Bone loss in patients with breast cancer receiving aromatase inhibitors and associated treatment strategies. Cancer Treat Rev. 2008;34 Suppl 1:S31-S42. [PMID: 18486346 DOI: 10.1016/j.ctrv.2008.03.005]

Osteoporosis Associated with Breast Cancer Treatments Based on Types of Hormonal Therapy: A Cross-Sectional Study Using Korean National Sample Data

Background and Objectives: This study aimed to investigate osteoporosis-related treatments and the overall anticancer drug treatment tendencies, with a focus on selective estrogen receptor modulators (SERMs) and aromatase inhibitors (AIs), in Korean patients with breast cancer from 2010 to 2019. Materials and Methods: Data were obtained from the Health Insurance Review and Assessment Service. Patients with breast cancer (International Classification of Diseases, 10th Revision code: C50) as a principal diagnosis at least once from 2010 to 2019 were included. Those with osteoporosis (M80, M81, or M82) as a principal or sub-diagnosis or those who received osteoporosis treatment at least once were categorized as the osteoporosis-related treatment group, and others as the non-osteoporosis-related treatment group. The trends of drug prescriptions and treatment costs in patient groups were evaluated using descriptive statistics. Results: Among all included patients, those aged 45-54 years (40.20%) without osteoporosis treatment and those aged 55-64 years (34.11%) with osteoporosis treatment were the most common. SERM was the most commonly prescribed anticancer drug (29.20%) in the entire patient group, followed by AIs (20.83%). Patients without osteoporosis treatment had the highest prescription rate of SERM (31.48%), and those with osteoporosis treatment had a higher prescription rate of AIs (34.28%). Additionally, SERM and AIs were prescribed most frequently before and after the age of 55 years, respectively, regardless of the presence of treatment. Conclusions: This study found that osteoporosis-related treatment and patient age were associated with anticancer drug prescriptions. The present findings would help clinicians and researchers in the clinical diagnosis and treatment of breast cancer.

Bone Health Following Bariatric Surgery: An Update

Obesity rates are increasing rapidly, and bariatric surgery is currently the most effective tool for weight loss. Recently, bariatric surgery induced bone loss has gained attention. Such detrimental effect on bone is multifactorial and causes may include nutrient deficiencies, gut and gonadal hormonal changes, mechanical unloading, loss of lean mass, increased bone marrow fat, and increased risk of fall. This review describes the available evidence on bone loss and fracture risk following bariatric surgery and summarizes the guidelines on the topic. Increased bone resorption starts early postsurgery, and bone markers peak at 1-2 yr. Across studies, the drop in areal bone mineral density is inconsistent at the lumbar spine, while a 2%-5% drop at 6 mo and a 6%-10.5% at 9-12 mo are observed at the total hip. Conversely, studies using quantitative CT showed a 6%-7% decrease in volumetric bone mineral density at the lumbar spine at 6-12 mo postsurgery. These studies also report significant bone loss at the radius and tibia, in addition to alteration in bone microarchitecture. Fracture risk increases 2 yr after surgery, more so following malabsorptive procedures. Fractures were reported at axial, weight bearing sites and at appendicular sites. The available evidence is very heterogeneous, and mostly derived from studies on Roux-en-y gastric bypass in premenopausal women. Data on restrictive procedures is scarce. Our findings suggest that the early postoperative phase represents the "golden window" to intervene and promote bone health. More research is needed to determine the effect of different bariatric procedures on bone, to identify optimal interventions to prevent bone loss and to characterize high risk individuals who should be targeted.

Novel insights into the complex architecture of osteoporosis molecular genetics

Osteoporosis is a prevalent osteodegenerative disease and silent killer linked to a decrease in bone mass and decline of bone microarchitecture, due to impaired bone matrix mineralization, raising the risk of fracture. Nevertheless, the process of bone matrix mineralization is still an unsolved mystery. Osteoporosis is a polygenic disorder associated with genetic and environmental risk factors; however, the majority of genes associated with osteoporosis remain largely unknown. Several signaling pathways regulate bone mass; therefore, dysregulation of a single signaling pathway leads to metabolic bone disease owing to high or low bone mass. Parathyroid hormone, core-binding factor α-1 (Cbfa1), Wnt/β-catenin, the receptor activator of the nuclear factor kappa-B (NF-κB) ligand (RANKL), myostatin, and osteogenic exercise signaling pathways play pivotal roles in the regulation of bone mass. The myostatin signaling pathway increases bone resorption by activating the RANKL signaling pathway, whereas osteogenic exercise inhibits myostatin and sclerostin while inducing irisin that consequentially activates the Cbfa1 and Wnt/β-catenin bone formation pathways. The aims of this review are to summarize what is known about osteoporosis-related signaling pathways; define the role of these pathways in osteoporosis drug discovery; focus light on the link between bone, muscle, pancreas, and adipose integrative physiology and osteoporosis; and underline the emerging role of osteogenic exercise in the prevention of, and care for, osteoporosis, obesity, and diabetes.

Uterine pathology in transmasculine persons on testosterone: a retrospective multicenter case series

BACKGROUND

As part of transition, transmasculine persons often use testosterone gender-affirming hormone therapy; however, there is limited data on its long-term effects. The impact of exogenous testosterone on uterine pathology remains unclear. While testosterone achieves amenorrhea in the majority of this population, persistence of abnormal uterine bleeding can be difficult to manage. Excess androgens in cisgender females are associated with pathologic uterine processes such as polycystic ovary syndrome, endometrial hyperplasia, or cancer. There are no guidelines for management of abnormal uterine bleeding or endometrial surveillance in this population.

OBJECTIVE

The aim of this study was to describe the characteristics of uterine pathology after the initiation of testosterone in transmasculine persons.

MATERIALS AND METHODS

A retrospective, multicenter case series was performed. Uterine pathology reports of transmasculine persons who received testosterone and subsequently underwent hysterectomy were reviewed. The endometrial phase and endometrial thickness were recorded.

RESULTS

A total of 94 subjects met search criteria. The mean age of participants was 30 ± 8.6 years, and the mean interval from initiation of testosterone to hysterectomy was 36.7 ± 36.6 months. Active endometrium was found in the majority of patients (n = 65; 69.1%). One patient had complex hyperplasia without atypia. There were no cases of endometrial cancer.

CONCLUSION

Despite amenorrhea in the majority of transmasculine persons on testosterone, endometrial activity persists with predominantly proliferative endometrium on histopathology. Individualized counseling for abnormal uterine bleeding is encouraged in this patient population.

Effectiveness of bisphosphonate combined with activated vitamin D in patients with aromatase inhibitor-induced osteoporosis after breast cancer operation

Objectives

We compared the effectiveness of bisphosphonates combined with activated vitamin D administered for therapy of aromatase inhibitor-induced osteoporosis after a breast cancer operation and primary postmenopausal osteoporosis through propensity score matching.

Methods

Forty-eight postmenopausal patients with estrogen receptor-positive early breast cancer, who had postoperative adjuvant treatment with aromatase inhibitors and whose T-score of bone mineral density (BMD) decreased below −2.5 (AI group), and 48 patients of primary postmenopausal osteoporosis (PO group) enrolled in this retrospective observational study. They were administered monthly risedronate or minodronate, and daily alfacalcitol or eldecalcitol were combined. Their BMD (L2–4, L-BMD), serum-corrected calcium, serum phosphate, tartrate-resistant acid phosphatase 5b (TRACP-5b), bone alkaline phosphatase (BAP), estimated glomerular filtration rate, urine calcium/creatinine ratio, intact-parathyroid hormone, and 25-hydroxy vitamin D were measured before treatment and until 24 months.

Results

L-BMD values increased with time compared with the baseline values in each group, and there was no significant difference in the groups. Percentage value of TRACP-5b decreased rapidly after 6 months and maintained low level until 24 months in both groups. Percentage value of BAP in the AI group decreased continuously until 24 months. In contrast, the percentage change in the PO group plateaued after 6 months.

Conclusions

It is suggested that monthly oral bisphosphonate combined with activated Vitamin D is an effective therapy to increase BMD in the aromatase inhibitor-induced osteoporosis after breast cancer operation. Monitoring of kidney function and concentration of Ca in blood and urine may be necessary.

Radioprotective Effects of Amifostine and Lycopene on Human Peripheral Blood Lymphocytes In Vitro

BACKGROUND

Radiation protection is a pivotal challenge for radiation workers employed in medical fields, industry, and also space professionals with an increasing role in medical diagnostic and therapeutic applications. Radioprotective effects of amifostine and lycopene and their ability to moderate the level of radiation-induced chromosomal aberrations were investigated using the dicentric chromosome assay.

METHODS

Parallel human whole blood samples, pretreated with amifostine (250 μg/mL), lycopene (5 μg/mL), and/or their combinations were irradiated for 30 minutes with ⁶⁰Co γ rays (1, 2, 3, and 4 Gy) with a dose rate of 98.46 cGy/min at SAD = 100 cm, in vitro and cocultured with control groups. The frequencies of chromosomal aberrations in the lymphocyte of the cells were analyzed.

RESULTS

There were no apparent chromosome aberrations in controls and also in the drug-treated groups in the absence of radiation. Radiodrug treatment significantly decreased frequency of the radiation-induced chromosome aberrations compared with radiation alone (P < .05). Amifostine reduced the frequency of radiation-induced dicentrics by 15.8%, 21.9%, 4.5%, and 11.6%, with dose protection factors (DPFs) of 1.2 ± 0.02, 1.3 ± 0.1, 1.05 ± 0.03, and 1.13 ± 0.02. Lycopene reduced the frequency by 17.2%, 3.07%, 1.63%, and 16.6%, with DPFs of 1.21 ± 0.12, 1.03±0.05, 1.02±0.03 and 1.12±0.03. The combination treatment reduced the frequency by 28%, 24.9%, 9%, and 31.2%, with DPFs of 1.38 ± 0.06, 1.33 ± 0.06, 1.09 ± 0.02, and 1.45 ± 0.03 with radiation doses of 1, 2, 3, and 4 Gy, respectively.

CONCLUSIONS

It can be suggested that pretreatment with combined amifostine and lycopene may reduce the extent of ionizing radiation damage in cells.

Training-related improvements in musculoskeletal health and balance: a 13-week pilot study of female cancer survivors

Cancer survivors often experience poor post-treatment musculoskeletal health. This study examined the feasibility of combined aerobic and resistant training (CART) for improving strength, skeletal health and balance. Cancer survivors (n = 24) were identified by convenience sampling in Los Angeles County with 11 survivors consenting to 13 weeks of CART. Pre- and post-intervention assessments of bone mineral density (BMD), strength, flexibility and biomarker analysis were performed. Paired t-test analysis suggested increases in lower and upper body strength. The average T-score for BMD at the femoral neck improved from -1.46 to -1.36 and whole body BMD improved from -1.65 to -1.55. From baseline to follow-up, participants also displayed decreases in sway velocity on the eyes open (7%) and eyes closed (27%) conditions. Improvement in lower body strength was associated with increases in lean body mass (LBM) (r = 0.721) and an inverse association was observed between sway velocity and LBM (r = 0.838). Age and time since last treatment were related with biomarkers of anabolic growth (IGF-1, IGFbp-3) and bone (DPD, BAP). In summary, observed physiological changes were consistent with functional improvements, suggesting that isometric and dynamic exercise prescription may reduce the risk for falls and fall-related fractures among survivors.

Caring for the breast cancer survivor’s health and well-being

The breast cancer care continuum entails detection, diagnosis, treatment, and survivorship. During this time, focus on the whole woman and medical concerns beyond the breast cancer diagnosis itself is essential. In this comprehensive review, we critically review and evaluate recent evidence regarding several topics pertinent to and specific for the woman living with a prior history of breast cancer. More specifically, we discuss the most recent recommendations for contraceptive options including long-acting reversible contraception and emergency contraception, fertility and pregnancy considerations during and after breast cancer treatment, management of menopausal vasomotors symptoms and vulvovaginal atrophy which often occurs even in young women during treatment for breast cancer. The need to directly query the patient about these concerns is emphasized. Our focus is on non-systemic hormones and non-hormonal options. Our holistic approach to the care of the breast cancer survivor includes such preventive health issues as sexual and bone health,which are important in optimizing quality of life. We also discuss strategies for breast cancer recurrence surveillance in the setting of a prior breast cancer diagnosis. This review is intended for primary care practitioners as well as specialists caring for female breast cancer survivors and includes key points for evidence-based best practice recommendations.

Running away from side effects: physical exercise as a complementary intervention for breast cancer patients

The number of breast cancer survivors increases every year, thanks to the development of new treatments and screening techniques. However, patients present with numerous side effects that may affect their quality of life. Exercise has been demonstrated to reduce some of these side effects, but in spite of this, few breast cancer patients know and follow the exercise recommendations needed to remain healthy. In this review, we describe the different breast cancer treatments and the related side effects and implications of exercise in relation to these. We propose that exercise could be an integrative complementary intervention to improve physiological, physical and psychological factors that affect survival and quality of life of these patients. For that reason, the main objective of this review is to provide a general overview of exercise benefits in breast cancer patients and recommendations of how to design exercise interventions in patients with different side effects.

The efficacy of bisphosphonates in preventing aromatase inhibitor induced bone loss for postmenopausal women with early breast cancer: a systematic review and meta-analysis

Objectives. We aim to determine the efficacy of bisphosphonates in preventing aromatase inhibitor induced bone loss (AIBL) in postmenopausal women with early breast cancer. The secondary objective was to determine the safety of bisphosphonates. Materials and Methods. We searched electronic databases in a time period of 1995 January to 2013 June. Random effects meta-analytical models were used; between study heterogeneity and publication bias was assessed. Results. A total of six eligible studies reported the BMD T score of LS at 12 months and from that 3 trials of Zoledronic acid compared the change in BMD in immediate ZOL versus delayed ZOL done with subgroups like patients with normal BMD at baseline (OR = 5.402, 95% CI = 1.329-21.959, P value = 0.018) and osteopenic BMD at baseline (OR = 4.008, 95% CI = 2.249-7.143, P value = 0.0002). Both had a significant decrease in BMD that favoured the delayed ZOL; 3 trials of risedronate and ibandronate also had a significant decrease in BMD in AIs alone group. Immediate ZOL versus delayed ZOL also showed increased risk of getting an ADR in immediate group. Conclusion. Third generation bisphosphonates has an effect on BMD of patients who are on treatment of AIs in breast cancer. Furthermore, the patients treated with immediate ZOL had a significantly high risk of musculoskeletal ADR's than patients with delayed ZOL.

Adjuvant bisphosphonates in breast cancer: has the time come?

SUMMARY Bone metabolism is highly affected by changes in ovarian function, which is a common consequence of the treatment of breast cancer patients. Osteopenia and osteoporosis increase the risk of fractures, which are associated with profound loss in quality of life. Bisphosphonates are used with the objective of preventing bone loss in patients with osteoporosis, but data suggest that agents such as zoledronic acid might play a role in the prevention of metastatic disease and therefore have been evaluated in numerous randomized trials in the adjuvant setting. This review article will discuss and analyze the available data regarding the use of bisphosphonates in the adjuvant setting for breast cancer patients. It will focus on the use of bisphosphonates as anticancer agents, but will also discuss the use of these agents for the prevention of bone loss.

Aromatase inhibitor-associated bone loss and its management with bisphosphonates in patients with breast cancer

Postmenopausal women have an increased risk of osteopenia and osteoporosis due to loss of the bone-protective effects of estrogen. Disease-related processes may also contribute to the risk of bone loss in postmenopausal women with breast cancer. One of the most common and severe safety issues associated with cancer therapy for patients with breast cancer is bone loss and the associated increase in risk of fractures. This paper reviews the recent literature pertaining to aromatase inhibitor (AI)-associated bone loss, and discusses suggested management and preventative approaches that may help patients remain on therapy to derive maximum clinical benefit. A case study is presented to illustrate the discussion. We observed that AIs are in widespread use for women with hormone receptor-positive breast cancer and are now recommended as adjuvant therapy, either as primary therapy or sequential to tamoxifen, for postmenopausal women. AIs target the estrogen biosynthetic pathway and deprive tumor cells of the growth-promoting effects of estrogen, and AI therapies provide benefits to patients in terms of improved disease-free survival. However, there is a concern regarding the increased risk of bone loss with prolonged AI therapy, which can be managed in many cases with the use of bisphosphonates and other interventions (eg, calcium, vitamin D supplementation, exercise).

Effects of zoledronic acid on bone mineral density during aromatase inhibitor treatment of Korean postmenopausal breast cancer patients

The age distribution of breast cancer patients in Korea, where most are less than 60 years of age and have recently entered menopause, differs from that in the West. The aim of this study was to evaluate bone mineral density (BMD) changes in Korean breast cancer patients treated with an aromatase inhibitor (AI) either alone or in combination with zoledronic acid (ZA). Changes in BMD of the lumbar spine and hip were evaluated in 107 patients receiving AI treatment, of which 59 were treated in combination with ZA. The mean age of the patients was 54.9 years, and the median follow-up period was 38.2 months. With AI treatment alone, BMD loss was significant (all P < 0.0001) in the lumbar spine and hip 12 months (4.18 and 3.95%, respectively), 24 months (6.28 and 5.44%), and 36 months (8.17 and 6.82%) after treatment. In contrast, the combination treatment resulted in increased BMD in the lumbar spine and hip 12 months (2.45 and 0.89%, respectively), 24 months (3.51 and 1.03%), and 36 months (3.85 and 1.80%) after treatment. BMD loss in the lumbar spine was significantly greater in AI alone-treated women who had entered menopause within the past year compared with those who had entered menopause more than 1 year ago, when measured 12 and 24 months after treatment (P = 0.017 and 0.021, respectively). Importantly, ZA effectively inhibited AI-associated bone loss, independent of the postmenopausal interval. Because the proportion of patients in this study who had recently entered menopause was high, bone loss in Korean breast cancer patients treated with AI alone was higher than data reported from the Arimidex, Tamoxifen Alone or in Combination (ATAC) trial. In conclusion, we have shown that ZA is very effective in preventing AI-induced bone loss in Korean postmenopausal breast cancer patients.

Skeletal imaging effects of pamidronate therapy in osteosarcoma patients

BACKGROUND

After observing metaphyseal changes in pediatric and young adult patients with osteosarcoma who were treated with pamidronate, we initiated a retrospective study to identify bone findings on computed radiography of the chest and extremities, chest CT, extremity MRI, and radionuclide bone scans in this population.

OBJECTIVE

To review the generalized skeletal imaging findings on computed radiography, CT, and MR examinations in patients with osteosarcoma (OS) receiving pamidronate.

MATERIALS AND METHODS

A retrospective review of 40 patients with newly diagnosed OS (mean age, 16.5 years) receiving pamidronate with chemotherapy were identified at one institution. Computed radiography, CT, MR, and bone scans on 36 patients were reviewed for osseous changes.

RESULTS

Dense metaphyseal bands at the growth plates in long bones, epiphyseal ossification centers, anterior rib ends, sternum and spine were observed. Osseous changes occurred on CT in 69% of patients, and on computed chest radiography in 53%. Bone-within-bone appearance in the spine and ossification centers was identified on computed radiography in 36%.

CONCLUSION

OS patients treated with pamidronate can develop metaphyseal sclerotic bands as well as epiphyseal and vertebral endplate sclerosis progressing to a bone-within-bone appearance. Findings occur more frequently in younger patients with open epiphyses.

Strength training stops bone loss and builds muscle in postmenopausal breast cancer survivors: a randomized, controlled trial

Targeted exercise training could reduce risk factors for fracture and obesity-related diseases that increase from breast cancer treatment, but has not been sufficiently tested. We hypothesized that progressive, moderate-intensity resistance + impact training would increase or maintain hip and spine bone mass, lean mass and fat mass and reduce bone turnover compared to controls who participated in a low-intensity, non-weight bearing stretching program. We conducted a randomized, controlled trial in 106 women with early stage breast cancer who were >1 year post-radiation and/or chemotherapy, ≥ 50 years of age at diagnosis and postmenopausal, free from osteoporosis and medications for bone loss, resistance and impact exercise naïve, and cleared to exercise by a physician. Women were randomly assigned to participate in 1 year of thrice-weekly progressive, moderate-intensity resistance + impact (jump) exercise or in a similar frequency and length control program of progressive, low-intensity stretching. Primary endpoints were bone mineral density (BMD; g/cm²) of the hip and spine and whole body bone-free lean and fat mass (kg) determined by DXA and biomarkers of bone turnover-serum osteocalcin (ng/ml) and urinary deoxypyrodiniline cross-links (nmol/mmolCr). Women in the resistance + impact training program preserved BMD at the lumbar spine (0.47 vs. -2.13%; P = 0.001) compared to controls. The resistance + impact group had a smaller increase in osteocalcin (7.0 vs. 27%, P = 0.03) and a larger decrease in deoxypyrodinoline (-49.9 vs. -32.6%, P = 0.06) than controls. Increases in lean mass from resistance + impact training were greatest among women currently taking aromatase inhibitors compared to controls not on this therapy (P = 0.01). Our combined program of resistance + impact exercise reduced risk factors for fracture among postmenopausal breast cancer survivors (BCS) and may be particularly relevant for BCS on aromatase inhibitors (AIs) because of the additional benefit of exercise on muscle mass that could reduce falls.

Dietary modification for women after breast cancer treatment: a narrative review

Diet is thought to account for about 25% of cancers in developed countries. It is well documented that the risks associated with both the breast cancer itself and its treatments are important for women previously treated for breast cancer. Women are at risk of recurrence of the primary disease and prone to develop treatment-induced co-morbidities, some of which are thought to be modified by diet. With a view to making dietary recommendations for the breast cancer patients we encounter in our clinical nursing research, we mined the literature to scope the most current robust evidence concerning the role of the diet in protecting women against the recurrence of breast cancer and its potential to ameliorate some of the longer-term morbidities associated with the disease. We found that the evidence about the role of the diet in breast cancer recurrence is largely inconclusive. However, drawing on international guidelines enabled us to make three definitive recommendations: women at risk of breast cancer recurrence, or who experience co-morbidities as a result of treatment, should limit their exposure to alcohol, moderate their nutritional intake so it does not contribute to post-menopausal weight gain, and should adhere to a balanced diet. Nursing education planned for breast cancer patients about dietary issues should ideally be individually tailored, based on a good understanding of the international recommendations and the evidence underpinning them.

Advances in management of bone disease in breast cancer

Breast cancer is the commonest malignancy diagnosed in women. Although there have been huge advances in treatment in recent years leading to excellent outlooks for many women, a significant number of patients are developing bone complications. This is often due to metastatic bone disease, which occurs in approximately 70% of women with advanced breast cancer. Additionally, accelerated bone loss and associated complications such as fractures may be a consequence of adjuvant treatment. Whatever the cause, cancer-induced bone disease can have potentially devastating clinical consequences for the patient, and results in a considerable economic burden to the health care provider. This review addresses the causes and sequelae of bone disease in both early and advanced breast cancer. The evidence for preserving bone health, both with traditional treatments such as bisphosphonates and newer agents, including antibody therapy is reviewed, with recommendations for current practice. Finally, we discuss the emerging potential role of bone-targeting therapies in preventing the development of metastatic disease.

Optimizing clinical benefits of bisphosphonates in cancer patients with bone metastases

Malignant bone disease is common in patients with advanced solid tumors or multiple myeloma. Bisphosphonates have been found to be important treatments for bone metastases. A positive benefit-risk ratio for bisphosphonates has been established, and ongoing clinical trials will determine whether individualized therapy is possible.

Bisphosphonates are important treatments for bone metastases. Considerations for optimizing the clinical benefits of bisphosphonates include efficacy, compliance, and safety. Several bisphosphonates are approved for clinical use; however, few have demonstrated broad efficacy in the oncology setting and been compared directly in clinical trials. Among patients with bone metastases from breast cancer, the efficacy of approved bisphosphonates was evaluated in a Cochrane review, showing a reduction in the risk of skeletal-related events (SREs) ranging from 8% to 41% compared with placebo. Between-trial comparisons are confounded by inconsistencies in trial design, SRE definition, and endpoint selection. Zoledronic acid has demonstrated clinical benefits beyond those of pamidronate in a head-to-head trial that included patients with breast cancer or multiple myeloma. Compliance and adherence also have effects on treatment efficacy. In a comparison study, the adherence rates with oral bisphosphonates were found to be significantly lower compared with those of intravenous bisphosphonates. The safety profiles of oral and intravenous bisphosphonates differ. Oral bisphosphonates are associated with gastrointestinal side effects, whereas intravenous bisphosphonates have dose- and infusion rate–dependent effects on renal function. Osteonecrosis of the jaw is an uncommon but serious event in patients receiving monthly intravenous bisphosphonates or denosumab. The incidence of this event can be reduced with careful oral hygiene. A positive benefit-risk ratio for bisphosphonates has been established, and ongoing clinical trials will determine whether individualized therapy is possible.

Guidelines for Osteoprotection in Breast Cancer Patients on an Aromatase Inhibitor

Postmenopausal women are at an increased risk of osteopenia and osteoporosis due to the physiologic loss of the bone protective effects of estrogen. Additionally, disease-related risk factors also contribute to the increased fracture risk. To further complicate matters, one of the most common and severe safety issues associated with cancer therapies for breast cancer patients is bone loss and the associated increased risk of fractures. These facts underscore the need to carefully monitor bone mineral density in patients with endocrine-responsive breast cancer, and to consider adjuvant therapy that may help manage and/or prevent bone loss and fracture. Aromatase inhibitors (AIs) are now in widespread clinical use for women with hormone receptor-positive breast cancer and have replaced tamoxifen as the gold standard of care. AIs target the estrogen biosynthetic pathway and deprive tumor cells of the growth-promoting effects of estrogen. These treatments provide significant benefit to patients in terms of improved disease-free and overall survival. Adversely, there is a concern of an increased risk of bone loss with prolonged therapy consequently leading to an increased fracture risk. This manuscript will review the recent literature pertaining to AI-associated bone loss and discuss suggested management and preventative approaches that may help patients remain on therapy to derive the most clinical benefits.

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.

[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.

Combining Src inhibitors and aromatase inhibitors: a novel strategy for overcoming endocrine resistance and bone loss

Aromatase inhibitors have largely replaced tamoxifen as the first-line treatment for postmenopausal women with metastatic, hormone receptor-positive (HR+) breast cancer. However, many patients develop clinical resistance with prolonged treatment, and oestrogen deprivation following aromatase inhibition can result in loss of bone mineral density. Furthermore, most patients with metastatic breast cancer develop bone metastases, and the resulting adverse skeletal-related events are a significant cause of patient morbidity. Src, a non-receptor tyrosine kinase, is a component of signalling pathways that regulate breast cancer cell proliferation, invasion and metastasis as well as osteoclast-mediated bone turnover. Preclinical evidence also suggests a role for Src in acquired endocrine resistance. As such, Src inhibition represents a logical strategy for the treatment of metastatic breast cancer. In vitro, combination therapy with Src inhibitors and endocrine agents, including aromatase inhibitors, has been shown to inhibit the proliferation and metastasis of both endocrine-responsive and endocrine-resistant breast cancer cell lines more effectively than either of the therapy alone. Src inhibition has also been shown to suppress osteoclast formation and activity. Combination therapy with aromatase inhibitors and Src inhibitors therefore represents a novel approach through which the development of both acquired resistance and bone pathology could be delayed. Data from clinical trials utilising such combinations will reveal if this strategy has the potential to improve patient outcomes.

The effect of risedronate on hip structural geometry in chemotherapy-induced postmenopausal women with or without use of aromatase inhibitors: a 2-year trial

INTRODUCTION

Osteoporosis is a major health problem for postmenopausal women. Adjuvant hormonal therapy with aromatase inhibitors (AIs) in postmenopausal breast cancer patients further worsens bone loss. Bisphosphonates are able to prevent AI-induced bone loss, but limited data exists on their effect on bone structure. Our objectives were to (1) examine the impact of AIs and no-AIs on hip structural geometry (HSA) of chemotherapy-induced postmenopausal women, and (2) determine if oral bisphosphonates could affect these changes.

METHODS

This is a sub-analysis of a 2-year double-blind randomized trial of 67 women with nonmetastatic breast cancer, newly postmenopausal following chemotherapy (up to 8 years), who were randomized to risedronate, 35 mg once weekly (RIS) and placebo (PBO). Many women changed their cancer therapy from a no-AI to an AI during the trial. Outcomes were changes in Beck's HSA-derived BMD and structural parameters.

RESULTS

Eighteen women did not receive adjuvant hormone therapy, while 41 women received other therapy and 8 received AIs at baseline distributed similarly between RIS and PBO. Women on AIs and PBO were found to have the lowest BMD and indices. RIS improved BMD and several HSA indices at the intertrochanteric site in women regardless of their hormonal therapy, but most improvement was observed in women who were not on AIs (all p< or =0.05 except buckling ratio). Changes at the narrow neck and femoral shaft were similar.

CONCLUSION

The use of AIs appears to lead to lower HSA-derived BMD and hip structural indices as compared to women on no or non-AI therapy in chemotherapy-induced postmenopausal breast cancer patients. Preventive therapy with once weekly oral risedronate maintains structural, skeletal integrity independently of the use of or type of adjuvant therapy.

New results from the use of bisphosphonates in cancer patients

PURPOSE OF REVIEW

Metastatic bone disease results from cancer-bone cell interactions in the bone marrow microenvironment rather than direct destruction by cancer cells. Additionally, cancer treatments may have adverse effects on bone health. Therefore, a clear rationale exists for bone-targeted therapies to prevent skeletal complications and potentially modify the underlying disease.

RECENT FINDINGS

Studies in metastatic disease have focused on refining treatment, largely through the use of bone metabolism markers. Use of bisphosphonates in early cancer has become increasingly important to prevent bone loss. Recent results, notably with zoledronic acid, indicate that bone mineral density can be maintained and increased bone turnover normalized. Bisphosphonates are potent inhibitors of bone osteolysis and may impede both the development of bone metastases and survival of dormant cells in the marrow microenvironment. Additionally, bisphosphonates may have direct effects on tumour cells, especially in combination with chemotherapy. Clinical trial results in breast cancer with clodronate were inconclusive, but recent data with zoledronic acid suggest that bisphosphonates may indeed modify the course of the disease.

SUMMARY

The roles of bisphosphonates in metastatic bone disease and the prevention of cancer treatment induced bone loss have been defined. However, results from ongoing metastasis prevention trials are required before routine adjuvant bisphosphonates can be recommended.

Prevention of osteoporosis after breast cancer

Breast cancer is a devastating illness but cure rates are increasing and as they do the secondary effects of breast cancer treatment on bone are becoming more prominent. Of particular concern is the increased fracture rates and dramatic bone loss seen in studies of patients undergoing therapy with aromatase inhibitors. Recently a UK Expert Group has drawn up guidelines for the prevention of bone loss. The main recommendations can be summarised as follows: Bone loss in women who experience a premature menopause due to treatment before the age of 45 or who are receiving ovarian suppression therapy is accelerated by the concomitant use of aromatase inhibitors. As they are at high risk of significant bone loss they should have a baseline dual energy X-ray absorptiometry (DXA) assessment of BMD. As randomised clinical trials in postmenopausal women indicate that bisphosphonates prevent the bone loss and accelerated bone turnover associated with aromatase inhibitor therapy their use as the main preventative therapy is recommended, along with a healthy lifestyle and adequate intake of calcium and vitamin D. Decisions on the initiation of treatment initiation should be based on a combination of risk factors for osteoporotic fracture and BMD levels. Due to the rate of bone loss associated with breast cancer treatments, and uncertainties about the interaction between aromatase inhibitor use and BMD for fracture risk, the thresholds for intervention have been set at a higher levels than generally recommended for postmenopausal osteoporosis.

Urinary lead exposure and breast cancer risk in a population-based case-control study

BACKGROUND

Lead is a toxic nonessential metal with widespread exposure starting in utero. Lead has been reclassified in 2004 by the International Agency for Research on Cancer Working Group from a "possible" to a "probable" human carcinogen. Lead may be a facilitative or permissive carcinogen, which means that lead may permit or augment the genotoxic effects of other exposures.

METHODS

This population-based study in Wisconsin gathered survey data and home-collected urine specimens from 246 women, ages 20 to 69 years, with incident invasive breast cancer identified from the Wisconsin state registry and 254 age-matched control subjects from population lists from September 2004 to February 2005. We measured urinary lead concentrations by inductively coupled plasma mass spectrometry, adjusted the values by specific gravity, and conducted interviews by telephone to obtain information on known and suspected breast cancer risk factors.

RESULTS

Women in the highest quartile of specific gravity-adjusted lead level (>/=1.10 mug/L) had twice the breast cancer risk of those in the lowest quartile (<0.42 mug/L; odds ratio, 1.99; 95% confidence interval, 1.1-3.6) after adjustment for established risk factors. Excluding women who were currently taking nonsteroidal aromatase inhibitors (n = 52), we did not observe any increased breast cancer risk after adjustment for established risk factors.

CONCLUSION

Our population-based case-control study suggests that lead exposure, as determined by specific gravity-adjusted urinary lead concentrations, is not associated with a significant increased risk for breast cancer.