A study of the effects of the aromatase inhibitors anastrozole and letrozole on bone metabolism in postmenopausal women with estrogen receptor-positive breast cancer

GnRH-a-based fertility-sparing treatment of atypical endometrial hyperplasia (AEH) and early endometrial carcinoma (EC) patients: a multicenter, open-label, randomized designed clinical trial protocol

BACKGROUND

Around 4% of women receive an endometrial cancer diagnosis before turning 40, mainly those without prior childbirth experience and a strong desire to preserve their ability to conceive. Consequently, for young patients diagnosed with atypical endometrial hyperplasia (AEH) or early endometrial carcinoma (EC), a fertility-preserving approach employing high-dose oral progesterone has been adopted. However, previous research has shown a notable relapse rate. Furthermore, the extended use of substantial oral progesterone doses may hinder ovarian function and raise the risk of weight gain, liver issues, blood clotting, and breast cancer. We previously assessed the clinical effectiveness and pregnancy outcomes of gonadotropin-releasing hormone agonist (GnRH-a) based re-treatment for women with EC and AEH who did not respond to oral progestin therapy but achieved favorable treatment results and reproductive outcomes.

METHODS

This study will be an open-label, two-armed, randomized, investigator-initiated multicenter trial evaluating the combination of GnRH-a with the levonorgestrel-releasing intrauterine system or the combination of GnRH-a with an aromatase inhibitor (comprising a subcutaneous GnRH-a injection every 4 weeks and daily oral letrozole 2.5 mg). A total of 226 participants will be randomly allocated to one of the two treatment groups in a 1:1 ratio. The primary objective is to determine the effectiveness of GnRH-a-based re-treatment in achieving a complete response (CR) at 24 weeks for patients with AEH or EC. Secondary objectives include assessing the pregnancy rate 12 weeks after treatment, as well as post-treatment pregnancy outcomes and the rate of recurrence.

ETHICS AND DISSEMINATION

The protocol received approval from the Institutional Review Board of Peking Union Medical College Hospital and from boards at five other institutions. The trial will adhere to the principles outlined in the World Medical Association's Declaration of Helsinki and follow Good Clinical Practice standards. The trial results will be disseminated through publication in a peer-reviewed journal.

CONCLUSIONS

Prospective evidence supporting conservative treatment for EC and AEH is limited. There is a need for new approaches that can achieve higher CR rates with fewer side effects. This trial will assess the effectiveness of GnRH-a-based fertility-sparing treatment in obese women and recurrent patients, offering a promising alternative for patients with EC and AEH.

TRIAL REGISTRATION NUMBER

Chinese Clinical Trial Registry ChiCTR2200067099. Registered on December 27, 2022.

Fat Body Mass and Vertebral Fracture Progression in Women With Breast Cancer

Importance

Women with early breast cancer (EBC) exposed to aromatase inhibitors (AIs) may experience fragility fractures despite treatment with bone-active drugs. Risk factors for fractures in patients receiving AIs and denosumab have not been explored to date.

Objectives

To evaluate whether an association exists between dual x-ray absorptiometry (DXA)-measured fat body mass (FBM) and vertebral fracture (VF) progression in postmenopausal women with EBC undergoing adjuvant therapy with AIs in combination with denosumab and to examine whether VF was associated with common risk factors for bone fracture and parameters of body composition other than FBM.

Design, Setting, and Participants

For this prospective, single-center, cohort study, 237 patients with EBC who were undergoing adjuvant treatment with AIs and denosumab (60 mg every 6 months) were enrolled at the Breast Unit of the ASST Spedali Civili of Brescia from September 2014 to June 2018. Data analysis was conducted in June 2022.

Exposure

Body composition parameters, bone mineral density, and morphometric VFs were assessed by DXA at study entry and after 18 months of therapy.

Main Outcomes and Measures

VF progression, defined as either new or worsening of preexisting VFs, between the 2 time points.

Results

Of the 237 patients enrolled (median [range] age, 61 [28-84] years), 17 (4.4%) reported VF progression. Univariable analysis found an association between VF progression and a history of clinical fractures (odds ratio [OR], 3.22; 95% CI, 1.19-8.74; P = .02), Fracture Risk Assessment Tool (FRAX) score for major fractures (OR, 4.42; 95% CI, 1.23-13.79; P = .04), percentage of FBM (OR, 6.04; 95% CI, 1.69-21.63; P = .006), and android fat (OR, 9.58; 95% CI, 1.17-78.21; P = .04) and an inverse association with appendicular lean mass index-FBM ratio (OR, 0.25, 95% CI, 0.08-0.82; P = .02). Multivariable analysis revealed percentage of FBM (OR, 5.41; 95% CI, 1.49-19.59; P = .01) and FRAX score (OR, 3.95; 95% CI, 1.09-14.39; P = .04) as independent variables associated with VF progression.

Conclusions and Relevance

The findings of this study suggest that baseline FBM is an independent factor for VF progression in patients with EBC treated with adjuvant AIs and denosumab. This observation is new and indicates that diet and exercise may synergize with denosumab in the management of bone health in this patient setting.

Denosumab effect on bone mineral density and urinary-NTX in breast cancer patients receiving aromatase inhibitors

INTRODUCTION

Aromatase inhibitors are used post-surgical intervention in postmenopausal patients with breast cancer. However, these drugs accelerate decline in bone mineral density (BMD), which is countered by use of denosumab, and the efficacy of the drug can be assessed by bone turnover markers. We investigated the effects of denosumab administration for 2 years on BMD and urinary N-telopeptide of type I collagen (u-NTX) levels in breast cancer patients treated with aromatase inhibitors.

MATERIALS AND METHODS

This was a single-center retrospective study. Postoperative hormone receptor-positive breast cancer patients with low T-scores biannually received denosumab from the time of initiation of aromatase inhibitor therapy for 2 years. BMD was measured every 6 months, and u-NTX levels were assessed after 1 month and thereby every 3 months.

RESULTS

The median patient age of the 55 patients included in this study was 69 (range: 51-90) years. BMD gradually increased in the lumbar spine and femoral neck and u-NTX levels were lowest at 3 months post-initiation of therapy. Patients were divided into two groups based on the change ratio of u-NTX 3 months post-denosumab administration. Of these, the group with higher change ratio showed a higher degree of BMD restoration in the lumbar spine and femoral neck 6 months post-denosumab treatment.

CONCLUSION

Denosumab increased BMD in patients treated with aromatase inhibitors. The u-NTX level decreased soon after start of denosumab treatment, and its change ratio is predictive of improvement in BMD.

Association of Fat Body Mass With Vertebral Fractures in Postmenopausal Women With Early Breast Cancer Undergoing Adjuvant Aromatase Inhibitor Therapy

IMPORTANCE

Aromatase inhibitors induce a profound depletion in serum estrogen levels. Postmenopausal obese women receiving aromatase inhibitor therapy may be at increased risk of bone fractures owing to the detrimental association of adiposity with bone quality and the loss of the protective effect of estrogens on bone mineral density.

OBJECTIVE

To determine whether fat body mass (FBM), as measured by dual-energy x-ray absorptiometry, is associated with vertebral fracture prevalence in postmenopausal women undergoing adjuvant aromatase inhibitor therapy for breast cancer.

DESIGN, SETTING, AND PARTICIPANTS

In this single-center, cross-sectional study, 556 postmenopausal women with early-stage breast cancer were consecutively enrolled from October 15, 2013, to June 30, 2018, and stratified according to whether they were aromatase inhibitor-naive or aromatase inhibitor-treated for at least 2 years. The database was locked on December 31, 2018, and data analysis was completed on February 28, 2019. Eligible patients in both groups had normal renal function, no metabolic diseases, and no previous or current treatment with antiosteoporotic drugs or glucocorticoids. Previous chemotherapy, but not tamoxifen, was permitted. Data were gathered once, at baseline.

MAIN OUTCOMES AND MEASURES

Vertebral fracture prevalence associated with FBM in aromatase inhibitor-naive and aromatase inhibitor-treated patients.

RESULTS

Of the 556 women enrolled, the mean age was 63.0 years (95% CI, 62.2-63.8 years). The 195 aromatase inhibitor-treated patients were older than the 361 aromatase inhibitor-naive patients (mean age, 66.1 vs 61.3 years; P < .001), had a higher body mass index (mean, 26.4 vs 25.3; P = .009), were less likely to engage in physical activity (65.3% vs 73.7%; P = .03), and were less likely to consume alcoholic beverages (68.4% vs 80.9%; P = .001). Among the aromatase inhibitor-naive patients, the vertebral fracture prevalence was higher in the subgroup with FBM below the median value than in those with high FBM, but the difference was not statistically significant (19.2% vs 13.3%; P = .13). Conversely, the proportion of vertebral fractures in the aromatase inhibitor-treated group was 20.0% in patients with low FBM vs 33.3% in patients with high FBM (P = .04). An opposite trend in the association of FBM with vertebral fracture prevalence according to aromatase inhibitor group was shown by multivariable analysis in the propensity score-matched sample: odds ratio, 0.38 (95% CI, 0.12-1.19) and 1.94 (95% CI, 0.67-5.64) in the aromatase inhibitor-naive and aromatase inhibitor-treated groups, respectively (odds ratio for the interaction, 5.77 [95% CI, 1.08-30.81]; P for interaction term = .03).

CONCLUSIONS AND RELEVANCE

Fat body mass may be associated with fragility-related fractures in patients with breast cancer who undergo aromatase inhibitor therapy. If these data are confirmed, obesity could be included in the algorithm for assessing fracture risk and selecting patients to receive bone resorption inhibitors.

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.

Bone remodeling and regulating biomarkers in women at the time of breast cancer diagnosis

PURPOSE

The majority of breast cancer patients receive endocrine therapy, including aromatase inhibitors known to cause increased bone resorption. Bone-related biomarkers at the time of breast cancer diagnosis may predict future risk of osteoporosis and fracture after endocrine therapy.

METHODS

In a large population of 2,401 female breast cancer patients who later underwent endocrine therapy, we measured two bone remodeling biomarkers, TRAP5b and BAP, and two bone regulating biomarkers, RANKL and OPG, in serum samples collected at the time of breast cancer diagnosis. We analyzed these biomarkers and their ratios with patients' demographic, lifestyle, clinical tumor characteristics, as well as bone health history.

RESULTS

The presence of bone metastases, prior bisphosphonate (BP) treatment, and blood collection after chemotherapy had a significant impact on biomarker levels. After excluding these cases and controlling for blood collection time, several factors, including age, race/ethnicity, body mass index, physical activity, alcohol consumption, smoking, and hormonal replacement therapy, were significantly associated with bone biomarkers, while vitamin D or calcium supplements and tumor characteristics were not. When prior BP users were included in, recent history of osteoporosis and fracture was also associated.

CONCLUSIONS

Our findings support further investigation of these biomarkers with bone health outcomes after endocrine therapy initiation in women with breast cancer.

TBS and BMD at the end of AI-therapy: A prospective study of the B-ABLE cohort

INTRODUCTION

Patients with breast cancer under aromatase inhibitor (AI) treatment often develop osteoporosis and their average bone loss rate is twice that of natural reduction during menopause, increasing fracture risk. As the current diagnostic technique based on bone mineral density (BMD) provides no information on bone quality, the Trabecular Bone Score (TBS) has been proposed to reflect bone microarchitecture status. The present study was designed to assess prospective changes in TBS and lumbar spine (LS) BMD in postmenopausal women with breast cancer at completion of AI treatment.

METHODS

B-ABLE is a prospective cohort of 735 women with breast cancer treated with AIs according to American Society of Clinical Oncology recommendations: 5years of AI starting within 6weeks post-surgery or 1month after the last cycle of chemotherapy (5y-AI group), or switching to an AI to complete 5-year therapy after 2-3years of tamoxifen (pTMX-AI group). Patients with osteoporosis were treated with oral bisphosphonates (BP). TBS and LS-BMD changes at completion of AI therapy were evaluated by Student t-test for paired samples. Pearson correlation coefficients were computed for correlations between LS-BMD and TBS.

RESULTS

AI treatment was completed by 277 women. Of these, 70 (25.3%) were allocated to BP therapy. The non-BP-treated patients (74.7%) showed significant decreases in TBS (-2.94% in pTMX-AI and -2.93% in 5y-AI groups) and in LS-BMD (-4.14% in pTMX-AI and -2.28% in 5y-AI groups) at the end of AI treatment. In BP-treated patients, TBS remained stable at the end of AI treatment, whereas LS-BMD showed significant increases (+2.30% in pTMX-AI and +5.33% in 5y-AI groups). Moderate associations between TBS and LS-BMD values at baseline and at the end of AI treatment (r=0.4; P<0.001) were observed. At the end of treatment, changes in spine BMD and TBS were weakly correlated (r=0.1, P<0.01).

CONCLUSIONS

AI therapy induces significant decreases in TBS, comparable to BMD loss. BP-treated patients maintained TBS values, whereas BMD increased. AI treatment leads to deterioration of bone microarchitecture, which seems to be attenuated by BP therapy.

Over-irradiation

Decreasing the burden of radiation therapy (RT) for breast cancer includes, next to complete omission, several ways to tailor the extent of RT. Possible options for this include lowering of the total dose, such as selective omission of the boost, hypofractionated RT to shorten the duration of treatment, the selective introduction of partial breast irradiation and anatomy based target volume contouring to decrease the size of the irradiated volumes. Elective regional nodal irradiation showed in several randomised trials and meta-analyses to significantly impact on local-regional control, disease-free survival, breast cancer mortality and overall survival. The generalisability of these results remains complex in the light of the decreasing use of axillary lymph node dissection, the use of more effective adjuvant systemic therapy, the increasing use of primary systemic therapy and continuously improving RT techniques. In general, the use of RT compensates for the decreasing extent of surgery to the breast and the axillary lymph nodes, eliminating residual tumour cells while maintaining better aesthetic and functional results. In some occasions, however, the indications for the extent of RT have to be based on limited pathological staging information. Research is ongoing to individualise RT more on the basis of biological factors including gene expression profiles. When considering age, treatment decisions should rather be based on biological instead of formal age. The aim of this review article is to put current evidence into the right perspective, and to search for an appropriate appreciation of the balance between efficacy and side effects of local-regional RT.

AI-related BMD variation in actual practice conditions: A prospective cohort study

The aim of the study was to evaluate the progression of bone mineral density (BMD) during 3 years of aromatase inhibitors (AI) therapy in actual practice conditions. This prospective, clinical cohort study of Barcelona-Aromatase induced Bone Loss in Early breast cancer (B-ABLE) assessed BMD changes during 3 years of AI treatment in women with breast cancer. Patients with osteoporosis (T score < -2.5 or T score ≤ -2.0) and a major risk factor and/or prevalent fragility fractures were treated with oral bisphosphonates (BPs). Of 685 women recruited, 179 (26.1%) received BP treatment. By the third year of AI therapy, this group exhibited increased BMD in the lumbar spine (LS; 2.59%) and femoral neck (FN; 2.50%), although the increase was significant only within the first year (LS: 1.99% and FN: 2.04%). Despite BP therapy, however, approximately 15% of these patients lost more than 3% of their baseline bone mass. At 3 years, patients without BP experienced BMD decreases in the LS (-3.10%) and FN (-2.79%). In this group, BMD changes occurred during the first (LS: -1.33% and FN: -1.25%), second (LS: -1.19% and FN: -0.82%), and third (LS: -0.57% and FN: -0.65%) years of AI treatment. Increased BMD (>3%) was observed in just 7.6% and 10.8% of these patients at the LS and FN, respectively. Our data confirm a clinically relevant bone loss associated with AI therapy amongst nonusers of preventative BPs. We further report on the importance of BMD monitoring as well as calcium and 25-hydroxy vitamin D supplementation in these patients.

Coadministrating luteolin minimizes the side effects of the aromatase inhibitor letrozole

Aromatase inhibitors (AIs) have been used as adjuvant therapeutic agents for breast cancer. Their adverse side effect on blood lipid is well documented. Some natural compounds have been shown to be potential AIs. In the present study, we compared the efficacy of the flavonoid luteolin to the clinically approved AI letrozole (Femara; Novartis Pharmaceuticals, East Hanover, NJ) in a cell and a mouse model. In the in vitro experimental results for aromatase inhibition, the Ki values of luteolin and letrozole were estimated to be 2.44 µM and 0.41 nM, respectively. Both letrozole and luteolin appeared to be competitive inhibitors. Subsequently, an animal model was used for the comparison. Aromatase-expressing MCF-7 cells were transplanted into ovariectomized athymic mice. Luteolin was given by mouth at 5, 20, and 50 mg/kg, whereas letrozole was administered by intravenous injection. Similar to letrozole, luteolin administration reduced plasma estrogen concentrations and suppressed the xenograft proliferation. The regulation of cell cycle and apoptotic proteins-such as a decrease in the expression of Bcl-xL, cyclin-A/D1/E, CDK2/4, and increase in that of Bax-was about the same in both treatments. The most significant disparity was on blood lipids. In contrast to letrozole, luteolin increased fasting plasma high-density lipoprotein concentrations and produced a desirable blood lipid profile. These results suggested that the flavonoid could be a coadjuvant therapeutic agent without impairing the action of AIs.

Procollagen assays in cancer

The synthesis rates of fibrillar collagens can be assessed in blood by measuring propeptides set free from corresponding procollagens before fiber formation. Type I collagen is the major component of the organic matrix of bone, but it is also found in other connective tissues. The serum concentration of the amino-terminal propeptide of type I procollagen, PINP, functions as a measure of type I collagen synthesis during normal bone turnover, but it is also released from bone metastases that involve an osteoblastic component. Type III collagen is a major constituent of soft tissues and the corresponding amino-terminal propeptide, PIIINP, reflects collagen synthesis. Circulating PIIINP tends to be affected by malignomas that grow in the peritoneal cavity or affect bone marrow. Many studies on procollagen markers in cancer have been cross-sectional or demonstrated treatment effects in patient groups. Markers that originate from bone turnover have wide reference intervals, but low biologic variability in individuals. Thus, they appear better suited for monitoring versus diagnostic purposes. There is still definite need for research on the use of procollagen markers in the followup of individual patients undergoing cancer treatment or being monitored after such treatment.

Preventive effect of risedronate on bone loss and frailty fractures in elderly women treated with anastrozole for early breast cancer

The aim of this study was to assess the effect of adjuvant anastrozole, alone or associated with risedronate, on BMD and bone fracture risk in women more than 70 years old with hormone receptor-positive early breast cancer (EBC). In a group of 51 elderly women (aged 76.4 ± 5.0 years) considered for adjuvant aromatase inhibitors for EBC, 24 patients with T-scores ≥ -2 and no prevalent fractures received anastrozole 1 mg/day (group A), and 27 patients with T-scores < -2, or with T-scores ≥ -2 and prevalent fractures (group B), received anastrozole (1 mg/day) plus risedronate (35 mg/week). Both groups received supplementation with 1 g calcium carbonate and 800 IU vitamin D per day. Differences in BMD and frailty fractures were evaluated after 1 and 2 years. In group A, significant decreases in BMD were observed in the lumbar spine (Δ BMD, -0.030 ± 0.04 g/cm², P < 0.05), femoral neck (Δ BMD, -0.029 ± 0.05 g/cm², P < 0.05), and trochanter (Δ BMD, -0.026 ± 0.03 g/cm², P < 0.01) after 2 years. The greatest percent reduction in height (Hpr) emerged in the thoracic spine (3.6 ± 2.4%, P < 0.01), although only one incident vertebral fracture was observed. In group B, BMD increased in the lumbar spine (Δ BMD, 0.038 ± 0.04, P < 0.001), although no significant changes were seen in the hip regions. The decline in Hpr was negligible (about 1%). No incident fractures were observed at follow-up. In conclusion, anastrozole treatment for EBC in elderly women seems to have only mild negative effects on the femoral bone. Risedronate makes the use of anastrozole safer, even for osteopenic or osteoporotic elderly patients.

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).

Measurement of aminoterminal propeptide of type I procollagen (PINP) in serum

The aminoterminal propeptide of type I procollagen (PINP) in serum is a sensitive indicator of the synthesis of type I collagen. Four assays are available for PINP, two of them (intact PINP assays) measure the intact propeptide and the other two (total PINP assays) also detect a smaller antigen in serum. In many clinical situations, these assays give similar information, but renal insufficiency increases the concentration of the smaller antigen, influencing both the apparent concentration of PINP and assay calibration. Serum PINP is mostly affected by changes in bone metabolism. In infants and children, the concentration is much higher than in adults. Serum PINP (s-PINP) is a useful indicator of disease activity in Paget's disease of bone, in bone metastases of osteoblastic nature, and in the follow-up of treatment of osteoporosis. The IFCC and IOF recently recommended the use of s-PINP as a reference marker for bone formation in studies concerning fracture risk assessment and treatment response.

Efficacy of zoledronic acid in postmenopausal Japanese women with early breast cancer receiving adjuvant letrozole: 12-month results

Aromatase inhibitor-associated bone loss has not been proved in the Japanese or Asian women. The aim of this study was to evaluate an upfront or delayed strategy of bone protection therapy with zoledronic acid administered at 4 mg every 6 months in postmenopausal Japanese women with early breast cancer to compare with results of the Z-FAST and ZO-FAST studies in western countries. Postmenopausal women with hormone receptor positive early breast cancer receiving adjuvant letrozole were randomly assigned to receive either upfront or delayed-start zoledronic acid (4 mg intravenously every 6 months). The delayed group received zoledronic acid when lumbar spine (L(2)-L(4)) bone mineral density (BMD) decreased to less than young adult mean -2.0SD or when a nontraumatic fracture occurred. The primary endpoint of this study was to compare the percent change in L(1)-L(4) BMD at 12 months between the groups. Secondary endpoints included percent changes in L(2)-L(4) and total hip (TH) BMD. The upfront and delayed groups included 94 and 95 patients, respectively. At 12 months, L(1)-L(4), L(2)-L(4), and TH BMD significantly decreased by 2.0, 2.4, and 2.4%, respectively, in the delayed group. L(1)-L(4) BMD was 4.9% higher in the upfront group than in the delayed group (95% CI 3.9-5.8%; p < 0.001). L(2)-L(4) BMD was 5.6% higher (95% CI 4.5-6.6%; p < 0.001), and TH BMD was 4.4% higher (95% CI 3.3-5.4%; p < 0.001). At 12 months, upfront zoledronic acid therapy prevented bone loss in postmenopausal Japanese women who were receiving adjuvant letrozole, confirming the Z-/ZO-FAST study results in western populations.

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

BACKGROUND

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Aromatase inhibitor-associated bone and musculoskeletal effects: new evidence defining etiology and strategies for management

Aromatase inhibitors are widely used as adjuvant therapy in postmenopausal women with hormone receptor-positive breast cancer. While the agents are associated with slightly improved survival outcomes when compared to tamoxifen alone, bone and musculoskeletal side effects are substantial and often lead to discontinuation of therapy. Ideally, the symptoms should be prevented or adequately treated. This review will focus on bone and musculoskeletal side effects of aromatase inhibitors, including osteoporosis, fractures, and arthralgias. Recent advances have been made in identifying potential mechanisms underlying these effects. Adequate management of symptoms may enhance patient adherence to therapy, thereby improving breast cancer-related outcomes.

Does anastrozole affect bone resorption similarly in early and late postmenopausal women?

The aim of this study was to determine whether the bone-resorption response to anastrozole differed according to initial patient age in postmenopausal women with breast cancer in a cross-sectional study. Second-morning void urines were collected for measurement of urinary cross-linked N-telopeptide of type I collagen (uNTx, corrected for creatinine and log-transformed) from postmenopausal women, 99 with breast cancer on anastrozole (ABC), 88 with newly diagnosed breast cancer (NDBC), and 137 community-dwelling healthy control (HC) women. Bone mineral density (BMD) was also measured at the lumbar spine (LS, L2-L4) and the femoral neck (FN) in the ABC group. uNTx (nanomole bone collagen equivalents/millimole creatinine) levels increased with age in HC subjects. In patients <70 years, anastrozole treatment led to a significant increase in uNTx compared with age-related HC subjects (1.74 vs. 1.55, P < 0.005). Patients >70 years showed no such increase compared to HC (1.72 vs. 1.69, nonsignificant); however, NDBC women >70 years had uNTx levels significantly lower than HC women (1.59 vs. 1.69, P < 0.05). There was no difference in uNTx levels above and below the age of 70 years in NDBC women (1.56 vs. 1.59, nonsignificant). ABC women were more likely to have a positive LS BMD z score than age-matched controls. Anastrozole treatment increases bone turnover more in younger postmenopausal women with breast cancer than in older women compared to healthy controls. Higher LS BMD in ABC patients may help protect against fracture.

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.

Management of anastrozole-induced bone loss in breast cancer patients with oral risedronate: results from the ARBI prospective clinical trial

INTRODUCTION

The aim of this multicenter, phase III, prospective open label clinical trial was to investigate the effect of risedronate (R) on bone mineral density (BMD) in postmenopausal, early breast cancer (BC) patients scheduled to receive anastrozole (A).

METHODS

Pre-treatment BMD of 213 patients with hormone receptor-positive BC was evaluated at lumbar spine (LS) and hip (HP). Patients were categorized according to their baseline BMD T-score as being at low, moderate and high risk of osteoporosis. Low risk patients received anastrozole only (A), moderate risk were randomized to anastrozole +/- risedronate (A+/-R) administration and high risk patients received anastrozole + risedronate (A+R). Anastrozole was given at a dosage of 1 mg/day while oral risedronate was given at 35 mg/week. BMD was then assessed at 12 and 24 months. All patients received daily supplements of calcium (1000 mg/day) and vitamin D (400 IU/day).

RESULTS

At 24 months, in the moderate risk group, treatment with A+R resulted in a significant increase in BMD at LS and HP compared to treatment with A only (5.7% v -1.5%, Wilcoxon test P = 0.006, and 1.6% v -3.9% Wilcoxon test P = 0.037, respectively), while no significant difference was found at 12 months; 24.3% of the patients moved to normal BMD region. In the high risk group, a significant increase for LS was detected both at 12 and 24 months (6.3% and 6.6%, P < 0.001) but not for HP; BMD in 14% of patients improved to the osteopenic region. In the low risk group, a significant decrease of BMD was detected at 12 months for LS and HP (-5.3% P < 0.001 and -2.4% P < 0.001, respectively,); at 24 months, a significant decrease of BMD was detected only for LS (-2.5%, P < 0.001). However, 22% of patients became osteopenic and only 4% became osteoporotic.

CONCLUSIONS

The addition of oral risedronate in post-menopausal breast cancer patients receiving anastrozole has a favorable effect on BMD. Patients with pre-treatment osteopenic to osteoporotic status should be treated with a combination of both therapies in order to avoid bone loss induced by aromatase inhibition. Patients with normal BMD before starting treatment with anastrozole have a very low risk to develop osteoporosis.