Bone Quality and Fractures in Women With Osteoporosis Treated With Bisphosphonates for 1 to 14 Years

Recent Advances in Minimally Invasive Management of Osteolytic Periacetabular Skeletal Metastases

Painful skeletal osteolytic metastases, impending pathological fractures, and nondisplaced fractures present as a devastating clinical problem in advanced stage cancer patients. Open surgical approaches provide excellent mechanical stabilization but are often associated with high complication rates and slow recovery times. Percutaneous minimally invasive interventions have arisen as a pragmatic and logical treatment option for patients with late-stage cancer in whom open surgery may be contraindicated. These percutaneous interventions minimize soft tissue dissection, allow for the immediate initiation or resumption of chemotherapies, and present with fewer complications. This review provides the most up-to-date technical and conceptual framework for the minimally invasive management of osseous metastases with particular focus on periacetabular lesions. Fundamental topics discussed are as follows: (1) pathogenesis of cancer-induced bone loss and the importance of local cytoreduction to restore bone quality, (2) anatomy and biomechanics of the acetabulum as a weight-bearing zone, (3) overview of ablation options and cement/screw techniques, and (4) combinatorial approaches. Future studies should include additional studies with more long-term follow-up to better assess mechanical durability of minimally invasive interventions. An acetabulum-specific functional and pain scoring framework should be adopted to allow for better cross-study comparison.

Trabecular bone microcrack accumulation in patients treated with bisphosphonates for durations up to 16 years

This study quantified the length, number, and density of microcracks in bone from patients treated with bisphosphonates as a function of duration. Anterior iliac crest bone samples from 51 osteoporotic Caucasian females continuously treated with oral bisphosphonates for 1-16 years were obtained by bone biopsy. Samples were histologically processed and analyzed for bone area, microcrack number, and microcrack length. The analyses used statistical modeling and considered patient age, bone mineral density, bone volume/total volume, trabecular thickness, and bone turnover as potential covariates. Microcrack density (number of microcracks/total examined bone area) was linearly related (p = 0.018) to bisphosphonate treatment duration. None of the analyzed covariates contributed significantly to the observed relationship between microcrack density and bisphosphonate treatment duration. Observed increases in microcrack density with increasing bisphosphonate treatment duration is important because increasing levels of microcracks may not only affect bone remodeling but also reduce elastic modulus and are suspected to adversely affect other mechanical properties that may influence fracture risk. The present findings add to our prior results showing changes in bone material properties and modulus with bisphosphonate treatment duration and thereby provide a more comprehensive assessment of the relationship between bisphosphonate treatment duration and bone quality. Statement of Clinical Significance: The present findings provide information guiding clinical use of oral bisphosphonates for post-menopausal osteoporosis therapy.

Management of bone loss due to endocrine therapy during cancer treatment

Bone modifying agents BMAs (oral and IV bisphosphonates, denosumab) are used to treat bone loss due to endocrine therapy in patients with hormone receptor positive (HR +) early breast cancer and non-metastatic prostate cancer (NMPC). Timely initiation of appropriate sequential therapy is imperative to reduce cancer treatment-induced bone loss (CTIBL). This narrative review summarizes current literature regarding management of CTIBL in HR + early breast cancer and NMPC patients. Risk factors for fragility fractures, screening strategies, optimal timing for the treatment, dosing/duration of therapy, and post treatment monitoring have not been clearly defined in HR + early breast and NMPC patients receiving endocrine therapy. This review aims to discuss the utility of fracture risk assessment (FRAX) tool for the prevention and management of CTIBL, osteoanabolic therapy for imminent fracture risk reduction, and sequential therapy options. Using predefined terms, PubMed, MEDLINE, and Google Scholar were searched for studies on CTIBL in HR + breast and NMPC patients. We included randomized clinical trials, meta-analysis, evidence-based reviews, observational studies, and clinical practice guidelines. Fracture risk assessment tools (FRAX) guide therapy for osteoporosis in patients with early HR + breast cancer and NMPC. BMAs to prevent bone loss should be initiated at higher T-score than recommended by FRAX in premenopausal HR + breast cancer patients with chemotherapy-induced ovarian failure, oophorectomy and gonadotropin releasing hormone (GnRH) therapy, post-menopausal women with HR + breast cancer receiving aromatase inhibitor therapy, and NMPC patients with androgen deprivation therapy. Sequential therapy with osteoanabolic agents as first line treatment offers a potential therapeutic strategy in patients with high imminent fracture risk. Due to limited data in cancer patients regarding management of osteoporosis, a dosing schedule similar to osteoporosis is considered appropriate. Risk stratification to identify vulnerable patient population, choosing the appropriate sequential therapy, and close monitoring of patients at the risk of bone loss can potentially reduce the mortality, morbidity, and health care cost related to CTIBL.

Osteoporosis and Fragility Fractures: currently available pharmacological options and future directions

Osteoporosis is a systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fracture. The average lifetime risk of a 50-year-old woman to suffer a fracture of the spine, hip, proximal humerus, or distal forearm has been estimated at close to 50%. In general, pharmacological treatment is recommended in patients who suffered a fragility fracture because their risk of suffering a subsequent fracture is increased dramatically. Therefore, many guidelines recommend pharmacological treatment in patients without a prevalent fracture if their fracture probability is comparable to or higher than that of a person of the same age with a prevalent fracture. The present review aims to highlight currently available pharmacological treatment options and their antifracture efficacy including safety aspects. Drug classes discussed comprise bisphosphonates, selective estrogen receptor modulators, parathyroid hormone peptides and derivatives, humanized monoclonal antibodies, and estrogens and gestagens and their combinations. Furthermore, a brief glimpse is provided into a potentially promising treatment option that involves mesenchymal stem cells.

Low Turnover Renal Osteodystrophy With Abnormal Bone Quality and Vascular Calcification in Patients With Mild-to-Moderate CKD

Introduction

Limited information is available on renal osteodystrophy (ROD) and vascular calcification (VC) during early chronic kidney disease (CKD). This study was designed to evaluate ROD and VC in 32 patients with CKD stages II to IV.

Methods

Patients underwent dual-energy X-ray absorptiometry (DXA) for assessment of bone mineral density (BMD) and trabecular bone score (TBS), thoracic computed tomography for VC scoring using the Agatston method, and anterior iliac crest bone biopsy for mineralized bone histology, histomorphometry, and Fourier transform infrared spectroscopy (FTIR). Classical and novel bone markers were determined in the blood.

Results

Mean estimated glomerular filtration rate (eGFR) was 44 ± 16 ml/min per 1.73 m2. Of the patients, 84% had low bone turnover. In Whites, eGFR correlated negatively with the turnover parameter activation frequency (Ac.f) (r -0.48, P = 0.019) and with parameters of bone formation. Most patients had VC (>80%) which correlated positively with levels of phosphorus, c-terminal fibroblast growth factor-23, and activin. Aortic calcifications (ACs) correlated negatively with bone formation rate (BFR) and Ac.f (rho -0.62, -0.61, P < 0.001). TBS correlated negatively with coronary calcification (rho -0.42, P = 0.019) and AC (rho -0.57, P = 0.001). These relationships remained after adjustment of age. The mineral-to-matrix ratio, an FTIR metric reflecting bone quality, was negatively related to Ac.f and positively related to AC.

Conclusion

Low bone turnover and VC are predominant in early stages of CKD. This is the first study demonstrating mineral abnormalities indicating reduced bone quality in these stages of CKD.