metastatic niche hypothesised.

Antiresorptive therapies in oncology and their effects on cancer progression

Bone health is an emerging concern in the early breast cancer setting. Current adjuvant therapies, especially hormonal therapies in premenopausal patients (e.g. goserelin) and aromatase inhibitors in postmenopausal patients, have been associated with substantial decreases in bone mineral density that may place patients at risk for fractures. Bisphosphonates--and the recently approved anti-RANKL antibody, denosumab--have both demonstrated activity for the treatment of postmenopausal osteoporosis and cancer treatment-induced bone loss (CTIBL) in breast cancer patients, although neither has received widespread approval specifically for CTIBL. However, some bisphosphonates, especially the nitrogen-containing bisphosphonate zoledronic acid, have also demonstrated clinically meaningful anticancer effects in patients receiving adjuvant hormonal therapy for breast cancer and in other oncology settings. The effects of denosumab on cancer disease outcomes in the adjuvant setting remain to be established. This discrepancy has created a dilemma in terms of how to evaluate the complete benefit:risk profile of bone-health management options in the adjuvant breast cancer setting. This review summarises the current data on the course of cancer in clinical trials of the antiresorptive agents and provides important insight into the relative anticancer potential of the various therapies.

Bisphosphonates and other bone agents for breast cancer

BACKGROUND

Bone is the most common site of metastatic disease associated with breast cancer (BC). Bisphosphonates inhibit osteoclast-mediated bone resorption, and novel targeted therapies such as denosumab, inhibit key pathways in the vicious cycle of bone metastases.

OBJECTIVES

To assess the effect of bisphosphonates on skeletal-related events (SREs), bone pain, quality of life (QoL), recurrence and survival in women with breast cancer with bone metastases (BCBM), advanced breast cancer (ABC) without clinical evidence of bone metastases and early breast cancer (EBC).To assess the effect of denosumab on SREs, bone pain and (QoL) in women with (BCBM).

SEARCH METHODS

We searched the Specialised Register maintained by the Cochrane Breast Cancer Group (CBCGSR), MEDLINE, EMBASE and the WHO International Cancer Trials Registry Platform (WHO ICTRP) on 30 April 2011. We conducted additional handsearching of journals and proceedings of key meetings.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing: (a) bisphosphonates and control, or different bisphosphonates in women with BCBM; (b) denosumab and bisphosphonates in women with BCBM; (c) bisphosphonates and control in women with ABC; (d) bisphosphonates and control in women with EBC; and (e) early versus delayed bisphosphonate treatment in women with EBC.

DATA COLLECTION AND ANALYSIS

Two review authors (MW and NP) independently assessed the trials and extracted the data. We collected toxicity information from the trials.

MAIN RESULTS

We included thirty-four RCTs. In nine studies (2806 patients with BCBM), comparing bisphosphonates with placebo or no bisphosphonates, bisphosphonates reduced the SRE risk by 15% (risk ratio (RR) 0.85; 95% confidence interval (CI) 0.77 to 0.94; P = 0.001). This benefit was most certain with intravenous (i.v.) zoledronic acid (4 mg) (RR 0.59; 95% CI 0.42 to 0.82); i.v. pamidronate (90 mg) (RR 0.77; 95% CI 0.69 to 0.87); and i.v. ibandronate (RR 0.80; 95% CI 0.67 to 0.96). A direct comparison of i.v. zoledronic acid and i.v. pamidronate confirmed at least equivalent efficacy in a single large study. In three studies (3405 patients with BCBM), compared with bisphosphonates, subcutaneous (s.c.) denosumab was more effective in reducing the risk of SREs (RR 0.78; 95% CI 0.72 to 0.85; P < 0.00001).Bisphosphonates reduced the SRE rate in 12 studies (median reduction 28%, range 14% to 48%), with statistically significant reductions reported in 10 studies. Women with BCBM treated with bisphosphonates showed significant delays in the median time to SREs. Compared with placebo or no bisphosphonates, treatment with bisphosphonates significantly improved bone pain in six out of eleven studies. Improvements in global QoL with bisphosphonates compared to placebo were reported in two out of five studies (both ibandronate studies). Treatment with bisphosphonates did not appear to affect survival in women with BCBM. Compared to i.v. zoledronic acid, denosumab also significantly reduced the SRE rate, delayed the time to SREs and prolonged the time in developing pain for patients with no or mild pain at baseline; but there was no difference in survival between patients treated with denosumab and zoledronic acid.Bisphosphonates in women with ABC without clinically evident bone metastases did not reduce the incidence of bone metastases, or improve survival in three studies (320 patients).In seven studies (7847 patients with EBC), currently there is no evidence supporting bisphosphonates in reducing the incidence of bone metastases compared to no bisphosphonates (RR 0.94; 95% CI 0.82 to 1.07; P = 0.36). In three studies (2190 patients with EBC), early bisphosphonate treatment also did not significantly reduce the incidence of bone metastases compared to delayed bisphosphonate treatment (RR 0.73; 95% CI 0.40 to 1.33; P = 0.31). Currently, there is insufficient evidence to make a conclusion about the role of adjuvant bisphosphonates in reducing visceral metastases, locoregional recurrence and total recurrence, or improving survival. There was strong heterogeneity in EBC studies examining the outcomes of total recurrence and survival.Reported toxicity was generally mild. Renal toxicity and osteonecrosis of the jaw (ONJ) have been identified as potential problems with bisphosphonate use. ONJ was reported at similar rates for patients on denosumab compared to zoledronic acid. This highlighted a need for maintaining good oral care, prior to and during treatment, for patients who received long-term bone agents.

AUTHORS' CONCLUSIONS

In women with clinically evident BCBM, bisphosphonates (oral and i.v.) and denosumab (s.c.) reduced the risk of developing SREs, as well as delaying the time to SREs. Some bisphosphonates may also reduce bone pain and may improve QoL. The optimal timing and duration of treatment for patients with BCBM remains uncertain. There is currently insufficient evidence to support the routine use of bisphosphonates as adjuvant treatment for patients with EBC. However, a number of large clinical trials investigating bisphosphonates in EBC have completed accrual and are awaiting results.

Bisphosphonates and pathologic complete response to taxane- and anthracycline-based neoadjuvant chemotherapy in patients with breast cancer

BACKGROUND

Several studies have suggested that bisphosphonates have an antitumor effect. In the current study, the authors sought to evaluate whether the use of bisphosphonates increased the rate of pathological complete response (pCR) in patients with breast cancer.

METHODS

The authors identified 1449 patients with breast cancer who were receiving taxane- and anthracycline-based neoadjuvant chemotherapy between 1995 and 2007 at The University of Texas MD Anderson Cancer Center. Patients who received bisphosphonates for osteopenia or osteoporosis while receiving chemotherapy were also identified. The primary outcome was the percentage of patients achieving a pCR. Groups were compared using the chi-square test. A multivariable logistic regression model was fit to examine the relation between the use of bisphosphonates and pCR. An exploratory survival analysis using the Kaplan-Meier method was performed; groups were compared using the log-rank test.

RESULTS

Of the 1449 patients included, 39 (2.7%) received bisphosphonates. Those receiving bisphosphonates were older (P < .001) and less likely to be obese (P = .04). The pCR rate was 25.4% in the bisphosphonate group and 16% in the nonbisphosphonate group (P = .11). In the multivariable model, patients treated with bisphosphonates tended to have higher rates of pCR (odds ratio, 2.18; 95% confidence interval, 0.90-5.24); however, the difference was not found to be statistically significant. With a median follow-up of 55 months (range, 3 months-145 months), no differences in disease recurrence or survival were observed.

CONCLUSIONS

The use of bisphosphonates at the time of neoadjuvant chemotherapy was not found to be associated with a statistically significant increase in the rates of pCR. The observed estimates suggest a positive effect; however, the small percentage of patients receiving bisphosphonates likely affected the power to detect a statistically significant difference.

Bisphosphonates: prevention of bone metastases in breast cancer

Disease recurrence and distant metastases remain challenging for patients with breast cancer despite advances in early diagnosis, surgical expertise, and adjuvant therapy. Bone is the most common site for breast cancer metastasis, and the bone microenvironment plays a crucial role in harboring disseminated tumor cells (DTCs), a putative source of late relapse in and outside bone. Therefore, agents that affect bone metabolism might not only prevent the development of bone lesions but also provide meaningful reductions in the risk of relapse both in bone and beyond. Bisphosphonates bind to mineralized bone surfaces and are ingested by osteoclasts, wherein they inhibit osteolysis, thereby preventing the release of growth factors from the bone matrix. Therefore, the bone microenvironment becomes less conducive to survival and growth of DTCs and bone lesion formation. Recent trials of zoledronic acid in the adjuvant setting in breast cancer have demonstrated reduced disease recurrence in bone and other sites in premenopausal and postmenopausal women with early breast cancer. Based on the proven effect of bone protection during adjuvant endocrine therapy, new treatment guidelines recommend the routine use of bisphosphonates to prevent bone loss during adjuvant therapy, which may likely become the standard practice.

Significance of combination therapy of zoledronic acid and gemcitabine on pancreatic cancer

In the present study, we examined the cytotoxic effects of combination therapy with zoledronic acid (ZOL) and gemcitabine (GEM) on pancreatic cancer cells in vitro and in vivo. Four human pancreatic cancer cell lines were treated with ZOL, GEM or a combination of both, and the effects of the respective drug regimens on cell proliferation, invasion and matrix metalloproteinase (MMP) expression were examined. A pancreatic cancer cell line was also intrasplenically or orthotopically implanted into athymic mice and the effects of these drugs on tumor metastasis and growth in vivo were evaluated by histological and immunohistochemical analyses. Combination treatment with low doses of ZOL and GEM efficiently inhibited the proliferation (P < 0.001) and invasion (P < 0.001) of pancreatic cancer cells in vitro. Western blotting assay revealed that MMP-2 and MMP-9 expression levels were decreased after ZOL treatment. In vivo, combined treatment significantly inhibited tumor growth (P < 0.05) and the development of liver metastasis (P < 0.05). These data revealed that ZOL and GEM, when used in combination, have significant antitumor, anti-metastatic and anti-angiogenic effects on pancreatic cancer cells. The present study is the first to report the significance of the combination treatment of ZOL and GEM in pancreatic cancer using an in vivo model. These data are promising for the future application of this drug regimen in patients with pancreatic cancer.

Retrospective analysis of antitumor effects of zoledronic acid in breast cancer patients with bone-only metastases

BACKGROUND

Bisphosphonates have been used successfully in the treatment of hypercalcemia and to reduce skeletal complications of bone metastasis, but have not been shown to prevent bone metastasis or to prolong survival time in metastatic breast cancer patients. The aim of this study was to determine whether the progression-free survival (PFS) and overall survival (OS) of patients with bone-only breast cancer metastasis differed based on whether patients received zoledronic acid, pamidronate, or no bisphosphonate upon diagnosis of their metastases.

PATIENTS AND METHODS

We retrospectively identified 314 patients diagnosed with bone-only metastasis at the time of initial staging or who developed bone metastasis as the first recurrence site during follow-up from January 1, 1997 to December 31, 2008, at The MD Anderson Cancer Center. Univariate and multivariate Cox hazards models were used to assess the effects of each treatment on PFS and OS.

RESULTS

Patients who had more than 1 bone metastasis and Eastern Cooperative Oncology Group (ECOG) performance status of 2 and 3 were more likely to receive zoledronic acid in this analysis. Compared with no bisphosphonate use, the use of zoledronic acid was not significantly associated with longer PFS (hazard ratio [HR] = 0.72, P = .058 in univariate analysis, and HR = 0.80, P = .235 in multivariate analysis) nor with longer OS (HR = 1.04, P = .863 in univariate analysis and HR = 1.34, P = .192 in multivariate analysis).

CONCLUSION

Our study demonstrates that for patients with bone-only metastases, zoledronic acid did not prolong PFS or OS. In patients with bone-only metastasis, we could not demonstrate antitumor effects of zoledronic acid.

New developments for treatment and prevention of bone metastases

PURPOSE OF REVIEW

To provide a critical review of recent trials of bone resorption inhibitory drugs (bisphosphonates and denosumab) for the treatment and the prevention of bone metastases in solid tumors.

RECENT FINDINGS

The bisphosphonate zoledronic acid is now part of the standard treatment for metastatic bone disease. Comparative trials in this setting between zoledronic acid and denosumab have shown superior (in breast and in prostate cancer) or noninferior (in other solid tumors) skeletal-related event-prevention activity for denosumab. Osteonecrosis of the jaw is the most important side-effect of both compounds. Recent data also indicate the potential of zoledronic acid to reduce the recurrence rate in breast cancer.

SUMMARY

Much progress has been accomplished for the treatment of tumor bone disease with bone resorption inhibitory drugs. Advances are now awaited in the setting of prevention of bone metastases.

Use of ibandronate in the prevention of skeletal events in metastatic breast cancer

Bone metastasis from breast cancer often cause significant morbidity including pain, impaired mobility, pathological fracture, and spinal cord compression. Bisphosphonates play an important role in preventing these skeletal related events and are the standard of care for patients with bone metastasis from breast cancer. Ibandronate is a highly potent bisphosphonate available in both intravenous and oral preparations. It has been shown in clinical trials to be effective in reducing skeletal complications and also significantly improve quality of life up to 96 weeks. Unlike other intravenous bisphosphonates, ibandronate has minimal renal toxicity, allowing safe outpatient administration, reducing the need for hospital attendance and safety monitoring. Early trials have shown ibandronate may also be effective in high doses for palliation of opioid-resistant pain from bone metastasis, and as a second-line agent in patients developing a skeletal complication whilst receiving another bisphosphonate.

Optimal management of bone metastases in breast cancer patients

Bone metastasis in breast cancer is a significant clinical problem. It not only indicates incurable disease with a guarded prognosis, but is also associated with skeletal-related morbidities including bone pain, pathological fractures, spinal cord compression, and hypercalcemia. In recent years, the mechanism of bone metastasis has been further elucidated. Bone metastasis involves a vicious cycle of close interaction between the tumor and the bone microenvironment. In patients with bone metastases, the goal of management is to prevent further skeletal-related events, manage complications, reduce bone pain, and improve quality of life. Bisphosphonates are a proven therapy for the above indications. Recently, a drug of a different class, the RANK ligand antibody, denosumab, has been shown to reduce skeletal-related events more than the bisphosphonate, zoledronic acid. Other strategies of clinical value may include surgery, radiotherapy, radiopharmaceuticals, and, of course, effective systemic therapy. In early breast cancer, bisphosphonates may have an antitumor effect and prevent both bone and non-bone metastases. Whilst two important Phase III trials with conflicting results have led to controversy in this topic, final results from these and other key Phase III trials must still be awaited before a firm conclusion can be drawn about the use of bisphosphonates in this setting. Advances in bone markers, predictive biomarkers, multi-imaging modalities, and the introduction of novel agents have ushered in a new era of proactive management for bone metastases in breast cancer.

Zoledronic acid use in cancer patients: more than just supportive care?

Bone is the most common site for metastasis from solid tumors, and the majority of patients will develop bone metastases during the natural course of their disease. Bisphosphonates are an effective treatment for preventing skeletal-related events in patients with bone metastases and may preserve functional independence and quality of life. Although several bisphosphonates have been investigated in patients with solid tumors, only zoledronic acid (ZOL) is approved by the US Food and Drug Administration and the European Medicines Agency for preventing skeletal-related events in patients across a broad range of solid tumors. In addition, bisphosphonates, notably ZOL, prevent cancer treatment-induced bone loss in breast and prostate cancer patients who are receiving endocrine therapy. It also has been demonstrated that ZOL directly and indirectly inhibits cancer cell growth in vitro and growth and tumorigenesis in animal model systems. These properties may produce clinically meaningful benefits. In recent clinical studies in patients with cancer, ZOL improved overall and prolonged disease-free survival. Ongoing clinical trials in patients with solid tumors will provide further insight into the potential of ZOL to prevent distant metastases and improve survival.

Use of bisphosphonates and reduced risk of colorectal cancer

PURPOSE

Bisphosphonates are commonly used for the treatment of osteoporosis and bone metastases caused by breast cancer and were recently reported to be associated with a reduced risk of breast cancer, possibly acting through the mevalonate pathway, but their association with risk of other cancers is unknown.

PATIENTS AND METHODS

The Molecular Epidemiology of Colorectal Cancer study is a population-based, case-control study in northern Israel of patients with colorectal cancer and age-, sex-, clinic-, and ethnic group-matched controls. Long-term use of bisphosphonates before diagnosis was assessed in a subset of 933 pairs of postmenopausal female patients and controls, enrolled in Clalit Health Services, using computerized pharmacy records.

RESULTS

The use of bisphosphonates for more than 1 year before diagnosis, but not for less than 1 year, was associated with a significantly reduced relative risk (RR) of colorectal cancer (RR, 0.50; 95% CI, 0.35 to 0.71). This association remained statistically significant after adjustment in a model for vegetable consumption, sports activity, family history of colorectal cancer, body mass index, and use of low-dose aspirin, statins, vitamin D, and postmenopausal hormones (RR, 0.41; 95% CI, 0.25 to 0.67). Concomitant use of bisphosphonates and statins did not further reduce the risk.

CONCLUSION

The use of oral bisphosphonates for more than 1 year was associated with a 59% relative reduction in the risk of colorectal cancer, similar to the recently reported association of this drug class with reduction in breast cancer risk.

Use of bisphosphonates and reduced risk of colorectal cancer

PURPOSE

Bisphosphonates are commonly used for the treatment of osteoporosis and bone metastases caused by breast cancer and were recently reported to be associated with a reduced risk of breast cancer, possibly acting through the mevalonate pathway, but their association with risk of other cancers is unknown.

PATIENTS AND METHODS

The Molecular Epidemiology of Colorectal Cancer study is a population-based, case-control study in northern Israel of patients with colorectal cancer and age-, sex-, clinic-, and ethnic group-matched controls. Long-term use of bisphosphonates before diagnosis was assessed in a subset of 933 pairs of postmenopausal female patients and controls, enrolled in Clalit Health Services, using computerized pharmacy records.

RESULTS

The use of bisphosphonates for more than 1 year before diagnosis, but not for less than 1 year, was associated with a significantly reduced relative risk (RR) of colorectal cancer (RR, 0.50; 95% CI, 0.35 to 0.71). This association remained statistically significant after adjustment in a model for vegetable consumption, sports activity, family history of colorectal cancer, body mass index, and use of low-dose aspirin, statins, vitamin D, and postmenopausal hormones (RR, 0.41; 95% CI, 0.25 to 0.67). Concomitant use of bisphosphonates and statins did not further reduce the risk.

CONCLUSION

The use of oral bisphosphonates for more than 1 year was associated with a 59% relative reduction in the risk of colorectal cancer, similar to the recently reported association of this drug class with reduction in breast cancer risk.

Treatment and prevention of bone complications from prostate cancer

Bone metastases and skeletal complications are major causes of morbidity in prostate cancer patients. Despite the osteoblastic appearance of bone metastases on imaging studies, patients have elevated serum and urinary markers of bone resorption, indicative of high osteoclast activity. Increased osteoclast activity is independently associated with higher risk of subsequent skeletal complications, disease progression, and death. Osteoclast-targeted therapies are therefore a rational approach to reduction of risk for disease-related skeletal complications, bone metastases, and treatment-related fractures. This review focuses on recent advances in osteoclast-targeted therapy in prostate cancer. Bisphosphonates have been extensively studied in men with prostate cancer. Zoledronic acid significantly decreased the risk of skeletal complications in men with castration-resistant prostate cancer and bone metastases, and it is FDA-approved for this indication. Denosumab is a human monoclonal antibody that binds and inactivates RANKL, a critical mediator of osteoclast differentiation, activation, and survival. Recent global phase 3 clinic trials demonstrated an emerging role for denosumab in the treatment of prostate cancer bone metastases and prevention of fractures associated with androgen deprivation therapy.

The crossover of bisphosphonates to cancer therapy

Bisphosphonates form a class of drugs commonly used to treat disorders of osteoclastic bone resorption, including osteoporosis, Paget's disease of the bone, rheumatoid arthritis, and bone metastases. Although long established as the therapy of choice to treat such disorders, bisphosphonates' potential in treating cancer is garnering interest. Bisphosphonates have been demonstrated to inhibit tumor growth and metastasis, induce apoptosis in tumor cells, and encourage immune reactions against tumor cells. Current applications of bisphosphonates in cancer treatment include their use to treat skeletal metastases and as an adjuvant to endocrine therapy. This review explores bisphosphonates' current clinical utility and potential as a crossover cancer therapy.

Antitumor effects and anticancer applications of bisphosphonates

Bisphosphonates are firmly entrenched in the treatment of metastatic bone disease secondary to several tumor types, including breast cancer, prostate cancer, and myeloma. More recently, an emerging body of preclinical and clinical evidence indicates that bisphosphonates might also exhibit antitumor activity. This expanded role for bisphosphonates in the adjuvant setting might have profound clinical implications in many cancer types, particularly in the context of prevention of bone metastasis. Increased understanding of the mechanistic basis of the antitumor effects indicates that these might occur via direct mechanisms such as induction of apoptosis and inhibition of tumor cell adhesion and invasion, as well as indirect mechanisms such as inhibition of angiogenesis. There is also considerable evidence to suggest that nitrogen-containing bisphosphonates might exert additive or synergistic interactions with standard cytotoxic agents. However, mature clinical data with bisphosphonates are limited and, thus far, provide conflicting evidence regarding the antitumor role of bisphosphonates, but have mostly been conducted with first-generation bisphosphonates such as clodronate that are not as effective as next-generation bisphosphonates. Several large randomized clinical trials are ongoing with the next-generation bisphosphonate zoledronic acid to prospectively confirm an antitumor role for bisphosphonates in various tumor types. This review assesses the current body of preclinical and clinical evidence in favor of an antitumor effect of bisphosphonates in different cancer types.

Understanding and optimizing bone health in breast cancer

Bone is the preferred site of metastasis for breast cancer, and presence of skeletal lesions is associated with significant morbidity and poor prognosis. Skeletal-related effects such as pain, pathologic fractures, spinal compression, and hypercalcemia are frequent consequences of skeletal lesions of breast cancer that have debilitating effects on the patients' quality of life. In addition to direct cancer effects on the skeleton, therapies commonly used to treat patients with breast cancer such as chemotherapy and aromatase inhibitors (AI) result in cancer therapy-induced bone loss (CTIBL) which is associated with increased risk of skeletal complications such as fractures. Bisphosphonates are a class of antiresorptive drugs that are now firmly established as the cornerstone of the management of skeletal-related events due to breast cancer. Other novel bone-targeting agents such as the anti-receptor activator of NF-κB ligand (RANKL) monoclonal antibody denosumab are also showing promising activity in the treatment of bone metastasis secondary to breast cancer. Moreover, recent provocative evidence suggests that bisphosphonates might also exhibit antitumor activity via direct and indirect mechanisms. The goal of this review is to summarize the pathophysiology of osteolytic bone lesions secondary to breast cancer, provide clinical evidence of currently available bone-targeted drugs in the treatment of bone metastasis and CTIBL, and explore the antitumor activity of current bone-targeted agents in patients with breast cancer.

Randomized trial of adjuvant zoledronic acid in postmenopausal women with high-risk breast cancer

PURPOSE

We present the results of a randomized multicenter clinical trial of adjuvant zoledronic acid (ZA) in postmenopausal women with high-risk breast cancer. The primary objective was change in bone mineral density (BMD) at the lumbar spine and femoral neck at 1 year. Secondary objectives included change in calcaneal BMD, disease-free survival (DFS), overall survival (OS), and toxicity.

PATIENTS AND METHODS

Postmenopausal women with stage II/III breast cancer diagnosed up to 5 years previous were eligible and randomized to either observation or ZA 4 mg intravenous every 3 months. Bone mineral density testing was performed at 0, 6, and 12 months.

RESULTS

Sixty-eight women were enrolled (36 ZA and 32 observation). The population was a median of 2 years from diagnosis and the majority received tamoxifen during the study. There was a significant difference in the mean change from baseline to 1 year follow-up for lumbar spine (increased by 4.28% ± 0.62%; P = .01), total femur (increased by 1.9% ± 0.4%; P = .03), trochanter (increased by 2.97% ± 0.69%; P = .03), and calcaneal BMD (increased by 2% ± 0.57%; P = .01) in favor of the ZA arm. No significant difference in the mean change for the femoral neck was seen. No significant differences in DFS or OS were observed.

CONCLUSION

Zoledronic acid significantly improved the BMD at multiple skeletal sites in postmenopausal women largely on tamoxifen. No new safety signals were noted. There were insufficient events to comment on DFS or OS.

Contemporary therapeutic approaches targeting bone complications in prostate cancer

Skeletal complications are major causes of morbidity in patients with prostate cancer. Despite the osteoblastic appearance of prostate cancer bone metastases, elevated serum and urinary markers of bone resorption are indicative of high osteoclast activity. Increased osteoclast activity is independently associated with subsequent skeletal complications, disease progression, and death. Osteoclast-targeted therapies aim to reduce the risk for disease-related skeletal complications, bone metastases, and treatment-related fractures. This review focuses on recent advances in osteoclast-targeted therapies in the treatment and prevention of bone complications in prostate cancer. Osteoclast-targeted therapies have been extensively studied in men with prostate cancer. The potent bisphosphonate zoledronic acid significantly decreased the risk of skeletal complications in men with castration-resistant prostate cancer and bone metastases, and is Federal Drug Administration approved for this indication. Denosumab is a human monoclonal antibody that inhibits receptor activator of nuclear factor-κB (RANK) ligand, a critical mediator of osteoclast differentiation, activation, and survival. Data from recent phase III clinic trials demonstrate the emerging role for denosumab in the treatment of prostate cancer bone metastases and prevention of fractures associated with androgen deprivation therapy.

[Bisphosphonates in adjuvant therapy of breast cancer]

For more than 10 years, based on the results with the bisphosphonate clodronic acid, it has been discussed, whether the occurrence of breast cancer metastases can be avoided or at least delayed by administration of bisphosphonates. The published results of recent studies applying, e.g., the bisphosphonates zoledronic and ibandronic acid, respectively, seem promising at first glance, especially, if the therapeutic acceptance of bisphosphonates in the indications osteoporosis and bone-related complications of malignancies, respectively, as well as their spectrum of side effects are taken into account and their putative mechanism of action is considered. There is a broad consensus that the existing data basis suffices to demonstrate importance of bisphosphonates in an adjuvant therapeutic setting of breast cancer. Significant relative risk reductions of, e.g., 36% in disease-free survival are very impressing and the corresponding absolute values of 3.2% are second-line communications. However, evaluation of all studies published so far according to the criteria of evidence-based medicine demonstrates many open questions and several methodical insufficiencies. Therefore, effectiveness and benefit of an adjuvant therapeutic application of bisphosphonates in breast cancer patients cannot be drawn out of evidence-based data. A recommendation of this therapy is given only by the German Working Pool of Gynecologic Oncology (AGO), but limited to study participation.

Challenges in clinical patient management

The use of endocrine therapy in breast cancer represents one of the earliest molecular targeting strategies used in cancer treatment. Tamoxifen, a selective estrogen-receptor (ER) modulator, has been the standard of care for women with receptor-positive breast cancer for the last 30 years. Tamoxifen suppresses the estrogen-dependent growth of breast cancer cells by specifically targeting the ER. Because of estrogenic effects, tamoxifen does not increase the risk of osteoporosis, but it can lead to endometrial cancer and thromboembolism. The third-generation aromatase inhibitors (AIs) exert their tumor antiproliferative action by targeting an enzyme critical for estrogen biosynthesis. The AIs thus have a different mechanism of action than tamoxifen, and a different safety profile. The majority of adverse events (AEs) related to the AIs are mild to moderate. Most of these AEs are common to menopause and are predictable and manageable. This review looks at AI-associated side effects and current clinical management strategies, with a particular emphasis on managing bone health. Compliance with long-term therapy, strategies to improve adherence, and considerations in elderly patients with hormone-responsive breast cancer are also discussed.

An open cohort study of bone metastasis incidence following surgery in breast cancer patients

Background

To help design clinical trials of adjuvant bisphosphonate therapy for breast cancer, the temporal incidence of bone metastasis was investigated in a cohort of patients. We have tried to draw the criteria to use adjuvant bisphosphonate.

Methods

Consecutive breast cancer patients undergoing surgery between 1988 and 1998 (5459 patients) were followed up regarding bone metastasis until December 2006. Patients' characteristics at the time of surgery were analyzed by Cox's method, with bone metastasis as events. Patient groups were assigned according to Cox's analysis, and were judged either to require the adjuvant bisphosphonate or not, using the tentative criteria: high risk (>3% person-year), medium risk (1-3%), and low risk (<1%).

Results

Bone metastasis incidence was constant between 1.0 and 2.8% per person-year more than 10 years. Non-invasive cancer was associated with a very low incidence of bone metastasis (1/436). Multivariate Cox's analysis indicated important factors for bone metastasis were tumor grade (T), nodal grade (pN), and histology. Because T and pN were important factors for bone metastasis prediction, subgroups were made by pTNM stage. Patients at stages IIIA, IIIB and IV had an incidence of >3% per person-year, patients with stage I <1% per person-year, and those with stages II were between 1 and 3%. Further analysis with histology in stage II patients showed that stage IIB with high risk histology also had a high incidence (3% person year), whereas stage IIA with medium risk histology were <1%.

Conclusions

Bone metastasis incidence remained constant for many years. Using pN, T, and histopathology, patients could be classified into high, medium, and low risk groups.

Use of bisphosphonates and risk of postmenopausal breast cancer

PURPOSE

Bisphosphonates are commonly used for the treatment of osteoporosis and for prevention and treatment of skeletal lesions due to malignancy. However, the association between the use of bisphosphonates and the risk of developing breast cancer has not been reported.

PATIENTS AND METHODS

The Breast Cancer in Northern Israel Study is a population-based case-control study in northern Israel of patients with breast cancer and age-, clinic-, and ethnic-group matched controls. Use of bisphosphonates was assessed in 4,039 postmenopausal patients and controls, members of Clalit Health Services, using pharmacy records.

RESULTS

The use of bisphosphonates for longer than 1 year before diagnosis, but not for shorter than 1 year, was associated with a significantly reduced relative risk of breast cancer (odds ratio [OR], 0.61; 95% CI, 0.50 to 0.76). This association remained significant after adjustment for age, fruit, and vegetable consumption, sports activity, family history of breast cancer, ethnic group, body mass index, use of calcium supplements, hormone replacement therapy use, number of pregnancies, months of breast feeding, and age at first pregnancy (OR, 0.72; 95% CI, 0.57 to 0.90). Breast cancer risk did not change further if bisphosphonates were used for more years. Breast tumors identified in bisphosphonates users were more often estrogen receptor positive and less often poorly differentiated.

CONCLUSION

The use of bisphosphonates for longer than 1 year was associated with a 28% relative reduction in the risk of postmenopausal breast cancer. Tumors developing under bisphosphonates treatment tended to have a favorable prognostic factors profile.

Oral bisphosphonate use and breast cancer incidence in postmenopausal women

PURPOSE

Emerging clinical evidence suggests intravenous bisphosphonates may inhibit breast cancer while oral bisphosphonates have received limited evaluation regarding breast cancer influence.

PATIENTS AND METHODS

The association between oral bisphosphonate use and invasive breast cancer was examined in postmenopausal women enrolled onto the Women's Health Initiative (WHI). We compared a published hip fracture prediction model, which did not incorporate bone mineral density (BMD), with total hip BMD in 10,418 WHI participants who had both determinations. To adjust for potential BMD difference based on bisphosphonate use, the hip fracture prediction score was included in multivariant analyses as a BMD surrogate.

RESULTS

Of the 154,768 participants, 2,816 were oral bisphosphonate users at entry (90% alendronate, 10% etidronate). As calculated hip fracture risk score was significantly associated with both BMD (regression line = 0.79 to 0.0478 log predicted fracture; P < .001; r = 0.43) and breast cancer incidence (P = .03), this variable was incorporated into regression analyses to adjust for BMD difference between users and nonusers of bisphopshonate. After 7.8 mean years of follow-up (standard deviation, 1.7), invasive breast cancer incidence was lower in bisphosphonate users (hazard ratio [HR], 0.68; 95% CI, 0.52 to 0.88; P < .01) as was incidence of estrogen receptor (ER) -positive invasive cancers (HR, 0.70; 95% CI, 0.52 to 0.94, P = .02). A similar but not significant trend was seen for ER-negative invasive cancers. The incidence of ductal carcinoma in situ was higher in bisphosphonate users (HR, 1.58; 95% CI, 1.08 to 2.31; P = .02).

CONCLUSION

Oral bisphosphonate use was associated with significantly lower invasive breast cancer incidence, suggesting bisphosphonates may have inhibiting effects on breast cancer.

[The role of bisphosphonates of adjuvant therapy in breast cancer]

Breast cancer is the most common neoplasm in women. Bone is the most common site of metastatic spread from primary operable breast cancer, causing pain, fractures and hypercalcemia. This spread depends on the release of osteolytic substances by the cancer cells. The osteoclasts also release growth factors that can act back on the cancer cells to activate growth. Biphosphonates, antiosteolytic agents, have been shown to reduce the progression of established bone metastases. Emerging evidence suggests that biphosphonates also have antitumor and antimetastatic properties, including the inhibition of angiogenesis, tumor-cell invasion, and adhesion in bone; the induction of apoptosis; antitumor sinergy with cytotoxic chemotherapy; and immunomodulatory effects through induction of γ/δ T cells. These findings were the background and rationale for ongoing clinical trials, in order to establish their role as a part of adjuvant treatment for early breast cancer. The oral biphosphonate clodronate (1600mg/d) is effective in patients with bone metastases. When used as adjuvant therapy, given to patients with operable breast cancer for two years, clodronate has been reported to reduce the risk of bone metastases during a 2-year study period with a significant reduction in mortality. This benefit supports its use as additional adjuvant therapy for patients with operable breast cancer. Zoledronic acid, a potent nitrogen-containing biphosphonate, has been shown to maintain or increase bone mineral density (BMD) in premenopausal women with early-stage breast cancer receiving adjuvant hormone therapies as well as healthy postmenopausal women with low BMD. Recent large clinical trials with biphosphonates in the (neo)adjuvant setting for early-breast cancer, demonstrate an improvement of disease-free and overall survival as well as increased pathologic rate responses.

Targeting mitochondria for cancer therapy

Several recent insights into the roles of mitochondria in cancer have renewed efforts to develop nongenotoxic therapies targeting mitochondrial proteins and functions. Mitochondria are central hubs for intrinsic apoptotic pathways that are activated by cellular stress and injury, and as a consequence, cancers often have defects in these pathways. Bcl-2, the first identified regulator of apoptotic cell deaths, was discovered as an oncogene in human cancers. BCL-2 inhibits mitochondrial pathways of apoptosis through local effects at mitochondrial and endoplasmic reticulum membranes. Increased expression of BCL-2 and the related antiapoptotic proteins BCL-X(L), MCL-1, and BCL-W occurs in significant subsets of common cancer types (Table I) and is generally correlated with poor response. Although incomplete, the emerging understanding of BCL-2 functions through structural, biochemical, and organelle physiology studies has provided paths for targeting BCL-2 with small molecules. Cancer cells also exhibit metabolic differences with their normal cell counterparts, including aerobic glycolysis, known as the Warburg effect, mitochondrial membrane hyperpolarization, and unusual dependence on nutrient substrates such as glucose and glutamine. This knowledge has prompted reexamination of the potential cancer selectivity of previously identified mitochondriotoxic compounds, including approved drugs for other indications, and screening programs to identify new compounds with mitochondrial activities.

Adjuvant pamidronate therapy prevents the development of bone metastases in breast cancer patients with four or more positive nodes

Bisphosphonates are strongly efficacious in inhibiting osteoclast bone resorption and have beneficial effects on bone metastasis. Due to their mechanism of action, bisphosphonates are expected to prevent the development of bone metastases in breast cancer patients. Pamidronate is a potent inhibitor of osteoclast activity. We examined whether pamidronate was able to prevent the development of bone metastases in breast cancer patients at high risk for bone metastasis. Between 1997 and 2001, 90 patients with primary breast cancer with ≥4 positive nodes were assigned to receive 45 mg pamidronate 4 times every 2 weeks (33 patients) or standard follow-up (57 patients) based on patient self-preference. Patients underwent surgery and adjuvant therapy. The characteristics of the patients in the two groups were well-balanced. The median follow-up period was 5 years. Bone metastases were detected in 12.1% of patients in the pamidronate group and 40.4% in the control group (p=0.005). Distant metastases (36.4 vs. 56.1%, p=0.071) and non-osseous metastases (33.3 vs. 52.6%, p=0.077) were detected at a lower frequency in the pamidronate group. Thus, the rate of bone metastasis-free survival was significantly higher in the pamidronate group (85.9 vs. 64.0% at 5 years, p=0.023). Overall and disease-free survival rates did not differ between the two groups. In the pamidronate group, the incidence of bone metastases was significantly reduced and bone metastasis-free survival was significantly higher. Adjuvant pamidronate therapy therefore prevents the development of bone metastases in breast cancer patients with ≥4 positive nodes.