Zoledronic acid in the management of metastatic bone disease

Computed tomography density changes of bone metastases after concomitant denosumab

OBJECTIVE

To evaluate bone density changes at the level of normal trabecular bone and bone metastases (BMs) after denosumab (DM) treatment in oncologic patients.

MATERIALS AND METHODS

We retrospectively evaluated 31 consecutive adult patients with histologically confirmed solid tumors with at least one newly diagnosed bone metastatic lesion detected at CT. Patients received treatment with DM, 120 mg subcutaneous every 28 days for at least 6 months. Bone density was determined at the level of BMs and at the level of normal trabecular bone of lumbar vertebrae using a region of interest (ROI)-based approach.

RESULTS

A progressive increase in CT bone density was demonstrated at the level of normal trabecular bone at 6 months (18% ± 5%) and 12 months (23% ± 7%) after the treatment begins. BMs showed a significant increase in CT bone density (p < 0.05) as compared to baseline after 6 months (57% ± 15%) and 12 months (1.06 ± 0.25 times higher) after treatment.

CONCLUSION

We have found that long-term treatment with DM increases bone density progressively in oncologic patients. This effect can be observed not only at the level of secondary lesions but also at the level of apparently normal trabecular bone and is more pronounced for osteolytic metastases.

Current comprehensive understanding of denosumab (the RANKL neutralizing antibody) in the treatment of bone metastasis of malignant tumors, including pharmacological mechanism and clinical trials

Denosumab, a fully humanized monoclonal neutralizing antibody, inhibits activation of the RANK/RANKL/OPG signaling pathway through competitive binding with RANKL, thereby inhibiting osteoclast-mediated bone resorption. Denosumab inhibits bone loss; therefore, it is used to treat metabolic bone diseases (including postmenopausal osteoporosis, male osteoporosis, and glucocorticoid-induced osteoporosis), in clinical practice. Since then, multiple effects of denosumab have been discovered. A growing body of evidence suggests that denosumab has a variety of pharmacological activities and broad potential in clinical diseases such as osteoarthritis, bone tumors, and other autoimmune diseases. Currently, Denosumab is emerging as a treatment for patients with malignancy bone metastases, and it also shows direct or indirect anti-tumor effects in preclinical models and clinical applications. However, as an innovative drug, its clinical use for bone metastasis of malignant tumors is still insufficient, and its mechanism of action needs to be further investigated. This review systematically summarizes the pharmacological mechanism of action of denosumab and the current understanding and clinical practice of the use of denosumab for bone metastasis of malignant tumors to help clinicians and researchers deepen their understanding of denosumab.

Fracture Risk of Long Bone Metastases: A Review of Current and New Decision-Making Tools for Prophylactic Surgery

Simple Summary

Long bone metastases are frequently a pivotal point in the oncological history of patients. Weakening of the bone results in pathologic fractures that not only compromise patient function but also their survival. Therefore, the main issue for tumor boards remains timely assessment of the risk of fracture, as this is a key consideration in providing preventive surgery while also avoiding overtreatment. As the Mirels scoring system takes into account both the radiological and the clinical criteria, it has been used worldwide since the 1990s. However, due to increasing concern regarding the lack of accuracy, new thresholds have been defined for the identification of impending fractures that require prophylactic surgery, on the basis of axial cortical involvement and biomechanical models involving quantitative computed tomography. The aim of this review is to establish a state-of-the-art of the risk assessment of long bone metastases fractures, from simple radiologic scores to more complex multidimensional bone models, in order to define new decision-making tools.

Abstract

Long bone pathological fractures very much reflect bone metastases morbidity in many types of cancer. Bearing in mind that they not only compromise patient function but also survival, identifying impending fractures before the actual event is one of the main concerns for tumor boards. Indeed, timely prophylactic surgery has been demonstrated to increase patient quality of life as well as survival. However, early surgery for long bone metastases remains controversial as the current fracture risk assessment tools lack accuracy. This review first focuses on the gold standard Mirels rating system. It then explores other unique imaging thresholds such as axial or circumferential cortical involvement and the merits of nuclear imaging tools. To overcome the lack of specificity, other fracture prediction strategies have focused on biomechanical models based on quantitative computed tomography (CT): computed tomography rigidity analysis (CT-RA) and finite element analysis (CT-FEA). Despite their higher specificities in impending fracture assessment, their limited availability, along with a need for standardization, have limited their use in everyday practice. Currently, the prediction of long bone pathologic fractures is a multifactorial process. In this regard, machine learning could potentially be of value by taking into account clinical survival prediction as well as clinical and improved CT-RA/FEA data.

Bisphosphonate conjugation for bone specific drug targeting

Bones provide essential functions and are sites of unique biochemistry and specialized cells, but can also be sites of disease. The treatment of bone disorders and neoplasia has presented difficulties in the past, and improved delivery of drugs to bone remains an important goal for achieving effective treatments. Drug targeting strategies have improved drug localization to bone by taking advantage of the high mineral concentration unique to the bone hydroxyapatite matrix, as well as tissue-specific cell types. The bisphosphonate molecule class binds specifically to hydroxyapatite and inhibits osteoclast resorption of bone, providing direct treatment for degenerative bone disorders, and as emerging evidence suggests, cancer. These bone-binding molecules also provide the opportunity to deliver other drugs specifically to bone by bisphosphonate conjugation. Bisphosphonate bone-targeted therapies have been successful in treatment of osteoporosis, primary and metastatic neoplasms of the bone, and other bone disorders, as well as refining bone imaging. In this review, we focus upon the use of bisphosphonate conjugates with antineoplastic agents, and overview bisphosphonate based imaging agents, nanoparticles, and other drugs. We also discuss linker design potential and the current state of bisphosphonate conjugate research progress. Ongoing investigations continue to expand the possibilities for bone-targeted therapeutics and for extending their reach into clinical practice.

Bone Pain and Muscle Weakness in Cancer Patients

PURPOSE OF REVIEW

In this article, we will discuss the current understanding of bone pain and muscle weakness in cancer patients. We will describe the underlying physiology and mechanisms of cancer-induced bone pain (CIBP) and cancer-induced muscle wasting (CIMW), as well as current methods of diagnosis and treatment. We will discuss future therapies and research directions to help patients with these problems.

RECENT FINDINGS

There are several pharmacologic therapies that are currently in preclinical and clinical testing that appear to be promising adjuncts to current CIBP and CIMW therapies. Such therapies include resiniferitoxin, which is a targeted inhibitor of noceciptive nerve fibers, and selective androgen receptor modulators, which show promise in increasing lean mass. CIBP and CIMW are significant causes of morbidity in affected patients. Current management is mostly palliative; however, targeted therapies are poised to revolutionize how these problems are treated.

Uncertainty of current algorithm for bisphosphonate-related osteonecrosis of the jaw in population-based studies: a systematic review

To assess the relevance of previous epidemiologic studies on bisphosphonate-related osteonecrosis of the jaw (BRONJ), we first conducted a systematic review of large population-based observational studies and evaluated the validity of claims-based algorithms for the identification of BRONJ. Studies containing primary observational epidemiologic data regarding bisphosphonate (BP) exposure and outcomes of osteonecrosis of the jaw were systematically reviewed. Using surrogates for identifying potential BRONJ cases from a population-based hospital registry, validation was performed through medical chart review. Positive predictive value (PPV) was estimated for each diagnostic code and for the overall algorithm utilized. Various strategies to increase PPV were also performed. Seventeen studies were systematically reviewed and presented with variations in study quality as well as inconsistent findings. Moreover, there was a high level of methodological heterogeneity. A total of 1920 patients were identified through the ICD-10 algorithm with potential BRONJ, although only 109 cases were confirmed, corresponding to an overall PPV of 5.68% (95% confidence interval [CI] 4.68-6.81). Only K10.2 (inflammatory conditions of the jaw) exhibited a relatively high PPV of 26.18%, which increased to 74.47% after confinement to BP users. Other strategies to increase PPV value were not effective. Our findings showed that the overall PPV for BRONJ identification was very low, indicating low validity of the current algorithm and possible overestimation of ONJ occurrence. There is an urgent need to develop more reliable and specific operational definitions for the identification of BRONJ cases in large population databases. © 2016 American Society for Bone and Mineral Research.

Mechanism of Action, Pharmacokinetic and Pharmacodynamic Profile, and Clinical Applications of Nitrogen-containing Bisphosphonates

Nitrogen-containing bisphosphonates (nBPs) are bone-specific agents that inhibit farnesyl diphosphate synthase. nBPs’ strong affinity for bone, and not for other tissues, makes them potent inhibitors of bone resorption and bone remodeling activity, with limited potential for side-effects in non-skeletal tissues. Five nBPs are currently approved in the United States. The primary indications are for treatment of osteoporosis (alendronate, ibandronate, and risedronate) and treatment/prevention of skeletal-related events (SREs) in multiple myeloma and breast and prostate cancer patients (ibandronate, pamidronate, and zoledronic acid). nBPs are the most efficacious drugs available for these diseases, reducing osteoporotic fracture risk by 50–60% in persons with low bone mass or prior osteoporotic fracture, and SREs by one-third in cancer patients. The absorbed nBP dose for cancer patients is from seven to ten times that in osteoporosis patients. nBPs are unique in that they first exert profound pharmacodynamic effects long after their blood levels reach zero. Current pharmacokinetic studies indicate that approximately half of any nBP dose reaches the skeleton, with an early half-life of ten days, and a terminal half-life of about ten years. Practical study design limitations and theoretical considerations suggest that both the half-life and the amount of nBP retained in the skeletons of patients on long-term nBP therapy are substantially overestimated by extrapolation directly from current pharmacokinetic data. In fact, the amount of nBP being released from skeletal tissues of long-term-treated patients, particularly in osteoporosis patients, becomes insufficient to maintain full pharmacodynamic efficacy relatively soon after dosing is interrupted.

Management of differentiated thyroid carcinoma with bone metastasis: a case report and review of the Chinese literature

Differentiated thyroid carcinoma (DTC) is a common malignancy. The general treatments are thyroidectomy of the affected lobe along with lymphadenectomy. However, bone metastasis is rare in DTC compared with other malignancies and the management of metastasis foci is still controversial. Here we present a case of follicular thyroid carcinoma with the 6th cervical vertebra body metastasis successfully treated by total thyroidectomy, cervical corpectomy, and internal fixation, followed by hormone replacement therapy and radioiodine therapy. Eleven additional patients diagnosed as thyroid carcinoma with bone metastasis collected from Chinese literature between January 1996 and December 2013 were also reviewed. The mean age of the 12 patients at presentation was (53.9±9.2) years (rang, 42-72 years) and the male to female ratio was 1:2. Nine cases received total/near-total thyroidectomy or lobectomy while the other three patients refused for personal reasons. The interventions for bone metastasis were one-stage operation (9/12), I(131) adjuvant therapy (3/12), chemotherapy (1/12), and no intervention (1/12). During the follow-up, two patients died of metastatic carcinoma recurrence, one died of multiple organ metastasis, and one with an unknown reason. We conclude that the management of thyroid carcinoma with bone metastasis needs multidisciplinary cooperation. Surgical resection is still the first choice for cure, while the combined one-stage operation on the primary and metastatic sites followed by hormone replacement therapy and radioiodine therapy is an applicable treatment.

Painful boney metastases

Boney metastasis may lead to terrible suffering from debilitating pain. The most likely malignancies that spread to bone are prostate, breast, and lung. Painful osseous metastases are typically associated with multiple episodes of breakthrough pain which may occur with activities of daily living, weight bearing, lifting, coughing, and sneezing. Almost half of these breakthrough pain episodes are rapid in onset and short in duration and 44% of episodes are unpredictable. Treatment strategies include: analgesic approaches with "triple opioid therapy", bisphosphonates, chemotherapeutic agents, hormonal therapy, interventional and surgical approaches, steroids, radiation (external beam radiation, radiopharmaceuticals), ablative techniques (radiofrequency ablation, cryoablation), and intrathecal analgesics.

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

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

Early surgical laser-assisted management of bisphosphonate-related osteonecrosis of the jaws (BRONJ): a retrospective analysis of 101 treated sites with long-term follow-up

BACKGROUND DATA

The management of bisphosphonate-related osteonecrosis of the jaws (BRONJ) is still controversial.

OBJECTIVE

The purpose of this study was to compare surgical and nonsurgical approaches to the treatment of BRONJ and the possible usefulness of Nd:YAG and Er:YAG lasers.

METHODS

One hundred and twenty-eight patients (33 males, 95 females; 52 with diagnosis of multiple myeloma, 53 with diagnosis of bone metastasis, and 23 with diagnosis of osteoporosis) affected by BRONJ were evaluated at the Unit of Oral Pathology and Medicine and Laser-Assisted Surgery of the University of Parma, Italy, between January 2004 and July 2009. Overall number of BRONJ sites was 151, and number of treated sites was 101. In order to assess the efficacy of different treatments, sites were subclassified as follows: Group 1 (G1): 12 sites treated with medical therapy; Group 2 (G2): 27 sites treated with medical therapy associated with low level laser therapy (LLLT); Group 3 (G3): 17 sites treated with a combination of medical and surgical therapy; Group 4 (G4): 45 sites treated with a combination of medical therapy, surgical (including laser-assisted) therapy, and LLLT. Outcome of treatment was assessed using the staging system proposed by Ruggiero et al. Transition from a higher stage to a lower one for at least 6 months was considered as clinical improvement and suggestive of a successful treatment.

RESULTS

Clinical improvement was achieved in 3 out of 12 (25%) BRONJ sites in G1. Sites if G2 with an improvement were 18 out of 27 (66%). Nine out 17 BRONJ sites (53%) in G3 had a transition to a lower stage after treatment. For sites in G4, a clinical improvement was recorded in 40 out of 45 cases (89%).

CONCLUSIONS

In our experience, the percentage of success obtained with a combined approach based on medical therapy, surgical (including laser-assisted) therapy, and LLLT (G4) is significantly higher than the percentage of improvement obtained in G1, G2, and G3.

Bisphosphonate anticancer activity

Bone metastases have a major impact on morbidity and on mortality in cancer patients. Despite its clinical relevance, metastasis remains the most poorly elucidated aspect of carcinogenesis. Different pathways or molecules such as RANK/RANKL/OPG, cathepsin K, endothelin-1, Wnt/DKK1 and Src have recently emerged as potential targets, and preclinical and clinical trials are now underway. The results from clinical trials indicate the importance of treating and preventing bone metastases in many different cancer populations.

Zoledronic acid in the treatment of bone metastases from differentiated thyroid carcinoma

BACKGROUND

Currently bisphosphonates are often administered to patients with osteolytic bone metastases from several neoplasms. Based on favorable experience in other cancers with bone metastases and the lack of effective treatment, we started to use zoledronic acid (ZA), a recently developed synthetic bisphosphonate drug, in the treatment of this disease. In the present study, we retrospectively evaluated the efficacy of ZA for bone metastases from differentiated thyroid carcinoma.

METHODS

The study consisted of 50 patients with bone metastases from differentiated thyroid carcinoma treated at the Cancer Institute Hospital of Tokyo between 1976 and 2008. Among them, 28 patients who did not undergo bisphosphonate therapy were defined as group A and 22 patients who received ZA therapy were defined as group B. The primary efficacy endpoint for ZA treatment was the reduction in the percentage of patients who developed skeletal-related events (SREs), including bone fracture, spinal cord compression, and hypercalcemia. A secondary endpoint was the interval between a presentation of bone metastases and appearance of SREs.

RESULTS

SREs occurred in significantly lower frequency in group B (3 of 22 patients, 14%) than group A (14 of 28 patients, 50%) (p = 0.007). The use of ZA significantly retarded the onset of the first SRE (p = 0.04). Two group-B patients developed bisphosphonate-related osteonecrosis of the jaw.

CONCLUSION

Treatment with ZA was effective in reducing SREs or delaying their appearance in patients with bone metastases from differentiated thyroid carcinoma.

Dose-Fractionation Schedules for Radiotherapy of Bone Metastases

BACKGROUND: Bone metastases are common in breast cancer patients. Radiotherapy is safe and effective. This review aimes to contribute to the definition of the appropriate radiation regimens for different endpoints. MATERIAL AND METHODS: Information was compiled by searching PubMed and MEDLINE databases including early-release publications. When possible, primary sources were quoted. Full articles were obtained. References were checked for additional material when appropriate. RESULTS: Randomized trials and meta-analyses demonstrated that single-fraction radiotherapy with 1 × 8 Gy is as effective for pain relief as multi-fraction regimens such as 5 × 4 Gy or 10 × 3 Gy. Re-irradiation for recurrent pain is required more often after single-fraction radiotherapy. Re-irradiation with another single fraction is safe and effective. Multi-fraction long-course radiotherapy such as 10 × 3 Gy leads to better re-calcification and better local control of metastatic spinal cord compression (MSCC). Because both re-calcification and MSCC recurrences occur only several months after radiotherapy, long-course radiotherapy is particularly appropriate for patients with a favorable survival prognosis. CONCLUSIONS: For uncomplicated painful bone metastases, single-fraction radiotherapy with 1 × 8 Gy may be considered the standard regimen. If re-calcification is a major goal, longer-course radiotherapy (i.e. 10 × 3 Gy) should be used. For MSCC, 10 × 3 Gy is preferable for patients with a favorable survival prognosis.

Prognostic factors and the therapeutic strategy for patients with bone metastasis from differentiated thyroid carcinoma

BACKGROUND

The treatment of bone metastasis in association with thyroid cancer represents a difficult challenge. Given the paucity of patients with bone metastasis and the difficulty of treating this disease, few studies have investigated the clinical features and prognostic factors of bone metastasis from differentiated thyroid cancer.

METHODS

During the 31-year-period from 1976 to 2006, a total of 1,398 patients underwent initial thyroidectomy at Cancer Institute Hospital for differentiated thyroid carcinomas, including standard papillary thyroid carcinoma, papillary microcarcinoma (primary tumor diameter < or =1.0 cm), and follicular thyroid carcinoma. Among these, 25 (2%) patients displayed bone metastasis at initial presentation (synchronous) and 27 patients showed bone metastasis during follow-up (metachronous). The records for these 52 patients were reviewed retrospectively to identify prognostic factors and analyze treatment strategies.

RESULTS

Univariate analysis for disease-specific survival indicated metachronous bone metastasis and the presence of distant metastasis at sites other than bone as indicators of significantly worse prognosis. The type of cancer (papillary thyroid carcinoma versus follicular thyroid carcinoma) was not a significant indicator of prognosis; however, patients with papillary microcarcinoma showed significantly worse survival than patients with standard papillary and follicular thyroid carcinoma. A significant survival advantage was observed among patients who underwent radioactive iodine therapy, and better prognosis seemed to be obtained with greater doses of radioactive iodine. Operative resection of metastatic bone lesions also seemed to be associated with better prognosis. A multivariate analysis for disease-specific survival identified the coexistence of distant metastasis at sites other than bone as the only independent variable indicative of poor prognosis.

CONCLUSION

In the absence of definitive, effective treatments for this disease, radioactive iodine therapy combined with resection of bone metastasis, wherever possible, seems to represent the most potent therapy available. Although bone metastasis is a strong sign of poor prognosis, early detection and administration of appropriate therapy using radioactive iodine seems likely to improve the survival rate and quality of life in patients with bone metastasis from differentiated thyroid carcinoma.

Optimal treatment strategies in postmenopausal women with hormone-receptor-positive and HER2-negative metastatic breast cancer

Metastatic breast cancer (MBC) is unfortunately still considered incurable; treatment aims to prolong progression-free and overall survival, relieve disease symptoms, and maintain quality of life. Treatment can include endocrine therapy, radiotherapy, chemotherapy, bisphosphonates, and/or targeted therapy; which is used depends on the characteristics of the disease [e.g., hormone receptor status, disease site(s), and response to previous treatment] and the patient (age, comorbidity, and personal preferences). For most patients with hormone-receptor-positive tumors, the first choice of treatment is further endocrine therapy, but endocrine resistance is a common problem in advanced disease. Several novel anticancer agents have been developed with the aim of overcoming endocrine resistance, many of which target intracellular signaling pathways implicated in disease progression or resistance. Among these, inhibitors of growth factor receptor tyrosine kinases and of mammalian target of rapamycin have shown the most promise in clinical trials. Chemotherapy is the cornerstone of MBC treatment in most women. Important considerations when choosing chemotherapy include the choice of agents, and whether to use single-agent or combination therapy. Anthracyclines are one of the most active cytotoxic agents currently used for the treatment of breast cancer, and for many women, further anthracycline therapy at progression or relapse would be the preferred option. However, lifetime exposure to anthracyclines is limited by cumulative cardiotoxicity, which often prevents rechallenge in later lines of therapy. Newer anthracycline formulations have been developed with lower cardiotoxicity than the conventional anthracycline doxorubicin, but these agents still impair cardiac function, and have maximum recommended lifetime doses. Recently, the concomitant use of cardioprotective agents, such as dexrazoxane, has emerged as an effective approach to reducing the cardiotoxic effects of anthracyclines, thus permitting retreatment. Bisphosphonates, which are not associated with the acute toxicities of cytotoxic chemotherapy drugs, are the established standard of care for patients with metastatic bone disease, and have greatly improved outcomes over the last decade. The search is ongoing for novel agents that will, hopefully, bring a cure closer to reality.

Samarium lexidronam (153Sm-EDTMP): skeletal radiation for osteoblastic bone metastases and osteosarcoma

Radiation therapy can be an effective means to treat bone metastases, which occur in more than 50% of cancer patients. (153)Samarium lexidronam ((153)Sm-EDTMP; Quadramet, Cytogen) is a radiopharmaceutical designed for deposition into bone metastases. Bone scans can identify patients that may benefit from targeted radiation therapy with (153)Sm-EDTMP. As an unsealed source of radiation therapy, (153)Sm-EDTMP is simple to administer: 1 mCi/kg is given in a similar fashion to a bone scan injection ((99m)Tc-MDP bone scan injection is given at 0.2-0.35 mCi/kg. Therefore, both are administered intravenously. However, the radiation-absorbed dose and radiopharmaceutical energy are different). Nevertheless, despite simplicity of administration, (153)Sm-EDTMP is underutilized for improving cancer pain in the skeleton. Repeated cycles and combined treatment with other modalities such as bisphosphonates, chemotherapy and/or external beam radiation are possible. (153)Sm-EDTMP combined with bisphosphonates, chemotherapy and/or radiation may provide better palliation of bone metastases and also in bone-forming tumors (osteosarcoma). Encouraging experience using high-dose (153)Sm-EDTMP for total marrow irradiation in hematologic malignancies involving the bones (e.g., myeloma or acute leukemia) is also reviewed.

Evaluating distant metastases in breast cancer: from biology to outcomes

There is an urgent need to understand distant metastases in breast cancer as they are the most lethal form of recurrence and a major cause of mortality in patients. Some predictors for distant metastases, including nodal status, tumor grade, and hormonal status, are useful in identifying patients at increased risk for distant metastases. Adjuvant endocrine therapy has been the treatment of choice for postmenopausal women with hormone-sensitive breast cancer, and some therapies have shown significant reductions in the risk of distant metastases. Skeletal metastases in breast cancer are treated with bisphosphonates with a certain level of success. With more new agents undergoing clinical trials, a thorough review of the specific and long-term safety of these agents is essential, as is a better understanding of the deterioration in the quality of life and cost concerns of patients who develop distant metastases. Gene-expression profiling is a new entrant in the field of distant metastases diagnosis, which is largely successful in defining gene signatures that predict the development of distant metastases. This review will discuss the biology and the impact of distant metastases on outcomes for patients with breast cancer; it also encompasses the current status, emerging focus, and future perspectives in treatment of skeletal metastases in patients with breast cancer.

New developments of aminobisphosphonates: the double face of Janus

BACKGROUND

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

DESIGN

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

CONCLUSIONS

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

Circulating cathepsin K and cystatin C in patients with cancer related bone disease: clinical and therapeutic implications

The clinical significance of serum cathepsin K and cystatin C was assessed in patients with breast cancer (BCa) or prostate cancer (PCa) with confined disease (M0) or bone metastasis (BM). Cathepsin K and cystatin C circulating levels were determined by ELISAs in 63 cancer patients, in 35 patients with nonmalignant diseases and in 42 healthy blood donors (control group). In BCa patients, cathepsin K serum levels were significantly lower than in sex matched control group (HS; p=0.0008) or in patients with primary osteoporosis (OP; p=0.0009). On the contrary, cystatin C levels were significantly higher in BCa patients than in HS (p=0.0001) or OP (p=0.017). In PCa patients, cathepsin K concentrations did not significantly differ from those measured in sex matched HS or in patients with benign prostatic hyperplasia (BPH). Conversely, cystatin C was more elevated in cancer patients than in controls (p=0.0001) or BPH patients (p=0.0078). Furthermore, in PCa patients, a positive correlation was observed between cystatin C and cathepsin K (r(S)=0.34; p=0.047). No further relationship was highlighted between these molecules and the clinicobiological parameters of BCa or PCa progression including the number of bone lesions. Moreover, ROC curve analysis showed a poor diagnostic performance of cathepsin K and cystatin C in the detection of BM patients. Interestingly, the administration of zoledronic acid (ZA), a bisphosphonate derivative endowed with a potent antiosteoclastic activity, induced in BM patients a marked increase of cathepsin K and cystatin C serum levels compared to baseline values. However, this phenomenon was statistically significant only in the PCa group. In conclusion Cystatin C and cathepsin K may be regarded as possible markers to monitor the therapeutic response to bisphosphonate treatments. Nevertheless, their clinical value as specific gauges of skeletal metastasis remains questionable.