Improving bone health in patients with early breast cancer by adding bisphosphonates to letrozole: The Z-ZO-E-ZO-FAST program

Validation of CTS5 Model in Large-scale Breast Cancer Population and Combination of CTS5 and Ki-67 Status to Develop a Novel Nomogram for Prognosis Prediction

BACKGROUND

More than half of patients with early-stage estrogen receptor-positive (ER+) breast cancer relapse after completing 5 years of adjuvant endocrine therapy, so it is important to determine which patients are candidates for extended endocrine therapy. The clinical treatment score after 5 years (CTS5) is a prognostic tool developed based on postmenopausal ER+ breast cancer to assess the risk of late distant recurrence (LDR) after 5 years of adjuvant endocrine therapy for breast cancer. We aimed to externally validate the prognostic value of CTS5 in premenopausal and postmenopausal patients and combined with Ki-67 to develop a new model to improve the ability of prognosis prediction.

METHODS

We included a total of 516 patients with early-stage ER+ breast cancer who had received 5 years of adjuvant endocrine therapy and were recurrence-free for 5 years after surgery. According to menopausal status, we divided the study population into 2 groups: premenopausal and postmenopausal women. The CTS5 of each patient was calculated using a previously published formula, and the patients were divided into low, intermediate, and high CTS5 risk groups according to their CTS5 values. Based on the results of the univariate analysis ( P <0.01), a multivariate COX proportional hazards regression analysis was conducted to establish a nomogram with significant variables ( P <0.05). The discriminative power and accuracy of the nomograms were assessed using the concordance index (C-index), calibration curve, and area under the time-dependent receiver operating characteristic curve. Discrimination and calibration were evaluated by bootstrapping 1000 times. Finally, we utilized decision curve analysis to assess the performance of our novel predictive model in comparison to the CTS5 scoring system with regard to their respective benefits and advantages.

RESULTS

The median follow-up time was 7 years (6 to 9 years). The 516 women were categorized by CTS5 as follows: 246(47.7%) low risk, 179(34.7%) intermediate risk, and 91(17.6%) high risk. Using the CTS5 score as a continuous variable, patients' risk score was significantly positively associated with recurrence risk in both premenopausal and postmenopausal subgroups. For HER2- premenopausal patients and HER2+ postmenopausal patients, the CTS5 score was positively correlated with LDR risk. Patients with a Ki-67≥20% had a higher risk of LDR regardless of menopausal status. Using the CTS5 score as a categorical variable, the high-risk group of HER2- premenopausal patients had a higher risk of LDR. However, the CTS5 model could not distinguish the risk of LDR in different risk groups for HER2+ postmenopausal patients. In the high-risk group, patients with Ki-67≥20% had a higher risk of LDR, regardless of menopausal status. We developed a new nomogram model by combining the CTS5 model with Ki-67 levels. The C-indexes premenopausal and postmenopausal cohorts were 0.731 and 0.713, respectively. The nomogram model was well calibrated, and the time-dependent ROC curves indicated good specificity and sensitivity. Furthermore, decision curve analysis demonstrated that the new model had a wider and practical range of threshold probabilities, resulting in an increased net benefit compared with the CTS5 model.

CONCLUSIONS

Our study demonstrated that the CTS5 model can effectively predict the risk of LDR in early-stage ER+ breast cancer patients in both premenopausal and postmenopausal patients. Extended endocrine therapy is recommended for patients with Ki-67≥20% in the CTS5 high-risk group, as well as premenopausal patients with HER2-. Compared with CTS5, the new nomogram model has better identification and calibration capabilities, and further research is required to validate its efficacy in large-scale, multicenter, and prospective studies.

Bone health in breast cancer

Early breast cancer is among the most common cancers worldwide. Recent advances continue to improve outcomes and increase long-term survivorship. However, therapeutic modalities are deleterious for patients' bone health. While antiresorptive therapy may partially negate this, consequent reduction in rates of fragility fractures remains unproven. Selective prescription of bisphosphonates or denosumab may be an amicable middle ground. Recent evidence also suggests a possible role of osteoclast inhibitors as adjuvant therapy, but the evidence is modest at best. In this narrative clinical review, we explore the impact of various adjuvant modalities on bone mineral density and fragility fracture rates of early breast cancer survivors. We also review optimal patient selection for antiresorptive agents, their impact on rates of fragility fractures, and the possible role of these agents as adjuvant therapy.

Breast cancer therapy and bone

Breast cancer is the most common cancer in women and the leading cause of cancer-associated mortality. The estrogen deprivation associated with therapies used to treat this disease may result in significant loss of bone density and a consequent increase in fracture risk. Anti-resorptive osteoporosis therapies (bisphosphonates and the inhibitor of receptor activator of nuclear factor-κB ligand [RANKL] denosumab) play an important role in the mitigation of cancer therapy-induced bone loss (CTIBL), and may function as adjuvant therapy in moderate to high-risk breast cancer to prevent disease recurrence. Various international guidelines have delineated treatment thresholds based on both bone density assessment and clinical risk factors for CTIBL. The role of these bone-targeted therapies as adjuvant anti-cancer treatment is evolving. Currently, evidence supports the use of the bisphosphonates, zoledronic acid and clodronate, in this setting. Unfortunately, a focus on bone health in women with breast cancer is often not prioritized, leaving this group vulnerable to significant bone loss and subsequent fracture.

Validation of CTS5 model in large-scale breast cancer population and the impact of menopausal and HER2 status on its prognostic value

Clinical Treatment Score post-5 years (CTS5) is a promising prognostic tool to evaluate late recurrence risk for breast cancer. Our study aimed to validate its prognostic value in large-scale population and explore the impact of menopausal and HER2 status on CTS5 model. We performed a retrospective cohort study using the Surveillance, Epidemiology, and End Results (SEER) database. Survival analyses were conducted to assess the prognostic value of CTS5 in different breast cancer subgroups in terms of overall survival (OS) and breast cancer specific survival (BCSS) after five years. A total of 23,168 breast cancer patients with positive hormone receptor (HoR) were enrolled. Postmenopausal and premenopausal patients were 13,686 and 9,482, respectively. Taking CTS5 score as a continuous variable, it had significant positive correlation with poor prognosis beyond five years in both postmenopausal and premenopausal subgroups. Nevertheless, for HER2+ postmenopausal patients, the model has less effective prognostic value on long-term BCSS [HR1.177 (95%CI 0.960-1.443), p = 0.117]. Using CTS5 score as a categorical variable, HER2- patients with high-risk level revealed significant poor survival in terms of both BCSS and OS, irrespective of menopausal status. Our study showed the CTS5 model could be a useful prognostic tool for predict long-term survival in HoR+/HER2- patients. And further large-scale studies are warranted to assess its prognostic value for HER2+ patients and develop novel prediction model for late recurrence risk estimation.

Fractures frequently occur in older cancer patients: the MD Anderson Cancer Center experience

PURPOSE AND INTRODUCTION

A growing number of cancer patients are older adults aged 65 years and older. Patients with cancer are at increased risk for developing osteoporosis, falls, and fractures. We sought to identify the incidence of fractures in older adults who underwent cancer care between January 2013 and December 2015.

METHODS

A comprehensive geriatric assessment was performed, and bone densitometry was measured at baseline, with a 2-year follow-up.

RESULTS

In this study, among 304 patients with gastrointestinal, urologic, breast, lung, and gynecologic cancers we evaluated, and who completed the bone density testing (n = 199), 80% had osteoporosis or low bone mass (osteopenia). There was a higher prevalence of osteoporosis in cancer patients (40 vs. 16%, p = 0.05) than in population studies. Vitamin D insufficiency (< 30 ng/ml) was identified in 49% of tested cases (n = 245). Risk factors for low bone mass or osteoporosis were advanced age (p = 0.05), malnutrition (p = 0.04), and frailty (p = 0.01). Over the following 2 years (median follow-up 18 months), there was an incidence of fractures of 110 per 1000 person-years, or 2.8 times higher than reported in individuals without cancer. Risk factors for fractures included advanced age (70-79 vs. 60-69 years, p = 0.05) and frailty (p = 0.03).

CONCLUSION

Most older cancer patients studied have osteoporosis or low bone mass, resulting in an almost 3-fold increase in fracture risk as compared to epidemiologic studies. Bone health issues are commonly seen in older cancer patients, we recommend universal bone density testing. The initiation of antiresorptive treatment when findings are of osteopenia or osteoporosis will reduce the risk of fractures.

Therapeutic Bone-Modifying Agents in the Nonmetastatic Breast Cancer Setting: The Controversy and a Value Assessment

Clinical trials and meta-analyses investigating bisphosphonates as an adjuvant breast cancer therapy have shown a consistent trend, with postmenopausal women and women receiving ovarian suppression with gonadotropin-releasing hormone therapy gaining improved breast cancer outcomes with the use of adjuvant bisphosphonate therapy. The interpretation of these data is controversial, because the primary endpoints of the majority of adjuvant bisphosphonate studies have been negative. Pros and cons as well as the value of adjuvant bisphosphonate therapy are discussed here.

Managing Aromatase Inhibitor-Associated Bone Loss in Breast Cancer

Although the incidence of breast cancer has increased, there is a concurrent decrease in the death rate, and the outlook for women with early-stage breast cancer remains positive. The current 5-year survival rate of women diagnosed with breast cancer is nearly 90%, due, in part, to the use of effective adjuvant therapies that often include aromatase inhibitors. However, long-term treatment with these therapies is known to have adverse effects on bone metabolism, leading to bone loss. Bone loss during adjuvant endocrine therapy may be higher than that observed during menopause and may require more potent therapy. Although there are approved treatments for osteolytic bone lesions from bone metastases, there is no approved therapy for bone loss associated with adjuvant cancer therapy. Bisphosphonates have demonstrated promising results in this setting, and zoledronic acid is currently under consideration by the US FDA and Europe (EMEA) for the treatment of aromatase inhibitor-associated bone loss.

Women commencing anastrozole, letrozole or tamoxifen for early breast cancer: the impact of comorbidity and demographics on initial choice

Background

Australian clinical guidelines recommend endocrine therapy for all women with hormone-dependent early breast cancer. Guidelines specify tamoxifen as first-line therapy for pre-menopausal women, and tamoxifen or an aromatase inhibitor (AI) for post-menopausal women depending on the risk of recurrence based on tumour characteristics including size. Therapies have different side effect profiles; therefore comorbidity may also influence choice. We examined comorbidity, and the clinical and demographic characteristics of women commencing different therapies.

Patients and Methods

We identified the first dispensing of tamoxifen, anastrozole or letrozole for women diagnosed with invasive breast cancer in the 45 and Up Study from 2004–2009 (N = 1266). Unit-level pharmacy and medical service claims, hospital, Cancer Registry, and self-reported data were linked to determine menopause status at diagnosis, tumour size, age, comorbidities, and change in subsidy restrictions. Chi-square tests and generalised regression models were used to compare the characteristics of women commencing different therapies.

Results

Most pre-menopausal women commenced therapy with tamoxifen (91%). Anastrozole was the predominant therapy for post-menopausal women (57%), followed by tamoxifen (28%). Women with osteoporosis were less likely to commence anastrozole compared with tamoxifen (anastrozole RR = 0.7, 95% CI = 0.5–0.9). Women with arthritis were 1.6-times more likely to commence letrozole than anastrozole (95% CI = 1.1–2.1). Tamoxifen was more often initiated in women with tumours >1 cm, who were also ≥75 years. Subsidy restriction changes were associated with substantial increases in the proportion of women commencing AIs (anastrozole RR = 4.3, letrozole RR = 8.3).

Conclusions

The findings indicate interplay of comorbidity and therapy choice for women with invasive breast cancer. Most post-menopausal women commenced therapy with anastrozole; however, letrozole and tamoxifen were more often initiated for women with comorbid arthritis and osteoporosis, respectively. Tamoxifen was also more common for women with tumours >1 cm and aged ≥75 years. Subsidy restrictions appear to have strongly influenced therapy choice.

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.

Perspectives in the elderly patient: benefits and limits of bisphosphonates and denosumab

Skeletal metastases affect a large percentage of the cancer population and contribute to a marked decrease in their quality of life and survival, in particular in elderly population. A future end-point of bone-protecting therapy is the demonstration of its ability to prevent or improve results in the treatment of metastatic disease, enlarging their clinical indications in metastatic and osteoporotic setting with different schedules. In this chapter we will discuss on pharmacokinetic and pharmacodynamic interactions of bisphosphonates in elderly, and the preclinical and clinical evidences of anticancer activity of bone-targeted therapies will be critically described. The clinical results of new targeted therapies (such as rank/rankl/OPG inhibition) will be reported both in bone metastatic and in adjuvant settings. Finally, the prevention of cancer treatment-induced bone loss (CTIBL) represents both in young and more in old patients an emerging issue in the bone health care. For this reason, this chapter will discuss the results of current therapies in this clinical setting.

Bone mineral density in breast cancer patients treated with adjuvant letrozole, tamoxifen, or sequences of letrozole and tamoxifen in the BIG 1-98 study (SAKK 21/07)

BACKGROUND

The risk of osteoporosis and fracture influences the selection of adjuvant endocrine therapy. We analyzed bone mineral density (BMD) in Swiss patients of the Breast International Group (BIG) 1-98 trial [treatment arms: A, tamoxifen (T) for 5 years; B, letrozole (L) for 5 years; C, 2 years of T followed by 3 years of L; D, 2 years of L followed by 3 years of T].

PATIENTS AND METHODS

Dual-energy X-ray absorptiometry (DXA) results were retrospectively collected. Patients without DXA served as control group. Repeated measures models using covariance structures allowing for different times between DXA were used to estimate changes in BMD. Prospectively defined covariates were considered as fixed effects in the multivariable models.

RESULTS

Two hundred and sixty-one of 546 patients had one or more DXA with 577 lumbar and 550 hip measurements. Weight, height, prior hormone replacement therapy, and hysterectomy were positively correlated with BMD; the correlation was negative for letrozole arms (B/C/D versus A), known osteoporosis, time on trial, age, chemotherapy, and smoking. Treatment did not influence the occurrence of osteoporosis (T score < -2.5 standard deviation).

CONCLUSIONS

All aromatase inhibitor regimens reduced BMD. The sequential schedules were as detrimental for bone density as L monotherapy.

Adverse bone effects during pharmacological breast cancer therapy

The improved survival and cure rate of breast cancer patients leads to increased diagnosis of later occurring side effects to therapy such as osteoporosis. Conventional chemotherapies such as CMF and CEF are known to induce premature menopause, which increases bone loss but these therapies have additional detrimental effects on bone. The loss in bone mass during chemotherapy is substantial and may lead to increased fracture risk. The influence of taxanes on bone is less well known. Whereas tamoxifen has a slight protective effect on bone loss the opposite is true for aromatase inhibitors. Adverse effect reportings show, that adjuvant treatment with aromatase inhibitors in postmenopausal women increases the risk of clinical fractures as compared to tamoxifen. The Danish Bone Society suggests that all women with operable breast cancer have their fracture risk evaluated including a BMD measurement prior to initiation of adjuvant aromatase inhibitor therapy as a part of the standard examination program. If osteoporosis is diagnosed, anti-osteoporosis therapies should be considered. Moreover, all women undergoing adjuvant chemotherapy and endocrine therapy should be informed of the risk of bone loss and should receive life style advice of how to preserve bone. Adjuvant regimens in breast cancer patients improve survival and cure rates. Therefore it is preferable to use such therapies although they increase risk of side effects such as osteoporosis.

Cancer treatment-induced bone loss: pathophysiology and clinical perspectives

Hormone-ablative therapies for breast or prostate cancer can cause marked and rapid reductions in circulating estrogen or testosterone levels, resulting in significant effects on bone metabolism and cancer treatment-induced bone loss (CTIBL). Most patients with cancer are over the age of 65 and are already at risk for osteoporosis. Thus, accelerated bone loss from CTIBL is especially concerning in this population. Although there are currently no approved therapies for the treatment or prevention of CTIBL, oral bisphosphonates have been used in settings other than oncology to treat bone loss. New-generation i.v. bisphosphonates have demonstrated promising activity in preventing CTIBL in patients receiving hormonal therapy for breast or prostate cancer. In particular, zoledronic acid not only prevents CTIBL in both breast and prostate cancer patients but also increases bone mineral density above baseline. Such agents have the potential to delay or prevent CTIBL in patients receiving hormonal therapies.

Early breast cancer in the elderly: assessment and management considerations

Breast cancer is a common tumour in the elderly and management of early disease in particular is a major challenge for oncologists and geriatricians alike. The process should begin with the Comprehensive Geriatric Assessment (CGA), which should be undertaken before any decisions about treatment are made. The important role of co-morbidities and their effect on life expectancy also need to be taken into account when making treatment decisions. The primary treatments for early breast cancer are surgery, adjuvant radiotherapy and adjuvant systemic therapy. Unfortunately, lack of a specific literature relating to early breast cancer in the elderly means formulating an evidence-based approach to treatment in this context is difficult. We have developed a new approach based on the CGA and comprehensive oncological assessment. This approach facilitates the development of an individualized oncogeriatric care plan and follow-up based on several considerations: the average patient's life expectancy at a given age; the patient's co-morbidities, level of dependence, and the impact of these considerations on diagnostic and therapeutic options as well as life expectancy; and the potential benefit-risk balance of treatment. In the elderly patient with breast cancer, the standard primary therapy is surgical resection (mastectomy or breast-conserving therapy). While node dissection is a major component of staging and local control of breast cancer, no data are available to guide decision-making in women aged >70 years. Primary endocrine therapy (tamoxifen) should be offered to elderly women with estrogen receptor (ER)-positive breast cancer only if they are unfit for or refuse surgery. Trials are needed to evaluate the clinical effectiveness of aromatase inhibitors as primary therapy for infirm older patients with ER-positive tumours. Breast irradiation should be recommended to older women with a life expectancy >5 years, particularly those with large tumours, positive lymph nodes or negative hormone receptors. Adjuvant hormone therapy remains a reasonable therapeutic option in elderly women with positive hormone receptor tumours. Aromatase inhibitors have demonstrated a better toxicity profile and effectiveness as adjuvant therapy than tamoxifen in young postmenopausal women but have not been specifically studied in the elderly population. The efficacy of adjuvant chemotherapy for breast cancer has been established by meta-analysis and numerous randomized trials but, again, women aged > or = 70 years have rarely been included in such trials. At present, it is difficult to provide a validated recommendation for use of adjuvant chemotherapy in elderly patients with breast cancer. There are no follow-up recommendations specifically for elderly patients after treatment of early breast cancer. However, American Society of Clinical Oncology breast cancer surveillance guidelines suggest physician office visits every 3-6 months for 3 years, followed by visits every 6-12 months for 2 years, then annually. Women taking aromatase inhibitors should also undergo bone mineral density measurement every 2 years. The new approach to assessment and management of early breast cancer in the elderly outlined in this article should be considered an intermediate step because additional evidence to support clinical practice is still needed. Bearing this in mind, physicians should encourage enrollment of elderly breast cancer patients in clinical trials.

Effect of Anastrozole on Bone Mineral Density: 5-Year Results From the Anastrozole, Tamoxifen, Alone or in Combination Trial 18233230

Purpose

The Arimidex, Tamoxifen, Alone or in Combination (ATAC) trial (median follow-up, 68 months) has shown that adjuvant anastrozole has superior efficacy and better tolerability than tamoxifen. However, anastrozole reduces circulating estrogen, and low estradiol levels are associated with decreased bone mineral density (BMD) and increased fracture risk. It is therefore important to understand the effects of long-term aromatase inhibitor therapy on BMD.

Patients and Methods

This prospective substudy of the ATAC trial assessed BMD changes in postmenopausal women with invasive primary breast cancer receiving anastrozole (1 mg/d) or tamoxifen (20 mg/d) as adjuvant therapy for 5 years. Lumbar spine and total hip BMD were assessed at baseline and after 1, 2, and 5 years.

Results

One hundred ninety-seven women from the monotherapy arms of the ATAC trial were recruited onto the bone substudy, and 108 were included in the primary analysis. Among anastrozole-treated patients, there was a decrease in median BMD from baseline to 5 years in lumbar spine (−6.08%) and total hip (−7.24%) compared with the tamoxifen group (lumbar spine, +2.77%; total hip, +0.74%). No patients with normal BMD at baseline became osteoporotic at 5 years.

Conclusion

Anastrozole is associated with accelerated bone loss over the 5-year treatment period. However, although patients with pre-existing osteopenia are likely to require monitoring and bone-protection strategies, patients with normal BMD would not appear to require monitoring beyond the recommendation for healthy postmenopausal women. The effect of anastrozole on bone should be weighed against its superior efficacy and better tolerability profile versus tamoxifen in the main ATAC trial.

Management of breast cancer in elderly individuals: recommendations of the International Society of Geriatric Oncology

Breast cancer is the most commonly diagnosed cancer and the leading cause of cancer mortality in women worldwide. Elderly individuals make up a large part of the breast cancer population, and there are important specific considerations for this population. The International Society of Geriatric Oncology created a task force to assess the available evidence on breast cancer in elderly individuals, and to provide evidence-based recommendations for the diagnosis and treatment of breast cancer in such individuals. A review of the published work was done with the results of a search on Medline for English-language articles published between 1990 and 2007 and of abstracts from key international conferences. Recommendations are given on the topics of screening, surgery, radiotherapy, (neo)adjuvant hormone treatment and chemotherapy, and metastatic disease. Since large randomised trials in elderly patients with breast cancer are scarce, there is little level I evidence for the treatment of such patients. The available evidence was reviewed and synthesised to provide consensus recommendations regarding the care of breast cancer in older adults.

New developments of aminobisphosphonates: the double face of Janus

BACKGROUND

Bisphosphonate (BP) therapy has become a standard of therapy for patients with malignant bone disease. In vivo preclinical and preliminary clinical data indicate that BPs may prevent cancer treatment-induced bone loss and the onset of malignant bone disease in patients with early-stage cancer.

DESIGN

This review will describe the preclinical evidences of action of BPs on osteoclasts and tumor cells. In addition, the effects of principal BPs on skeletal disease progression in patients with breast cancer, prostate cancer, non-small-cell lung cancer and other cancers will be reported. The preliminary clinical data from retrospective trials on the effect of zoledronic acid (ZA) on survival will be described and the ongoing adjuvant phase III trial will be analyzed.

CONCLUSIONS

This review will describe the preliminary clinical evidences from prospective studies on the effect of ZA treatment on the prevention of bone metastasis.

Aromatase inhibitor and bone

Aromatase is a key enzyme of intratumoral production of estrogen in breast cancers. Aromatase inhibitors are commonly used as hormone therapy in postmenopausal estrogen sensitive breast cancer patients. Type I aromatase inhibitors such as exemestane are steroidal inhibitors, which have androstenedione like structure and bind to androgen receptor with low affinity. Type II aromatase inhibitors such as anastrozole and letrozole are known as non-steroidal inhibitors, which are non-competitive inhibitors of aromatase. Sex steroid hormones such as estrogen and androgen play important roles in the maintenances of female and male bone tissues. It is well known that adult women have less bone mass than men. Especially after menopause, adult women loss their bone mass more rapidly than men of comparable age do. Therefore, many clinical reports of breast cancer patients treated with aromatase inhibitors have emphasized potential bone loss caused by aromatase inhibition. Several basic researches using animal model or in vitro model demonstrated the different effects of steroid and non-steroid aromatase inhibitors on bone tissues and cells. In this review, we summarize the effects of AIs on bone tissues reported in clinical studies and animal/in vitro studies.

The use of bisphosphonates in cancer patients

Skeletal-related events resulting from bone metastases or osteoporosis can significantly contribute to morbidity and mortality in cancer patients. Expert opinion on the effectiveness of bisphosphonates in this setting is evolving. Here we review current evidence on the risks and benefits of bisphosphonate therapy for a wide variety of cancers, as well as clinical management of its adverse effects. A MEDLINE search of English-language literature (1966 through May 2006) was conducted using the terms bisphosphonate, cancer, multiple myeloma, malignancy, and randomized controlled clinical studies. Studies were selected based on clinical pertinence, with an emphasis on phase III clinical trials. We reviewed bibliographies for other relevant articles. Accumulating evidence reveals that bisphosphonate therapy has a significant effect in preventing skeletal complications in multiple myeloma, breast cancers, and prostate cancer, and in reducing skeletal complications in other metastatic bone malignancies. Emerging data indicate that bisphosphonates are useful for preventing bone loss resulting from cancer or its therapy. The efficacy of bisphosphonates for early-stage breast cancers remains controversial. Significant risks of bisphosphonate therapy include nephrotoxicity, electrolyte abnormalities, and osteonecrosis of the jaw. Bisphosphonate therapy has a clear role in the management of skeletal metastases associated with a variety of cancers. However, significant side effects require ongoing monitoring and treatment.

Endocrine therapy for breast cancer: an overview

Endocrine therapy for breast cancer has been established in the adjuvant treatment for primary disease and in the treatment of advanced disease. The ER remains the best predictor of response although other factors exist and need to be identified. Pharmacological manipulation has been replacing ablative procedures. Tamoxifen used to be the most popular agent of choice and promising new agents include the pure anti-oestrogens and the third generation selective aromatase inhibitors. Ongoing and future studies will optimise treatment in established areas and will exploit its potential roles in preoperative use and chemoprevention.

Optimal management of metastatic bone disease

OBJECTIVES

Skeletal-related events (SREs) from bone metastases are a major cause of morbidity and significantly decrease patients' quality of life. Strategies for the optimal management of SREs with bisphosphonates are explored.

METHODS

Existing and novel therapies were identified and published guidelines were reviewed through PubMed key word searches.

RESULTS

Nitrogen-containing bisphosphonates effectively reduce the risk of SREs in patients with bone metastases from a variety of solid tumors and bone lesions from multiple myeloma. Review of placebo-controlled trials in breast cancer patients with bone metastases indicated that zoledronic acid produced the greatest SRE risk reduction of all bisphosphonates evaluated. Zoledronic acid has demonstrated significant long-term benefits for prevention of SREs and palliative effects for bone pain. Zoledronic acid also improves quality of life. Analysis of recent trials indicates that early zoledronic acid intervention provides greater benefit in asymptomatic patients.

CONCLUSIONS

Patients with malignant bone disease are at a continuous risk for SREs, and bisphosphonates reduce the incidence and delay the onset of SREs. Zoledronic acid has demonstrated the greatest SRE risk reduction of all bisphosphonates and significantly improves pain scores in patients with breast cancer. Zoledronic acid is the only bisphosphonate to show efficacy in prostate cancer, lung cancer, and other solid tumors.