Changes in bone turnover and in bone mass in women with breast cancer switched from tamoxifen to exemestane

Bone mineral density, osteopenia and osteoporosis among US adults with cancer

BACKGROUND

Bone mineral deficits are one of the most common complications in cancer survivors. However, there are no studies evaluating bone mineral density (BMD) and the prevalence of osteopenia and osteoporosis among patients with different types of cancers.

AIM

The objective was to assess BMD and evaluate the prevalence of osteopenia and osteoporosis among US adults with cancer.

DESIGN

A cross-section propensity score matching study.

METHODS

We extracted data from National Health and Nutrition Examination Survey database from 2005 to 2018. We compared BMD in participants with and without cancer which was further analyzed according to cancer type. We conducted logistic regression to evaluate adjusted odds ratios of osteopenia and osteoporosis and determine risk factors for their development.

RESULTS

We found that BMD was significantly higher in participants without cancer than cancer patients. Furthermore, the median BMD of patients with breast cancer or skin cancer (including melanoma) was significantly lower than participants without cancer. People with breast, lung, genitourinary and skin cancers were more likely to incur osteopenia/osteoporosis than those without cancer.

CONCLUSIONS

BMD differs depending upon type in survivors. Individuals with a history of cancer have a poor understanding of osteoporosis and its risk factors. Understanding risk factors in patients with cancers identified in our study may be helpful for preventing osteoporosis and fractures and the development of screening guidelines.

The effect of denosumab in breast cancer patients receiving adjuvant aromatase inhibitors: 36-month results

INTRODUCTION

Aromatase inhibitor (AI)-associated bone loss increases the risk of bone fracture and reduces patients' quality of life, making it a critical issue worldwide. We conducted a prospective non-randomized clinical trial (UMIN-CTR, UMIN 000016173) to assess the effect of denosumab on bone loss in patients treated with adjuvant AI and have previously reported the results at 12 and 24 months. This study aimed to present the results at 36 months of treatment with denosumab for osteopenia in breast cancer patients who were undergoing treatment with adjuvant AI; 36 months is the longest denosumab treatment period reported so far.

MATERIALS AND METHODS

Patients received 60-mg denosumab subcutaneously every 6 months. Daily supplements containing 500-mg elemental calcium and at least 400 international units of vitamin D were highly recommended throughout the study period. The levels of bone mineral density (BMD) and bone turnover markers, serum tartrate-resistant acid phosphatase isoform 5b, and bone alkaline phosphatase were determined at baseline and 6, 12, 18, 24, and 36 months.

RESULTS

At 36 months, the bone mineral density of the lumbar spine, right femoral neck, and left femoral neck were found to increase by 8.8% (95% confidence interval CI 7.6-10.1), 4.3% (95% CI 3.0-5.5), and 3.1% (95% CI 2.1-4.1), respectively. No non-traumatic clinical fractures occurred in patients receiving AI and denosumab.

CONCLUSION

Twice-yearly administration of denosumab to the breast cancer patients treated with adjuvant AI, regardless of the skeletal site, resulted in consistent increases in BMD without severe adverse events at 36 months.

Bone health care in women with breast cancer

The aim of this article is to analyze and critically appraise the literature regarding optimal bone health care in women with breast cancer and, more specifically, to present (1) the causes of bone loss in breast cancer patients, (2) the appropriate screening for osteoporosis and fracture risk estimation, (3) optimal prevention and therapeutic strategies for osteoporosis and fractures, (4) the role of antiresorptive agents as adjuvant therapy for the prevention of bone metastases and increase of overall survival, and (5) current data on the possible use of menopausal hormone therapy (MHT) in these patients. The objective is to provide a sound pathophysiological background along with evidence-based and practical recommendations for physicians managing such women.

French recommendations on strategies for preventing and treating osteoporosis induced by adjuvant breast cancer therapies

Standard adjuvant therapies for breast cancer such as chemotherapy or aromatase inhibitor and LH-RH agonist hormone therapy are associated with significant survival gains but also induce bone loss by aggravating the estrogen deprivation. The bone loss may be substantial, notably during early treatment, and occurs regardless of the baseline bone mineral density values. The objective of developing these recommendations was to achieve a practical consensus among various scientific societies, based on literature review, about osteoporosis prevention and treatment in these patients. The following scientific societies contributed to the work: Société Française de Rhumatologie (SFR), Groupe de Recherche et d'Information sur les Ostéoporoses (GRIO), Groupe Européen d'Etudes des Métastases Osseuses (GEMO), Association Francophone pour les Soins Oncologiques de Support (AFSOS), Société Française de Sénologie et de Pathologie Mammaire (SFSPM), Société Française de Radiothérapie Oncologique (SFRO). Drug prescription and reimbursement modalities in France were taken into account. These recommendations apply to postmenopausal women taking systemic chemotherapy and/or aromatase inhibitor therapy, non-postmenopausal women taking LH-RH agonist therapy, and non-postmenopausal women with persistent amenorrhea 1 year after chemotherapy completion. All women in these three categories should undergo an evaluation of bone health and receive interventions to combat risk factors for bone loss. Patients with a history of severe osteoporotic fracture and/or a T-score value <-2.5 should receive osteoporosis drug therapy. The FRAX® score should be used to guide treatment decisions in patients whose T-score is between -1 and -2.5. General osteoporosis prevention measures should be applied in patients without criteria for osteoporosis drug therapy, who should undergo bone mineral density measurements 18-24 months later if the baseline T-score is<-1 and 3-5 years later if the baseline T-score is>-1. The anti-tumor effect of bisphosphonates and denosumab was not considered when establishing these recommendations.

Postmenopausal Breast Cancer, Aromatase Inhibitors, and Bone Health: What the Surgeon Should Know

Breast cancer, as the most common malignancy in women, remains a major public health issue despite countless advances across decades. Endocrine therapy is the cornerstone of treatment of the hormone-sensitive subtype of breast cancer. The use of aromatase inhibitors (AIs) in the postmenopausal women has extended the survival beyond that of Tamoxifen, but harbors a subset of side effects, most notably accelerated bone loss. This, however, does not occur in all women undergoing treatment. It is vital to identify susceptible patients early, to limit such events, employ early treatment thereof, or alter drug therapy. International trials on AIs, predominantly performed in North American and European females, provide little information on what to expect in women in developing countries. Here, surgeons often prescribe and manage endocrine therapy. The prescribing surgeon should be aware of the adverse effect of the endocrine therapy and be able to attend to side effects. This review highlights clinical and biochemical factors associated with decrease in bone mineral density in an, as yet, unidentified subgroup of postmenopausal women. In the era of personalized medical care, appropriate management of bone health by surgeons based on these factors becomes increasingly important.

Use of CTX-I and PINP as bone turnover markers: National Bone Health Alliance recommendations to standardize sample handling and patient preparation to reduce pre-analytical variability

The National Bone Health Alliance (NBHA) recommends standardized sample handling and patient preparation for C-terminal telopeptide of type I collagen (CTX-I) and N-terminal propeptide of type I procollagen (PINP) measurements to reduce pre-analytical variability. Controllable and uncontrollable patient-related factors are reviewed to facilitate interpretation and minimize pre-analytical variability.

INTRODUCTION

The IOF and the International Federation of Clinical Chemistry (IFCC) Bone Marker Standards Working Group have identified PINP and CTX-I in blood to be the reference markers of bone turnover for the fracture risk prediction and monitoring of osteoporosis treatment. Although used in clinical research for many years, bone turnover markers (BTM) have not been widely adopted in clinical practice primarily due to their poor within-subject and between-lab reproducibility. The NBHA Bone Turnover Marker Project team aim to reduce pre-analytical variability of CTX-I and PINP measurements through standardized sample handling and patient preparation.

METHODS

Recommendations for sample handling and patient preparations were made based on review of available publications and pragmatic considerations to reduce pre-analytical variability. Controllable and un-controllable patient-related factors were reviewed to facilitate interpretation and sample collection.

RESULTS

Samples for CTX-I must be collected consistently in the morning hours in the fasted state. EDTA plasma is preferred for CTX-I for its greater sample stability. Sample collection conditions for PINP are less critical as PINP has minimal circadian variability and is not affected by food intake. Sample stability limits should be observed. The uncontrollable aspects (age, sex, pregnancy, immobility, recent fracture, co-morbidities, anti-osteoporotic drugs, other medications) should be considered in BTM interpretation.

CONCLUSION

Adopting standardized sample handling and patient preparation procedures will significantly reduce controllable pre-analytical variability. The successful adoption of such recommendations necessitates the close collaboration of various stakeholders at the global stage, including the laboratories, the medical community, the reagent manufacturers and the regulatory agencies.

Antineoplastic treatment effect on bone mineral density in Mexican breast cancer patients

BACKGROUND

Breast cancer is the most deadly malignancy in Mexican women. Although treatment has improved, it may significantly affect bone mineral status in those who receive it. The aim of this study was to assess the impact of cancer treatment on bone mineral density (BMD) and bone mineral content (BMC), in patients with breast cancer and explore the interaction of menopausal status and clinical stage with cancer treatment on such changes.

METHODS

A quasi-experimental design was applied with measurements before and after a chemotherapy treatment in 40 patients with primary diagnosis of invasive breast cancer. BMD and body composition measurements were taken by dual X-ray absorptiometry (DXA) and changes in these variables due to therapy were analyzed using mixed regression for repeated measurements.

RESULTS

Significant loss was found in femoral neck and L2-L4 BMD (p < 0.001). Patients diagnosed with osteopenia or osteoporosis received calcium + vitamin D supplementation (600 mg/200 IU day). It showed a protective effect in the decrease of femoral neck BMD and total BMC. BMD loss in both femoral neck and L2-L4 BMD was higher in premenopausal women: 0.023 g/cm² in femoral neck and 0.063 g/cm² in L2-L4 (p < 0.001), while in postmenopausal women BMD loss was 0.015 g/cm² in femoral neck and 0.035 g/cm² in L2-L4 (p = 0.021 and p = 0.001 respectively). Change in lumbar spine BMD was prominent in premenopausal women with advanced clinical stage (IIB, IIIA, IIIB): 0.066 g/cm² (p = 0.003).

CONCLUSION

The antineoplastic breast cancer treatment with chemotherapy had a negative impact on BMD, in premenopausal women overall, although a differential effect was found according to clinical stage and calcium supplementation status.

Assessing the prevalence of compromised bone health among overweight and obese African-American breast cancer survivors: a case-control study

PURPOSE

Osteoporosis increases the risk of fracture and is often considered a late effect of breast cancer treatment. We examined the prevalence of compromised bone health in a sample of exclusively African-American (AA) breast cancer survivors since bone mineral density (BMD) varies by race/ethnicity in healthy populations.

METHODS

Using a case-control design, AA women in a weight loss intervention previously diagnosed and treated for stages I-IIIa breast cancer were matched 1:1 on age, race, sex, and BMI with non-cancer population controls (n = 101 pairs) from National Health and Nutrition Examination Survey (NHANES). Questionnaires and dual-energy x-ray absorptiometry (DXA) scanning were completed, and participants were categorized as having normal bone density, low bone mass, or osteoporosis using the World Health Organization (WHO) definition for femoral neck T-scores.

RESULTS

The majority of these overweight/obese survivors were 6.6 (±4.7) years post-diagnosis, had stage II (n = 46) or stage III (n = 16) disease, and treated with chemotherapy (76 %), radiation (72 %), and/or adjuvant hormone therapies (45 %). Mean femoral neck BMD was significantly lower in cases vs. matched non-cancer population controls (0.85 ± 0.15 vs. 0.91 ± 0.14 g/cm(2), respectively; p = 0.007). However, the prevalence of low bone mass and osteoporosis was low and did not significantly differ between groups (n = 101 pairs; p = 0.26), even when restricted to those on adjuvant hormone therapies (n = 45 pairs; p = 0.75). Using conditional logistic regression, controlling for dietary factors and education, the odds of developing compromised bone health in AA breast cancer survivors was insignificant (OR 1.5, 95 % CI 0.52, 5.56).

CONCLUSIONS

These null case-control findings challenge the clinical assumption that osteoporosis is highly prevalent among all breast cancer survivors, providing foundational evidence to support differences by race/ethnicity and body weight.

IMPLICATIONS FOR CANCER SURVIVORS

Routine bone density testing and regular patient-provider dialogue is critical in overweight/obese AA breast cancer survivors to ensure that healthy lifestyle factors (e.g., ideal weight, regular weight-bearing exercises, dietary adequacy of calcium and vitamin D) support optimal skeletal health.

Bone mineral density and circulating biomarkers in the BIG 1-98 trial comparing adjuvant letrozole, tamoxifen and their sequences

The purpose of the study is to determine the effects of the BIG 1-98 treatments on bone mineral density. BIG 1-98 compared 5-year adjuvant hormone therapy in postmenopausal women allocated to four groups: tamoxifen (T); letrozole (L); 2-years T, 3-years L (TL); and 2-years L, 3-years T (LT). Bone mineral density T-score was measured prospectively annually by dual energy X-ray absorption in 424 patients enrolled in a sub-study after 3 (n = 150), 4 (n = 200), and 5 years (n = 74) from randomization, and 1 year after treatment cessation. Prevalence of osteoporosis and the association of C-telopeptide, osteocalcin, and bone alkaline phosphatase with T-scores were assessed. At 3 years, T had the highest and TL the lowest T-score. All arms except for LT showed a decline up to 5 years, with TL exhibiting the greatest. At 5 years, there were significant differences on lumbar T-score only between T and TL, whereas for femur T-score, differences were significant for T versus L or TL, and L versus LT. The 5-year prevalence of spine and femur osteoporosis was the highest on TL (14.5 %, 7.1 %) then L (4.3 %, 5.1 %), LT (4.2 %, 1.4 %) and T (4 %, 0). C-telopeptide and osteocalcin were significantly associated with T-scores. While adjuvant L increases bone mineral density loss compared with T, the sequence LT has an acceptable bone safety profile. C-telopeptide and osteocalcin are useful markers of bone density that may be used to monitor bone health during treatment. The sequence LT may be a valid treatment option in patients with low and intermediate risk of recurrence.

Aromatase inhibitors in the breast cancer clinic: focus on exemestane

Breast cancer is the most prevalent type of cancer in women and responsible for significant female cancer-related mortality worldwide. In the Western world, over 80% of breast cancers are hormone-receptor positive for which endocrine therapy is administered. The main anti-estrogen treatments in use consist of selective estrogen-receptor modulators, such as tamoxifen, and third-generation aromatase inhibitors (AIs), such as exemestane, letrozole, and anastrozole. In this review, the focus will lie on exemestane, its clinical use, and its side-effect profile. Exemestane is the only third-generation steroidal AI. Its efficacy as a first-line treatment in metastatic breast cancer has been demonstrated. Therefore, exemestane could be considered a valid first-line therapeutic option, but it also can be used in second-line or further situations. Exemestane is mostly used as part of sequential adjuvant treatment following tamoxifen, but in this setting it is also active in monotherapy. Furthermore, this AI has been studied in the neoadjuvant setting as presurgical treatment, and even as chemoprevention in high-risk healthy postmenopausal women. It may reverse side effects of tamoxifen, such as endometrial changes and thromboembolic disease but may also cause some inconvenient side effects itself. Additionally, there is a lack of total cross-resistance between exemestane and nonsteroidal AIs as far as their anti-tumoral efficacy is concerned; moreover the two classes of AIs display a nontotal overlapping toxicity profile. Taking together, exemestane can be considered as a useful treatment option at all stages of breast cancer.

Long-term efficacy and safety of exemestane in the treatment of breast cancer

Exemestane, a steroidal aromatase inhibitor, is licensed for postmenopausal patients with estrogen receptor (ER)-positive breast cancer as second-line therapy in metastatic disease following antiestrogen failure and as part of sequential adjuvant therapy following initial tamoxifen. This study is a systematic literature review, evaluating exemestane in different clinical settings. The Ovid Medline (1948-2012), Embase (1980-2012), and Web of Science (1899-2012) databases were searched. Forty-two relevant articles covering randomized controlled trials were reviewed for efficacy and safety, and three for adherence. With regard to efficacy in metastatic disease, exemestane is superior to megestrol acetate after progression on tamoxifen. There is evidence for noninferiority to fulvestrant (following a prior aromatase inhibitor) and to nonsteroidal aromatase inhibitors in the first-line setting. Combined use with everolimus is shown to be more efficacious than exemestane alone following previous aromatase inhibitor use. In the adjuvant setting, a switch to exemestane after 2-3 years of tamoxifen is superior to 5 years of tamoxifen. Exemestane is noninferior to 5 years of tamoxifen as upfront therapy, and may have a role as an extended adjuvant therapy. Used as neoadjuvant therapy, increased breast conservation is achievable. As chemoprevention, exemestane significantly reduces the incidence of breast cancer in "at-risk" postmenopausal women. Exemestane is associated with myalgias and arthralgias, as well as reduced bone mineral density and increased risk of fracture, which do not appear to persist at follow-up, with subsequent return to pretreatment values. Compared with tamoxifen, there is a reduced incidence of endometrial changes, thromboembolic events, and hot flashes. Limited evidence shows nonadherence in 23%-32% of patients. Evidence is growing in support of exemestane in all clinical settings. It is generally more efficacious and has a better safety profile than tamoxifen. How it compares with the nonsteroidal aromatase inhibitors remains to be established. Further studies are required on adherence to ensure that maximum benefit is obtained.

Systematic review of bone health in older women treated with aromatase inhibitors for early-stage breast cancer

OBJECTIVES

To review data from randomized controlled trials (RCTs) that evaluate adverse bone outcomes in older women using aromatase inhibitors (AIs) for early-stage hormone receptor-positive breast cancer.

DESIGN

Systematic review.

SETTING

International RCTs referenced in Medline and EMBASE databases through August 1, 2011.

PARTICIPANTS

Postmenopausal women with early-stage hormone receptor-positive breast cancer receiving adjuvant endocrine therapy.

MEASUREMENTS

Fracture rates and changes in bone turnover markers and bone mineral density.

RESULTS

Eleven RCTs were identified. The majority of trials included women with a mean age in the 60s; and women aged 75 and older and 80 and older were excluded from two studies. Fracture rates ranged from 0.9% to 11%, with AIs having a 1.5 times higher risk than tamoxifen or placebo. Fracture data were not systematically collected in many of these trials. In a small subpopulation of women, AIs were associated with higher markers of bone turnover and lower bone density. The relationship between age and fracture was not described.

CONCLUSION

AIs are associated with low bone density and high fracture risk in women with a mean age in their early 60s. There is a paucity of data describing the effect of baseline fracture risk factors, particularly age, and the longer-term effects on bone health in older women. Future research is needed regarding baseline fracture risk, interventions, and long-term effects on bone in this vulnerable population to inform management decisions to optimize AI duration and ensure quality of life after breast cancer.

Changes in bone biomarker concentrations and musculoskeletal symptoms among breast cancer patients initiating aromatase inhibitor therapy and women without a history of cancer

The objectives of this study were to examine: (1) changes in bone formation (osteocalcin) and bone resorption (cross-linked N-telopeptides of bone type I collagen [NTXs]) markers, as well as calcium, phosphorus, and intact parathyroid hormone, over the first 6 months of aromatase inhibitor (AI) therapy among a cohort of breast cancer patients compared with a group of unexposed women without a history of cancer; and (2) whether bone marker changes were associated with musculoskeletal pain. Eligible breast cancer patients (n = 49) and postmenopausal women without a history of cancer (n = 117) were recruited and followed for 6 months. At baseline, 3 months, and 6 months, a questionnaire was administered to assess pain and medication use, and a blood sample was drawn. Results showed that, among the breast cancer patients, calcium concentrations decreased significantly (-7.8% change; p = 0.013) and concentrations of NTXs increased significantly from baseline to 6 months (9.6% change; p = 0.012). Changes were not observed for women in the comparison group. Statistically significant differences in percent change between the breast cancer patients and the women in the comparison group were observed for calcium at 6 months (-7.8% versus 0.0%; p = 0.025), phosphorus at 6 months (-5.1% versus 16.7%; p = 0.003), NTXs at 6 months (9.6% versus -0.7%; p = 0.017), and osteocalcin at 6 months (11.5% versus -3.6%; p = 0.016). No statistically significant associations were observed between bone turnover marker changes and musculoskeletal pain among the breast cancer patients, although baseline NTXs were higher among women with onset or increase in pain compared with those reporting no pain (p = 0.08). Findings from this study suggest that AIs cause changes in bone turnover during the first 6 months of treatment; however, these changes are not associated with musculoskeletal pain. Breast cancer patients initiating AI therapy should be assessed and monitored for fracture risk using known clinical risk factors, including bone density, and managed appropriately.

Aromatase inhibitors and calcium absorption in early stage breast cancer

To investigate the effect of aromatase inhibitors (AI) on intestinal calcium absorption, measured using the gold-standard dual stable calcium isotope method. In this pilot study, we recruited 10 postmenopausal women with hormone receptor-positive breast cancer who planned to initiate AI therapy; women receiving chemotherapy were excluded. Women completed two 24 h inpatient calcium absorption study visits, the first prior to AI therapy and the second at least 6 weeks following onset of AI therapy. We calculated total fractional calcium absorption (TFCA) using the dose-corrected fractional recovery of two stable isotopes from 24 h urine collections. Ten postmenopausal women (mean±SD age, 66±7 years; 25(OH)D 40±7 ng/mL, and total calcium intake of 1,714±640 mg/day) exhibited no change in TFCA related to AI therapy (0.155±0.042 prior to and 0.160±0.064 following AI therapy, p=1.0). Subjects exhibited a surprisingly small decline in serum estradiol levels with AI therapy that was not statistically significant. However, there was a significant correlation between duration of AI therapy and the decline in serum estradiol levels (r=-0.65, p=0.040). In this pilot study, AI therapy did not decrease TFCA. Women with early stage breast cancer exhibited an unexpectedly low TFCA, most likely due to their high calcium intake. The null effect of AI therapy on TFCA might relate to the brief duration of AI therapy, the minimal effect of AI therapy on estradiol levels, subjects' high calcium intake or excellent vitamin D status.

Exemestane in early breast cancer: a review

The adjuvant treatment of women with endocrine-sensitive early breast cancer has been dominated for the last 40 years by tamoxifen. However, the side-effects associated with this therapy have prompted a search for safer and biochemically more selective endocrine agents and led to the development of the third-generation aromatase inhibitors (AIs) anastrozole, letrozole and exemestane. Promising results in advanced disease have paved the way for treating early breast cancer, and AIs are increasingly replacing tamoxifen in the adjuvant setting. Several large, randomized trials with AIs have been completed or are ongoing in women with early-stage breast cancer, documenting the significant impact that these drugs are making on the risk for recurrence of breast cancer. As a result, there is increasing and widespread use of AI therapy for the treatment of early-stage endocrine-responsive breast cancer. This review summarizes the data for exemestane in the adjuvant setting, showing that a switch to exemestane after 2 to 3 years of tamoxifen therapy is associated with a statistically significant survival benefit and is regarded as being sensitive by international and national experts.

Management of bone disease in patients undergoing hormonal therapy for breast cancer

Estrogen deficiency at menopause is associated with increased risk of bone loss and osteoporosis. Aromatase inhibitors (AIs) are increasingly being used for the treatment of postmenopausal hormone-sensitive breast cancer because of better disease-free survival compared with tamoxifen seen in clinical trials with AIs. This article reviews the effect of endocrine therapies of breast cancer on bone and the management of bone disease with these endocrine therapies. The effect of these therapies on bone mineral density and bone turnover along with possible interventions is discussed. AIs are also associated with skeletal-related events, which are not discussed.

Clinical review: Effect of endocrine therapies on bone in breast cancer patients

CONTEXT

Two common strategies are used to treat estrogen receptor-positive breast cancer in women: tamoxifen to inhibit estrogen action, and aromatase inhibitors (AIs) to block estrogen biosynthesis. Recent data suggest that AIs are more effective than tamoxifen in the adjuvant and advanced disease settings and are now being more commonly used. Tamoxifen, as a selective estrogen receptor modulator, exerts estrogenic effects to preserve bone, whereas the AIs profoundly lower estrogen levels and cause bone loss. Recent comparative studies of these agents provide extensive data on fracture rates, bone mineral density, and markers of bone formation and resorption.

OBJECTIVE

The aim of the study was to review the mechanistic effects of estrogen on bone and clinical data regarding bone density, bone turnover markers, and fracture rates in women with breast cancer taking tamoxifen or AIs.

EVIDENCE ACQUISITION AND SYNTHESIS

Data presented reflect a review of the literature and data integration from the perspective of the author's knowledge of the field.

RESULTS

Tamoxifen increases bone density and reduces fractures in postmenopausal women with breast cancer, whereas AIs increase rate of fracture, accelerate loss of bone mineral density, and enhance levels of markers of bone formation and resorption. Bisphosphonates and denosumab counteract the effects of the AIs on bone. Guidelines for management of AI-induced bone loss are available from several sources, but a simple algorithm guides decision making most effectively.

CONCLUSIONS

Endocrine therapy for postmenopausal women with breast cancer exerts substantial effects on bone, and guidelines are available to assist in the management of bone-related problems.

Doping and musculoskeletal system: short-term and long-lasting effects of doping agents

Doping is a problem that has plagued the world of competition and sports for ages. Even before the dawn of Olympic history in ancient Greece, competitors have looked for artificial means to improve athletic performance. Since ancient times, athletes have attempted to gain an unfair competitive advantage through the use of doping substances. A Prohibited List of doping substances and methods banned in sports is published yearly by the World Anti-Doping Agency. Among the substances included are steroidal and peptide hormones and their modulators, stimulants, glucocorticosteroids, β₂-agonists, diuretics and masking agents, narcotics, and cannabinoids. Blood doping, tampering, infusions, and gene doping are examples of prohibited methods indicated on the List. Apart from the unethical aspect of doping, as it abrogates fair-play's principle, it is extremely important to consider the hazards it presents to the health and well-being of athletes. The referred negative effects for the athlete's health have to do, on the one hand, by the high doses of the performance-enhancing agents and on the other hand, by the relentless, superhuman strict training that the elite or amateur athletes put their muscles, bones, and joints. The purpose of this article is to highlight the early and the long-lasting consequences of the doping abuse on bone and muscle metabolism.

Emerging drugs for the management of cancer treatment induced bone loss

AREAS COVERED IN THIS REVIEW

We focus our attention on data on the efficacy of currently available and emerging drugs for the management of cancer treatment induced bone loss (CTIBL) found in a PubMed research from 1997 till today.

IMPORTANCE OF THE FIELD

One of the most common and severe safety issues of the antihormonal therapy in both sexes is the CTIBL and the related fragility fractures. In postmenopausal women with estrogenic receptor positive breast cancer, the third-generation aromatase inhibitors (AIs) are the standard therapy. Observational retrospective studies have found that AIs treated patients had a high rate of bone loss and fracture risk (RR 1.3). Also in men with prostate cancer receiving androgen deprivation therapy, the increase in bone turnover and the consequent bone loss are very rapid and sustained significantly increasing the fracture risk.

WHAT THE READER WILL GAIN

The aim of our review is to provide the current evidences for the management of bone loss and fracture risk in this subpopulation.

TAKE HOME MESSAGE

The very high rate of bone loss and the high incidence of fractures indicate that cancer patients at risk of CTIBL need to be carefully monitored and stratified for fracture risk. Although there is a strong evidence of efficacy in prevention of bone loss and reduction of fracture risk for many drugs approved for postmenopausal osteoporosis (PMO) and male osteoporosis, for CTIBL there are actually no drugs approved for this indication.

Impact of aromatase inhibitors on bone health in breast cancer patients

Following the implementation of the third generation aromatase inhibitors in the treatment algorithms for early breast cancer, special attention has been given to the influence of these drugs on bone health. Due to their potent estrogen suppression, the aromatase inhibitors anastrozole and letrozole, as well as the aromatase inactivator exemestane, enhance bone loss in postmenopausal women reflected in decreasing levels of bone mineral density. Moreover, all major phase III trials involving aromatase inhibitors in the adjuvant setting have reported increased fracture rates. All in all, there is no hard evidence to suggest major differences between the individual compounds concerning their side-effects on bone. The consequences of AI therapy on bone are in addition modified by a variety of factors like the BMD level prior to therapy, time since menopause, and vitamin D status. Strategies to avoid bone loss during AI therapy have shown promising results. Thus, bisphosphonates have been shown to prohibit bone loss during AI therapy if used upfront. Novel treatment strategies, like antibodies against RANKL have been developed and promising preliminary results have been published from early trials. Standardized guidelines to avoid or minimize bone loss during AI therapy have been developed, in most countries involving calcium and vitamin D supplementation, as well as BMD measurements to identify patient subgroups demanding bisphosphonate therapy.

Pharmacology and clinical applications of selective estrogen receptor modulators

Compounds that can be described as selective estrogen receptor modulators (SERMs) have expanded dramatically over the past two decades. The ability of SERMs to act as estrogens in certain tissues while remaining inert or acting as an anti-estrogen in other tissues has opened up opportunities for treating specific estrogen-modulated diseases without accepting the risk of systemic estrogen activity. SERM development has resulted in significant therapeutic advances for breast cancer, osteoporosis and potentially other diseases associated with the menopause. After the publication of the Women's Health Initiative, interest in compound selectivity that reduces menopausal symptoms while protecting bone, breast, uterus and the heart has increased. Future SERMs may also have a therapeutic profile that can be tailored to specific patient populations, including men. This review paper summarizes the characteristics of different SERMs from various pharmacological categories and the feasibility and scope of their use for a large range of disease/health conditions.

Exemestane: a review of its use in postmenopausal women with breast cancer

Exemestane (Aromasin) is an orally active steroidal irreversible inactivator of the aromatase enzyme indicated as an adjuvant treatment in postmenopausal women with estrogen receptor-positive early-stage breast cancer following 2-3 years of adjuvant treatment with tamoxifen, and for the treatment of advanced breast cancer in postmenopausal women whose disease has progressed following tamoxifen or other antiestrogen therapy. Exemestane is effective for the treatment of postmenopausal women with early-stage or advanced breast cancer. In early-stage disease, switching to exemestane for 2-3 years after 2-3 years of adjuvant tamoxifen treatment was more effective in prolonging disease-free survival than continuing tamoxifen therapy, although it was not associated with an overall survival benefit, except in those with estrogen receptor-positive or unknown receptor status disease when nodal status, hormone replacement therapy (HRT) and chemotherapy use were adjusted for. Moreover, preliminary data suggest that the efficacy of exemestane is generally no different to that of tamoxifen in the primary adjuvant treatment of early-stage breast cancer, although exemestane may be better in prolonging the time to distant recurrence. In advanced disease, exemestane showed equivalent efficacy to megestrol in patients with disease refractory to tamoxifen and an efficacy not significantly different from that of fulvestrant in those refractory to a nonsteroidal aromatase inhibitor. Available data, some of which are limited, suggest exemestane is also effective in the first-line hormonal treatment of advanced breast cancer in postmenopausal women. Exemestane is generally well tolerated, although the potential bone fracture risk of the drug requires further investigation. Results from directly comparative trials indicating the efficacy, tolerability and bone fracture risk of exemestane relative to third-generation aromatase inhibitors and other agents in both early-stage and advanced disease, as well as the optimal sequence of endocrine therapies, are awaited with interest. In the meantime, switching to exemestane should be considered in postmenopausal women who have received 2-3 years of adjuvant tamoxifen treatment for early-stage breast cancer, and is an emerging treatment option for postmenopausal women with advanced breast cancer refractory to one or more antiestrogen therapies.

Safety of adjuvant endocrine therapies in hormone receptor-positive early breast cancer

Postmenopausal patients with hormone-sensitive early breast cancer are typically treated with adjuvant endocrine therapy, which significantly reduces the risk of recurrence. Because treatment is of a long duration, side effects from adjuvant therapy can be problematic. The aromatase inhibitors (AIS) are replacing tamoxifen as first-line treatment agents for early breast cancer. Here, we present the side-effect data associated with AIS in relation to bone, gynecologic, and cardiovascular health and to arthralgia and myalgia. Although AIS have been shown to decrease bone density, increase arthralgia, and affect vaginal health, these adverse events are usually manageable, and several strategies can be followed to improve quality of life in women on AI treatment. To optimize adherence to therapy. It is important that these issues are addressed so that women can benefit from treatment.

Aromatase inhibitors, efficacy and metabolic risk in the treatment of postmenopausal women with early breast cancer

The third-generation aromatase inhibitors (AIs), letrozole, anastrozole and exemestane, are becoming the first choice endocrine drugs for post-menopausal women with breast cancer, since they present greater efficacy when compared with tamoxifen in both adjuvant and metastatic setting. In particular, several large and well designed trials have suggested an important role for AIs in the adjuvant treatment of postmenopausal women with estrogen-receptor positive breast cancer either in the upfront, sequential or extended adjuvant mode. Overall, AIs are associated with a small but significant improvement in disease free survival. The expanding use of AIs in the treatment of early breast cancer means that individual patients will be exposed to the agents for longer durations, making it increasingly important to establish their long-term safety. This review focused on the effects of AIs on bone metabolism, serum lipids and cardiovascular risk. AIs have adverse effects on bone turnover with a reduction of bone mineral density and an increase in the rate of fragility fractures. With respect to tamoxifen AIs present lower thrombotic risk and a less favorable impact on lipid profile, whereas the true effects on cardiovascular risk still remain to be clarified. An adequate monitoring of bone mineral density (BMD) and lipid profile could be recommended for post-menopausal women candidate to AIs.

Cancer treatment-related bone disease

Bone health may be impaired in many patients being treated for cancer. Primary tumors that reside in or form metastases to bone can result in compromised skeletal integrity. It has also been increasingly recognized that patients undergoing therapies for treatment of cancer are at higher risk of bone loss. These include androgen-deprivation therapy for prostate cancer and aromatase inhibitor therapy for breast cancer, among others. Hypogonadism induced by many of these cancer treatments results in bone loss and increases the risk of osteoporosis and fractures. Progress has been made in identifying the role of oral and intravenous bisphosphonates to prevent bone loss in these patients. This review discusses bone loss associated with cancer treatments, with a focus on breast cancer, prostate cancer, and survivors of childhood malignancies.

Safety of adjuvant endocrine therapy in postmenopausal women with breast cancer

The use of aromatase inhibitors (AIs) as adjuvant endocrine therapy for hormone-sensitive breast cancer is increasing, as these drugs are more effective than tamoxifen alone in improving disease-free survival in breast cancer patients-whether used in lieu of tamoxifen as upfront therapy or after tamoxifen treatment periods of 2 years or longer. AIs differ from tamoxifen in their mechanism of action, effectively suppressing estrogen levels in postmenopausal women to near-undetectable levels. AI-associated adverse events largely mimic menopausal symptoms, including hot flashes, losses in bone mineral density, gynecologic symptoms, and arthralgias. The AIs lack the infrequent but potentially serious adverse events associated with tamoxifen (eg, endometrial cancer, thromboembolic events, and stroke). Large randomized studies of AIs in the adjuvant setting have not demonstrated an adverse effect on lipids and cardiovascular health, but postmenopausal women receiving AIs are at risk for age-related changes in lipid parameters and an increased risk for cardiovascular events. To optimize the overall benefits of adjuvant endocrine therapy with an AI, patients should be monitored for bone loss and cardiovascular risk factors, and symptoms such as joint pain and vaginal dryness should be anticipated and managed proactively.

Biochemical markers of bone turnover: potential use in the investigation and management of postmenopausal osteoporosis

INTRODUCTION

The aim was to analyse data on the use of biochemical bone turnover markers (BTM) in postmenopausal osteoporosis.

METHODS

We carried out a comparative analysis of the most important papers concerning BTM in postmenopausal osteoporosis that have been published recently.

RESULTS

The BTM levels are influenced by several factors. They are moderately correlated with BMD and subsequent bone loss. Increased levels of bone resorption markers are associated with a higher risk of fracture. Changes in the BTM during the anti-osteoporotic treatment (including combination therapy) reflect the mechanisms of action of the drugs and help to establish their effective doses. Changes in the BTM during the anti-resorptive treatment are correlated with their anti-fracture efficacy.

CONCLUSION

Biological samples should be obtained in a standardised way. BTM cannot be used for prediction of the accelerated bone loss at the level of the individual. BTM help to detect postmenopausal women who are at high risk of fracture; however, adequate practical guidelines are lacking. BTM measurements taken during the anti-resorptive therapy help to identify non-compliers. They may improve adherence to the anti-resorptive therapy and the fall in the BTM levels that exceeds the predefined threshold improves patients' persistence with the treatment. There are no guidelines concerning the use of BTM in monitoring anti-osteoporotic therapy in postmenopausal women.

Cancer treatment-induced bone loss in breast and prostate cancer

PURPOSE

Bone loss resulting from the treatment of breast and prostate cancer is an emerging problem. Bisphosphonates have a potential role in the prevention of this cancer treatment-induced bone loss (CTIBL).

METHODS

Studies evaluating the incidence and prevalence of CTIBL in early breast and prostate cancer patients and trials evaluating the preventative role of bisphosphonates were identified by a search of the PubMed and Cochrane Library databases through the end of March 2008. Reference lists from retrieved articles were cross referenced, and further information was obtained from relevant scientific meetings.

RESULTS

Several therapies commonly used in the treatment of women and men with breast and prostate cancers, in particular the aromatase inhibitors (AIs) for breast cancer and androgen deprivation therapy (ADT) for prostate cancer, are associated with significant bone loss and with an increase in fracture risk. The use of bisphosphonates seems to attenuate the bone loss, although the long-term impact remains unclear because of insufficient follow-up.

CONCLUSION

Adjuvant endocrine therapy with an AI or androgen deprivation can be considered a risk factor for the development of osteopenia, osteoporosis, and bone fracture, which can be mitigated by appropriate bisphosphonate therapy. Clear identification of risk factors for osteoporosis in individual patients should aid treatment decisions about whether to use bisphosphonates when starting or switching to an AI or ADT. Patients need to be educated about this risk and other measures to avoid this complication, including lifestyle modifications that may benefit their general and bone health.

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.

Bone health issues in women with early-stage breast cancer receiving aromatase inhibitors

Bone health is an important issue for women with all stages of breast cancer, but especially those with early-stage breast cancer receiving aromatase inhibitors (AIs). AIs have been shown to reduce bone mineral density and are associated with an increased incidence of fractures. Although AIs significantly improve survival times in early-stage breast cancer patients, many of these patients eventually develop metastatic bone disease. Therefore, identifying effective strategies for preventing bone metastases is needed. Results of preclinical studies with bisphosphonates show increased tumor cell kill in several breast cancer cell lines, but study results evaluating this class of drugs for prevention of bone metastases in women with early-stage breast cancer receiving adjuvant therapies have been inconsistent. However, several large studies to clarify the role of bisphosphonates in maintaining or improving bone health in these women are under way.

Cancer treatment-induced bone loss

PURPOSE OF REVIEW

Patients treated for cancer may be at risk for osteoporosis and fracture. Evaluation and treatment of patients with cancer treatment-induced bone loss should lead to fewer fractures. This review will help clinicians learn to identify, evaluate and treat cancer patients at risk.

RECENT FINDINGS

Survivors of childhood cancers and patients made hypogonadal by treatment for breast or prostate cancer are clearly at risk for osteoporosis and fracture. Use of aromatase inhibitors rather than tamoxifen for breast cancer will likely lead to more osteoporosis. Bisphosphonates prevent bone loss in many patients at risk.

SUMMARY

For many cancer patients, treatment with calcium, vitamin D, and bisphosphonates will likely decrease the consequences of cancer treatment-induced bone loss, namely fractures.

Safety of aromatase inhibitors in the adjuvant setting

The third-generation aromatase inhibitors (AIs) letrozole, anastrozole, and exemestane are replacing tamoxifen as adjuvant therapy in most postmenopausal women with early breast cancer. Although AIs have demonstrated superior efficacy and better overall safety compared with tamoxifen in randomized controlled trials, they may not provide the cardioprotective effects of tamoxifen, and bone loss may be a concern with their long-term adjuvant use. Patients require regular bone mineral density monitoring, and prophylactic bisphosphonates are being evaluated to determine whether they may protect long-term bone health. AIs decrease the risks of thromboembolic and cerebrovascular events compared with tamoxifen, and the overall rate of cardiovascular events in patients treated with AIs is within the range seen in age-matched, non-breast-cancer populations. AIs are also associated with a lower incidence of endometrial cancer and fewer vaginal bleeding/discharge events than tamoxifen. Compared with tamoxifen, the incidence of hot flashes is lower with anastrozole and letrozole but may be higher with exemestane. Generally, adverse events with AIs are predictable and manageable, whereas tamoxifen may be associated with life-threatening events in a minority of patients. Overall, the benefits of AIs over tamoxifen are achieved without compromising overall quality of life.

Safety profiles of tamoxifen and the aromatase inhibitors in adjuvant therapy of hormone-responsive early breast cancer

Adjuvant endocrine therapy plays an important role in the management of hormone-receptor-positive early breast cancer, and has increased life expectancy for millions of women. Many patients receive adjuvant treatment for at least 5 years following tumor resection, hence good long-term safety is important for endocrine agents to gain widespread acceptance. Tamoxifen has been used as adjuvant therapy for early breast cancer for many years, and safety data have been well documented, but a poor risk:benefit profile limits treatment duration to 5 years. Increased efficacy over tamoxifen and good tolerability have recently made the third-generation aromatase inhibitors (AIs) the first-choice agents for adjuvant endocrine therapy; however, it is currently not known whether AI therapy, like tamoxifen, will be limited to 5 years. Many side effects of endocrine therapy, such as hot flushes and mood disturbances, are related to estrogen deprivation and are common to tamoxifen and AIs, reflecting the mechanism of action of these drugs. In addition, tamoxifen has estrogenic effects that are beneficial in some tissues: tamoxifen lowers serum cholesterol levels and protects against bone loss and cardiovascular disease, but is also associated with potentially life-threatening side effects, such as endometrial cancer and thromboembolic disease. As AIs lack estrogenic activity, they are not associated with these serious adverse events. Clinical trials comparing AIs with tamoxifen in the adjuvant setting have shown that AIs are well tolerated and are associated with a lower incidence of gynecological symptoms and hot flushes than tamoxifen. However, AIs are associated with musculoskeletal side effects, such as arthralgia, myalgia and bone loss, but these events are preventable or manageable. The effects of AIs on lipid metabolism and the cardiovascular system are still debatable, but placebo-controlled trials provide no evidence to suggest that AIs adversely affect these systems. Furthermore, the AIs allow women to maintain a good quality of life, comparable with women receiving tamoxifen or placebo, and are a cost-effective therapeutic option. Ongoing trials will provide more information regarding the long-term effects of AI therapy and will provide comparative data on the efficacy and safety of the different AIs, thereby helping to determine the optimal treatment strategy for these highly effective and well-tolerated drugs.

Estrogen-dependent increase in bone turnover and bone loss in postmenopausal women with breast cancer treated with anastrozole. Prevention with bisphosphonates

Aromatase inhibitors have demonstrated their superiority to tamoxifen as adjuvant therapy for early breast cancer in postmenopausal women, but are associated with an increased risk of fractures. The aim of our study was to analyze bone loss, bone turnover and their determinants in postmenopausal women treated with anastrozole. We investigated bone loss and bone turnover markers (BTM) in a prospective open cohort study of 118 postmenopausal women treated with anastrozole for an early hormone-dependent breast cancer. Women without osteoporosis were not treated and compared with an age-matched control group of 114 healthy women. Osteoporotic patients (T-score<or=-2.5 S.D.) received weekly risedronate. Bone mineral density (BMD), and the BTM serum osteocalcin and serum C-terminal cross linking telopeptide of type I collagen (CTX) and 17beta-estradiol were measured at baseline and 1 year later. In the surveillance group, anastrozole induced after 1 year of treatment a marked bone loss at the spine (mean+/-S.E.M., [95% confidence interval]) -3.3+/-0.4% [-4.1 to -2.5]), and hip (2.8+/-0.4% [-3.6 to -2]) that was significantly greater than in controls (p<0.0001). Anastrozole induced an increase in bone remodelling: osteocalcin (+36.6%, p<0.0001) and CTX (+34%, p<0.0001). In univariate models, a recent menopause, a low body mass index, a complete chemotherapy (>or=6 courses) and a marked antiestrogenic response--defined by a level of 17beta-estradiol<or=2 pg/ml at 1 year or a decrease >50% between baseline and 1 year--were associated with greater bone loss. In multivariate model, women in the highest quartile of bone loss at the spine (>5.6% at 1 year) and hip (>4.9%) had a marked antiestrogenic response with OR of 10.4 [95% C.I. 1.9-57.2] (p=0.007) and 5.7 [1.3-25] (p=0.024) respectively. Among patients in the surveillance group, those with a normal T-score at both sites (n=46) had also a significant bone loss at spine -3.3+/-0.5% [-4.3 to -2.3], p<0.0001 and at the hip -2.9+/-0.6% [-4.1 to -1.7] p<0.0001. In osteoporotic women treated simultaneously with anastrozole and risedronate, bone loss was prevented at hip, and increased at the spine (+4.1+/-0.9% [2.3 to 5.9], p=0.008), and BTM decreased (-24%, -39% for CTX, p=0.003 and 0.001 vs. changes in the untreated group). Anastrozole increases bone turnover and induces an accelerated bone loss that is significantly related to the suppression of 17beta-estradiol production induced by aromatase inhibitor. The bisphosphonate risedronate prevents anastrozole induced bone loss.

Cancer-associated bone disease

Patients with cancer are at risk for many events involving the skeleton, including metastatic disease of bone and treatment-related bone loss. Cancer-related therapies that can affect bone include hormonal therapy, chemotherapy, and the use of glucocorticoids. Screening for bone loss, with lifestyle modifications and the early use of anti-osteoporosis therapies such as bisphosphonates, may decrease bone loss and reduce the risk of fracture. This article reviews risk factors and mechanisms associated with cancer-related bone loss and metastases as well as strategies for the detection of bone-related complications of cancer and therapies to treat these complications. This article focuses on the more common cancers with adverse skeletal effects: breast cancer, prostate cancer, and multiple myeloma.