Frequency and risk factors associated with osteonecrosis of the jaw in cancer patients treated with intravenous bisphosphonates

Evaluation of dental implants as a risk factor for the development of bisphosphonate-related osteonecrosis of the jaw in breast cancer patients

It remains unclear whether dental implants are a risk factor for the development of bisphosphonate-related osteonecrosis of the jaw (BRONJ). We retrospectively evaluated the status of dental implants in patients given intravenous bisphosphonates (BPs) in a breast cancer cohort to elucidate the risk for BRONJ at the implant site. We established a BRONJ oral monitoring program for 247 breast cancer patients given intravenous BP in our institution. The 3-year cumulative incidence rate was determined. The systemic and local risk factors of 44 patients who completed comprehensive oral examinations were evaluated by logistic regression analysis. The 3-year cumulative incidence rate of the 247 patients was 0.074 % (8/247, 95 % CI 0.0081-0.014). In the 44 orally examined patients, 6 (13.6 %: 6/44) had dental implants. Of these 6 patients, 1 developed BRONJ at the implant site. There were no significant differences in the age, total BP treatment period, number of residual teeth, time of regular oral monitoring, oral hygiene level, or dental implant insertion. Although a case of ONJ was identified, dental implants which were inserted before intravenous BP administration were not a risk factor for the development of ONJ in breast cancer patients.

Standardized classification unsuitable for spontaneous reporting: the example of osteonecrosis of the jaw

OBJECTIVE

This study assessed the impact of using a standardized definition of bisphosphonate-related osteonecrosis of the jaw (BRONJ) in the analysis of a spontaneous reporting database.

METHODS

All notifications of osteonecrosis of the jaw (ONJ) in the French National Pharmacovigilance Database as of 31 December 2013 were analyzed. First, we considered all reports of ONJ with bisphosphonates as BRONJ. Second, we applied the 2014 definition of BRONJ from the American Association of Oral and Maxillofacial Surgeons (AAOMS), retaining only bisphosphonates as antiresorptive medication. In the absence of any one of these criteria, or missing data, cases were not considered as BRONJ.

RESULTS

The first analysis found 158 cases of ONJ, among which 153 were associated with bisphosphonate use. The second analysis identified only 43 cases of BRONJ (28.1%).

CONCLUSION

The definition of BRONJ as laid down by the AAOMS is not suitable for use in spontaneous reporting database. The use of the AAOMS definition alone should be avoided, as it leads to the exclusion of over 70% of cases. When cases of ONJ are identified, all results should be presented including confirmed and excluded cases.

Is administration of trastuzumab an independent risk factor for developing osteonecrosis of the jaw among metastatic breast cancer patients under zoledronic acid treatment?

One of the most important adverse effects of zoledronic acid (ZA) is osteonecrosis of the jaw (ONJ). In previous literature, several risk factors have been identified in the development of ONJ. In this study, we aimed to determine the role of trastuzumab, an antiangiogenic agent, as an independent risk factor for the development of this serious side effect.Our study included 97 patients (mean age: 54 ± 10 years) with breast cancer, recorded in the archives of the Istanbul Florence Nightingale Breast Study Group, who received ZA therapy due to bone metastases between March 2006 and December 2013. We recorded the patients' ages, weights, duration of treatment with ZA, number of ZA infusions, dental procedures, anticancer treatments (chemotherapy, aromatase inhibitor, trastuzumab), the presence of diabetes mellitus or renal dysfunction, and smoking habits.Thirteen patients (13.40%) had developed ONJ. Among the patients with ONJ, the mean time of exposure to ZA was 41 months (range: 13-82) and the mean number of ZA infusions was 38 (range: 15-56). The duration of treatment with ZA and the use of trastuzumab were observed to be 2 factors that influenced the development of ONJ (P = 0.049 and P = 0.028, respectively).The development of ONJ under ZA treatment may be associated solely with the duration of ZA treatment and the concurrent administration of trastuzumab. These findings show that patients who are administered trastuzumab for metastatic breast cancer while undergoing ZA treatment are prone to developing ONJ. Therefore, we recommend intense clinical observation to avoid this particular condition in patients receiving ZA and trastuzumab.

Zoledronate induces osteonecrosis of the jaw in sheep

INTRODUCTION

The treatment of bisphosphonate-related osteonecrosis of the jaw has become routine in maxillofacial hospitals. However, the etiopathology has not yet been fully understood. The aim of this study was to develop a large animal model for medication-related osteonecrosis of the jaw (MRONJ).

MATERIAL AND METHODS

Eight Swiss mountain sheep were randomly assigned into two groups. Group I received 0.075 mg/kg zoledronate (ZOL) intravenously every third week for 16 weeks. After 16 weeks, extraction of the first and second lower left premolar was performed. Group II underwent surgery and no ZOL was administered. After surgery, Group I continued to receive ZOL infusions; after 16 weeks, all animals were euthanized. The jaw bones were investigated macroscopically, radiographically (computed tomography) and histologically.

RESULTS

Osteonecrosis of the jaw was observed at all extraction sites in all the animals receiving ZOL, and at none of the sites in animals without ZOL. All ZOL-treated animals spontaneously developed exposed bone lesions in the oral cavity at sites where no surgical intervention was performed. CT imaging shows persistent alveolar extraction sockets 16 weeks after surgery in all animals of the ZOL-group, and healed alveolar extraction sockets in non-ZOL-treated animals.

CONCLUSION

Sheep treated with ZOL reproducibly demonstrated osteonecrosis of the jaw after tooth extraction, and spontaneous development of exposed bone in the oral cavity at sites where no manipulation was performed. This animal model can be used for further research in the fields of BP-ONJ etiopathology, oral implantology, bone and fracture healing and periodontology.

Effect of the cumulative dose of zoledronic acid on the pathogenesis of osteonecrosis of the jaws

Bisphosphonate-related osteonecrosis of the jaws (BRONJ) is a severe bone disease for which the pathogenetic mechanisms and risk factors are not fully understood. The present study evaluated the data of 652 patients with bone metastasis that had undergone treatment with biphosphonates. Subsequently, 24 patients with BRONJ and 20 control patients without BRONJ that were treated with zoledronic acid were enrolled. It was found that BRONJ occurred in 3.6% of patients. The mean age and the administration of dental treatment were found to be significantly associated with BRONJ development (P=0.049 and P=0.013, respectively). The cumulative dose median in the BRONJ group was found to be significantly higher compared with the cumulative dose average in the control group (P=0.037). In addition, at the time of BRONJ development, improvement in the disease was determined to be better in the BRONJ group than in the control group (P=0.031). The present study determined that age, the existence of dental extraction and the cumulative dose of zoledronate were all important risk factors in BRONJ development.

Incidence and risk predictors for osteonecrosis of the jaw in cancer patients treated with intravenous bisphosphonates

INTRODUCTION

The aim of this study was to establish the incidence of bisphosphonate-related osteonecrosis of the jaws (BRONJ) in oncologic patients and to determine risk predictors with respect to this condition.

MATERIAL AND METHODS

This retrospective review included 197 oncologic patients treated from January 2005 to December 2010 with administration of bisphosphonates (BPs) as part of management. Sex, age, type of cancer diagnosed, period of substantial disease, oral surgery, type of bisphosphonate, number of doses, and cases of BRONJ diagnosis were recorded. The cumulative incidence and incidence rate of BRONJ were calculated. The factors that influenced BRONJ were assessed with multivariate logistic regression and with estimations of 95% confidence intervals and odd ratios. Values of p ≤ 0.05 were considered significant.

RESULTS

The BRONJ appeared in 9.64% of patients. The BRONJ incidence rate was 1 in 28 patients per year of BP treatment. Logistic regression showed that the odds of osteonecrosis increased 1.0172-fold with each given dose of BP. The BRONJ risk with zoledronate was 5-fold higher than that with pamidronate or ibandronate. The risk of BRONJ increased by 40-fold after dental surgery.

CONCLUSIONS

Period of BP administration and type of BP used are important risk predictors for the development of BRONJ in oncologic patients treated with intravenous administration of these drugs. Patient-related factors are dental or periodontal events connected with need for oral surgery.

Drug induced osteonecrosis of the jaw

Despite the widespread use of bisphosphonates and their unequivocal efficacy for the treatment of various disease states, osteonecrosis of the jaw remains one of the most feared complications associated with their use. Current evidence, however, suggests that there is also a relationship between occurrence of osteonecrosis of the jaw and use of other classes of pharmacotherapies namely RANKL inhibitors as well as angiogenesis inhibitors. Although these drugs have different mechanisms of action than bisphosphonates, they all seem to interfere with the bone remodeling process i.e. alter the balance between bone resorption and bone formation which may be the most plausible explanation for pathogenesis of osteonecrosis of the jaw. The main objective of this review is to introduce the readership to a number of relatively new medications that may cause osteonecrosis of the jaw. Accordingly, we will summarize latest findings from clinical studies, meta analyses and case reports published in medical literature on this topic. For some of these medications, the evidence may not appear as robust as that for bisphosphonates; yet, the possibility of this adverse event occurring with these non bisphosphonate drugs should never be precluded unless proven otherwise. Thus, it is imperative that health care providers implement preventive measures so as to circumvent the incidence of osteonecrosis of the jaw. In this day of age where medical care is becoming personalized, we will highlight some of significant findings from studies seeking to identify genetic markers that may potentially play a role in development of osteonecrosis of the jaw.

Zoledronate induces bisphosphonate-related osteonecrosis of the jaw in osteopenic sheep

OBJECTIVES

Bisphosphonate-related osteonecrosis of the jaw (BP-ONJ) occurs in 1 % of patients with medication-induced osteoporosis treated with bisphosphonates. Sheep are an established large animal model for investigating osteoporotic skeletal changes. Zoledronate significantly reduces tissue mineral variability in ovariectomized sheep. The aim of this study was to analyze bone healing after tooth extraction in sheep with induced osteopenia and zoledronate administration.

MATERIALS AND METHODS

Eight adult ewes were randomly divided into two groups of four animals. All sheep underwent ovariectomy and a low-calcium diet. Dexamethasone was administered weekly for 16 weeks. Zoledronate was then given every third week for a further 16 weeks in four sheep; these infusions were repeated after extraction of two lower premolars. Four sheep without zoledronate administrations served as controls.

RESULTS

Due to general health conditions, two sheep of the zoledronate group had to be excluded before surgery. The remaining two sheep of this group developed BP-ONJ lesions at the extraction site and various other sites in both jaws. Control group animals showed uneventful wound healing. Histology of the alveolar processes as well as lumbar spine revealed larger portions of old bone and smaller portions of new bone in the zoledronate group.

CONCLUSIONS

This animal study showed uneventful wound healing after tooth extraction in osteopenic sheep whereas zoledronate treatment leads to development of BP-ONJ-like lesions.

CLINICAL RELEVANCE

As bisphosphonate administration is a standard treatment for glucocorticoid-induced osteoporosis, this model can be used for further research in pathogenesis and management of bisphosphonate-related adverse events.

Bisphosphonate-related osteonecrosis of jaw (BRONJ) in Japanese population: a case series of 13 patients at our clinic

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) affects quality of life and is an important problem for dentists. A Japanese position paper on BRONJ was published in 2010. The purpose of this study was to review clinical data on the treatment of BRONJ obtained at the Clinic of Oral and Maxillofacial Surgery, Tokyo Dental College, Chiba Hospital to further our understanding of this disease. A total of 13 patients (6 men and 7 women) were included. All the patients included in this study had received Bisphosphonate (BP) therapy and had BRONJ. Five of them (38.5%) had received oral BP therapy for osteoporosis, while the remaining 8 (61.5%) had received parenteral BP therapy for bone metastases from breast or prostate cancer. Osteoporosis patients were treated with risedronate or alendronate. Breast or prostate cancer patients were treated with zoledronate. Two patients with rheumatoid arthritis were treated with corticosteroid. Three patients had diabetes mellitus. Eleven patients were treated with antibiotics, while 5 underwent surgical treatment. Discontinuation of BP was recorded in 7 patients during dental treatment. Sequestration was observed in 6 patients during an 11-month follow-up. Eventually, healing and improvement of the oral mucosa were observed in 3 patients. The current standard treatment for BRONJ does not always provide good results. It is necessary to accumulate further clinical data to establish more effective treatment strategies for BRONJ.

Infection and Medication-related Osteonecrosis of the Jaw

Medication-related osteonecrosis of the jaw (MRONJ), although initially believed to be exclusively associated with bisphosphonates, has been implicated in recent reports with additional drugs, especially the bone antiresorptive denosumab. The pathophysiology has not been fully elucidated, and no causal association between bone antiresorptive regimens and MRONJ has yet been established. However, reduced bone turnover and infection, an almost universal finding, are thought to be central to the pathogenesis of MRONJ. Both bisphosphonates and denosumab, through different pathways of action, significantly reduce the rate of bone turnover and potentially reduce the efficacy of the host defense against infection. Recent evidence questions the simplified etiology of low bone turnover causing MRONJ and offers evidence on the prominent role of infection instead. The management of MRONJ remains a significant clinical challenge, with little progress having been made on treatment. The aim of this article is to explore the current theories on the etiology of MRONJ and to emphasize the importance of infection in the development of this devastating pathology.

Diagnosis and management of osteonecrosis of the jaw: a systematic review and international consensus

This work provides a systematic review of the literature from January 2003 to April 2014 pertaining to the incidence, pathophysiology, diagnosis, and treatment of osteonecrosis of the jaw (ONJ), and offers recommendations for its management based on multidisciplinary international consensus. ONJ is associated with oncology-dose parenteral antiresorptive therapy of bisphosphonates (BP) and denosumab (Dmab). The incidence of ONJ is greatest in the oncology patient population (1% to 15%), where high doses of these medications are used at frequent intervals. In the osteoporosis patient population, the incidence of ONJ is estimated at 0.001% to 0.01%, marginally higher than the incidence in the general population (<0.001%). New insights into the pathophysiology of ONJ include antiresorptive effects of BPs and Dmab, effects of BPs on gamma delta T-cells and on monocyte and macrophage function, as well as the role of local bacterial infection, inflammation, and necrosis. Advances in imaging include the use of cone beam computerized tomography assessing cortical and cancellous architecture with lower radiation exposure, magnetic resonance imaging, bone scanning, and positron emission tomography, although plain films often suffice. Other risk factors for ONJ include glucocorticoid use, maxillary or mandibular bone surgery, poor oral hygiene, chronic inflammation, diabetes mellitus, ill-fitting dentures, as well as other drugs, including antiangiogenic agents. Prevention strategies for ONJ include elimination or stabilization of oral disease prior to initiation of antiresorptive agents, as well as maintenance of good oral hygiene. In those patients at high risk for the development of ONJ, including cancer patients receiving high-dose BP or Dmab therapy, consideration should be given to withholding antiresorptive therapy following extensive oral surgery until the surgical site heals with mature mucosal coverage. Management of ONJ is based on the stage of the disease, size of the lesions, and the presence of contributing drug therapy and comorbidity. Conservative therapy includes topical antibiotic oral rinses and systemic antibiotic therapy. Localized surgical debridement is indicated in advanced nonresponsive disease and has been successful. Early data have suggested enhanced osseous wound healing with teriparatide in those without contraindications for its use. Experimental therapy includes bone marrow stem cell intralesional transplantation, low-level laser therapy, local platelet-derived growth factor application, hyperbaric oxygen, and tissue grafting.

Bone targeted therapies for the prevention of skeletal morbidity in men with prostate cancer

Men with prostate cancer suffer substantially from bone-related complications. Androgen deprivation therapy itself is a cause of loss of bone mineral density and is associated with an increased incidence of osteoporotic fractures. In advanced disease, bone is by far the most common site of metastasis. Complications of bone metastases prominently include pain and the potential for skeletal events such as spinal cord compression and pathologic fractures. Elevated osteoclast activity is an important aspect of the pathophysiology of both treatment-related osteoporosis and skeletal complications due to metastases. The osteoclast is therefore a therapeutic target. Denosumab is a fully human monoclonal antibody to receptor activator of nuclear factor-κ-B ligand that was designed to potently inhibit osteoclast activity and is the central focus of this review. Bisphosphonates, radiopharmaceuticals and systemically-active hormonal agents such as abiraterone acetate and enzalutamide have each been shown to improve skeletal morbidity in specific clinical situations. Denosumab is the only agent that has been shown to prevent osteoporotic fractures in men receiving androgen deprivation therapy and at elevated risk for fracture. It has also demonstrated superiority to the potent bisphosphonate zoledronic acid for the prevention of skeletal-related events in men with castration-resistant prostate cancer metastatic to bone. Efficacy and toxicity data will be discussed.

Medical treatment of breast cancer bone metastasis: from bisphosphonates to targeted drugs

Breast cancer bone metastasis causing severe morbidity is commonly encountered in daily clinical practice. It causes pain, pathologic fractures, spinal cord and other nerve compression syndromes and life threatening hypercalcemia. Breast cancer metastasizes to bone through complicated steps in which numerous molecules play roles. Metastatic cells disrupt normal bone turnover and create a vicious cycle to which treatment efforts should be directed. Bisphosphonates have been used safely for more than two decades. As a group they delay time to first skeletal related event and reduce pain, but do not prevent development of bone metastasis in patients with no bone metastasis, and also do not prolong survival. The receptor activator for nuclear factor κB ligand inhibitor denosumab delays time to first skeletal related event and reduces the skeletal morbidity rate. Radionuclides are another treatment option for bone pain. New targeted therapies and radionuclides are still under investigation. In this review we will focus on mechanisms of bone metastasis and its medical treatment in breast cancer patients.

Role of periodontal disease in bisphosphonate-related osteonecrosis of the jaws in ovariectomized rats

OBJECTIVE

This study aimed to investigate the role of progressive periodontal disease in inducing bisphosphonate-related osteonecrosis of the jaws (BRONJ) using an ovariectomized (OVX) rat model mimicking human intracortical remodeling process.

MATERIALS AND METHODS

Thirty 12-week-old Spraque-Dawly (SD) female rats were randomly assigned into two groups. All rats underwent bilateral ovariectomy. Six weeks after surgery, zoledronic acid (ZA) or vehicle control was administered intraperitoneally for 12 weeks. On the same day of injection, a cotton ligature was placed subgingivally around the first left lower molar to induce periodontitis. All animals were sacrificed 12 weeks after injection. The entire mandibles were harvested for micro-computed tomography (micro-CT) and histological examinations.

RESULTS

Micro-CT examination showed that ligature placement caused significant alveolar bone loss both in ZA (0.63 ± 0.13 vs. 0.38 ± 0.06 mm, P < 0.001) and in control (0.88 ± 0.19 vs. 0.40 ± 0.06 mm, P < 0.001) groups. Whereas in the ZA group, bone loss was attenuated compared with the control group (P < 0.01); the bone mineral density in the ZA group (1.00 ± 0.02 g/cm(3)) was significantly higher than that in vehicle control group (0.96 ± 0.03 g/cm(3), P < 0.001). Histological examination found necrotic bone tissue with extensive, empty lacunae in two of 15 rats in ZA group, but in none of the control group.

CONCLUSION

Bisphosphonates inhibit alveolar bone resorption in progressive periodontal disease, which might benefit the management of periodontitis, but increase the risk of developing BRONJ.

Characteristics of the early stages of intravenous bisphosphonate-related osteonecrosis of the jaw in patients with breast cancer

OBJECTIVE

The clinical features of the early stages of bisphosphonate-related osteonecrosis of the jaw (BRONJ) in patients with breast cancer remain unclear. A retrospective cohort study was conducted of patients with breast cancer who received intravenous bisphosphonate (BP) treatment in a single center in order to clarify the status of the early stages of BRONJ.

MATERIALS AND METHODS

A BRONJ oral monitoring program was established in 247 breast cancer patients given intravenous BP treatment at the institution. The differences in age, BP treatment period, number of remaining teeth, oral hygiene status, presence of regular oral monitoring and the existence of suspected BRONJ (stage 0) among eight BRONJ and 36 non-BRONJ subjects who completed oral examinations were then compared.

RESULTS

BRONJ was observed in 0.4% of subjects on the first visit to the oral surgery clinic and in 3.2% of subjects during the follow-up period. Logistic regression analysis revealed that the odds ratio for identifying patients with BRONJ during follow-up by the presence of stage 0 at first visit was 24.0 (95% confidence interval [CI] = 3.6-161.7). The area under the receiver operating characteristic curve for identifying subjects with BRONJ by the presence of stage 0 was 0.82 (95% CI = 0.63-1.00).

CONCLUSION

The results suggest that patients with stage 0 BRONJ on the first visit may progress to advanced BRONJ during the follow-up period. The oral monitoring program may contribute to the early detection of BRONJ.

Risk factors influencing the duration of treatment with bisphosphonates until occurrence of an osteonecrosis of the jaw in 963 cancer patients

OBJECTIVE

Osteonecrosis of the jaw (ONJ) is an adverse effect that is associated with bisphosphonate (BP) use. Little data are available on risk factors influencing the time of treatment until an osteonecrosis occurs.

METHODS

From 1 Dec 2004 until 21 Sep 2012, the German Register collected all patients with validated diagnoses of ONJ (N = 1,229) that were reported to the national pharmaco-vigilance system or to the Register directly. We analysed 963 patients with cancerous disease and an ONJ during i.v. BP treatment. Duration of BP treatment until first diagnosis of ONJ and Kaplan-Meier curves of ONJ-free survival were analysed stratified by gender, type of BP and type of cancer.

RESULTS

Main indications for BP treatment were breast cancer (36%), multiple myeloma (24%), prostate cancer (16%) and kidney cancer (4%). Men suffered from their ONJ earlier than women. A total of 780 patients (81%) had their ONJ during zoledronate treatment, 93 (10%) under pamidronate and 90 (9%) under ibandronate treatment. ONJ-free survival in single BP users was significantly longer in pamidronate-treated patients than in zoledronate or ibandronate users. Ibandronate users had the shortest median duration of treatment (17 months), similar to that of zoledronate users (21.5 months). Sequential prescription of two different BPs prolonged the period of overall BP treatment until an ONJ occurred. Time of BP treatment was shortest in patients with kidney cancer. Age or a concomitant osteoporosis did not influence the time to event of an ONJ.

CONCLUSION

Systemic risk factors such as gender play a significant role in certain subgroups only. Comparative analysis of different cancer patients helps the treating oncologist/dentist to identify patients with a more imminent risk to develop an ONJ (i.e. kidney cancer, ibandronate/zoledronate use).

Bisphosphonate-related osteonecrosis of the jaw: specificities

Bisphosphonate-related osteonecrosis of the jaws (BRONJ) is a severe complication that has recently emerged in patients treated with intravenous bisphosphonates for malignant diseases. This complication usually presents after a minor local trauma during a dental treatment. Several etiopathogenic mechanisms of this pathological condition have been proposed, but no model can explain all morphological changes observed at the macroscopic and microscopic level. BRONJ is likely to be related to direct toxicity in the bone and soft tissue cells, due to nitrogen-containing bisphosphonates. This review elucidates the clinical indications and mechanism of action of bisphosphonates, reports some clinical diagnostic criteria for BRONJ, describe the histopathological criteria for BRONJ diagnosis, the potential triggering pathways and the available treatment strategies.

Human isoprenoid synthase enzymes as therapeutic targets

In the human body, the complex biochemical network known as the mevalonate pathway is responsible for the biosynthesis of all isoprenoids, which consists of a vast array of metabolites that are vital for proper cellular functions. Two key isoprenoids, farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP) are responsible for the post-translational prenylation of small GTP-binding proteins, and serve as the biosynthetic precursors to numerous other biomolecules. The down-stream metabolite of FPP and GGPP is squalene, the precursor to steroids, bile acids, lipoproteins, and vitamin D. In the past, interest in prenyl synthase inhibitors focused mainly on the role of the FPP in lytic bone diseases. More recently pre-clinical and clinical studies have strongly implicated high levels of protein prenylation in a plethora of human diseases, including non-skeletal cancers, the progression of neurodegenerative diseases and cardiovascular diseases. In this review, we focus mainly on the potential therapeutic value of down-regulating the biosynthesis of FPP, GGPP, and squalene. We summarize the most recent drug discovery efforts and the structural data available that support the current on-going studies.

Bone health in breast cancer patients: a comprehensive statement by CECOG/SAKK Intergroup

Bone is the most common site of distant metastases in breast cancer that can cause severe and debilitating skeletal related events (SRE) including hypercalcemia of malignancy, pathologic fracture, spinal cord compression and the need for palliative radiation therapy or surgery to the bone. SRE are associated with substantial pain and morbidity leading to frequent hospitalization, impaired quality of life and poor prognosis. The past 25 years of research on the pathophysiology of bone metastases led to the development of highly effective treatment options to delay or prevent osseous metastases and SRE. Management of bone metastases has become an integral part of cancer treatment requiring expertise of multidisciplinary teams of medical and radiation oncologists, surgeons and radiologists in order to find an optimal treatment for each individual patient. A group of international breast cancer experts attended a Skeletal Care Academy Meeting in November 2012 in Istanbul and discussed current preventive measures and treatment options of SRE, which are summarized in this evidence-based consensus for qualified decision- making in clinical practice.

Targeted treatments of bone metastases in patients with lung cancer

Until now ~30–40% of patients with advanced lung cancer develop bone metastases, but as the newer therapies are extending survival, the chance of developing bone metastases increases. Bone metastases cause skeletal-related events (SREs) such as pathologic fractures, spinal cord compression, radiation therapy or surgery to bone, or hypercalcemia, which can have debilitating consequences affecting patients’ health-related quality of life (HR-QOL) and performance status (PS). Poor PS then prevents the patients to receive further lines of treatments, which are available today. SREs are associated with increased economic costs. In one clinical trial, the median time to first SRE was only 5 months. Early detection of bone metastases can prevent SREs and avoid inappropriate implementation of major surgery or chemoradiation therapy. With the new generation bisphosphonate zoledronic acid (ZA) or denosumab (anti-RANKL activity), one can reduce the number of patients who experience SREs, decrease the annual incidence of SREs and delay the median time to first SRE. These agents are effective even after the onset of SREs. They are well tolerated, with manageable side effects. The biochemical markers of bone metabolism especially N-telopeptide of type I collagen and bone specific alkaline phosphatase (BALP) can be both prognostic and predictive markers for the patients with bone metastases from non-small cell lung cancer (NSCLC). Anticancer activity of ZA and denosumab further supports their use as soon as bone metastases are diagnosed in patients with NSCLC. Further trials will inform us about the efficacy of these agents for prevention of bone metastases and even about possible effects on visceral metastases.

A large case-control study reveals a positive association between bisphosphonate use and delayed dental healing and osteonecrosis of the jaw

This study sought to investigate, using a case-control study design, the association between bisphosphonate therapy and delayed dental healing and osteonecrosis of the jaw. Identification of potential cases of delayed dental healing was by consecutive screening of Specialist Oral and Maxillofacial and Special Needs Dentist clinic records for patients aged older than 50 years, during a 6-month window, in Victoria, Australia. Cases were confirmed by a case adjudication panel blinded to bisphosphonate status. Cases associated with malignancy or local radiotherapy were excluded. Controls were matched for age, sex, and source of dental referral (1:4, n = 160 controls). Variables of interest were dental precipitants, dental clinic type, smoking history, and medical comorbidities. A total of 4212 of 22,358 patients met inclusion criteria, of which 69 were potential cases with 40 (0.95%) confirmed cases. The odds ratio (OR) for developing delayed dental healing when taking an oral bisphosphonate was 13.1 (95% confidence interval [CI] 4.4 to 39.3; p < 0.001). There were no cases associated with intravenous bisphosphonate use. There was some evidence of an interaction with age, sex, and clinic type. When adjusted for smoking, the estimated odds ratio was 11.6 (95% CI 1.9 to 69.4; p = 0.01). There was an association between having another illness and delayed dental healing (OR = 2.3; 95% CI 1.0 to 5.2). A dental precipitant was present in 39 of 40 (97.5%) delayed dental healing cases. An important association between bisphosphonate use and delayed dental healing in the setting of benign bone disease, predominately in individuals with a dental precipitant, has been demonstrated.

Incidence and risk of osteonecrosis of the jaw among the Taiwan osteoporosis population

Evidence of the incidence and risk of osteonecrosis of the jaw (ONJ) in Asian osteoporosis populations receiving different osteoporosis medications is lacking. We found that there is no excess incidence of or risk for ONJ in osteoporosis patients >50 years old using alendronate as compared with patients using raloxifene or calcitonin under real-world conditions in Taiwan.

INTRODUCTION

To provide information on ONJ in Asian populations, this study compares the incidence and risk of ONJ between patients receiving alendronate and those receiving non-bisphosphonate osteoporosis medications in Taiwan.

METHODS

Enrollees in the National Health Insurance Research Database (NHIRD) from 2003 to 2007, aged above 50 years, with vertebral/hip fracture, and new to osteoporosis therapy were recruited. Patients with Paget's disease or cancer during the baseline period were excluded. Patients were classified into either the alendronate or the calcitonin/raloxifene (control) group according to their exposure during follow-up. Previously proposed possible ONJ diagnosis codes were adopted as potential ONJ cases, but qualifying cases also had a repeated ONJ diagnosis within 8 weeks of the first diagnosis and received one or more broad-spectrum oral antibiotics. Cox modeling compared the risk of ONJ between the alendronate and the control groups, which were matched using propensity scores. Results were examined in series sensitivity analyses, including different cumulative dose groups.

RESULTS

We found 25 potential ONJ cases in the alendronate (N = 18,030) and 21 in the control groups (N = 25,615). Over the 6-year follow-up period, no increased risk of ONJ in the alendronate group in the original (hazard ratio (HR), 0.87; 95% confidence interval (CI), 0.47-1.58) or propensity score-matched cohorts (HR, 0.86; 95% CI, 0.44-1.69) was found. All comparison groups exhibited a similar incidence of ONJ, ranging from 6.9 to 8.2/10,000 person-years.

CONCLUSION

Under real-world conditions, there is no excess risk for ONJ in osteoporosis patients >50 years old using alendronate as compared with patients using raloxifene or calcitonin.

Early effects of parathyroid hormone on bisphosphonate/steroid-associated compromised osseous wound healing

SUMMARY

Administration of intermittent parathyroid hormone (PTH) promoted healing of tibial osseous defects and tooth extraction wounds and prevented the development of necrotic lesions in rats on a combined bisphosphonate and steroid regimen.

INTRODUCTION

Osteonecrosis of the jaw (ONJ) has emerged in association with antiresorptive therapies. The pathophysiology of ONJ is unknown and no established cure currently exists. Our objective was to determine the effect of intermittent PTH administration on early osseous healing in the jaw and long bones of rats receiving bisphosphonate and steroid treatment.

METHODS

Ovariectomized rats received the combination therapy of alendronate and dexamethasone (ALN/DEX) for 12 weeks. Osseous wounds were created in the jaw and tibia. PTH was administered intermittently and healing at 2 weeks post-op was compared between the jaw and tibia by microcomputed tomography and histomorphometric analyses.

RESULTS

ALN/DEX treatment was associated with necrotic open wounds in the jaw but had no negative effects on healing and promoted bone fill in tibial defects. PTH therapy prevented the development of necrotic lesions in the jaw and promoted healing of the tibial defects. PTH therapy was associated with the promotion of osteocyte survival in osseous wounds both in the jaw and tibia.

CONCLUSIONS

Wound healing was impaired in the jaw in rats on a combined bisphosphonate and steroid regimen, and PTH therapy rescued necrotic lesions. These findings suggest that PTH therapy could be utilized to prevent ONJ from occurring in patients on combination antiresorptive and steroid therapy.

Association of dental and periodontal status with bisphosphonate-related osteonecrosis of the jaws. A retrospective case controlled study

INTRODUCTION

To assess the association of oral hygiene, dental caries, and periodontal status with bisphosphonate-related osteonecrosis of the jaws.

MATERIAL AND METHODS

A retrospective case-control study on 81 patients treated for neoplasms with bone metastases. Twenty-nine patients with bone necrosis and 52 controls treated with bisphosphonates were compared using the Oral Hygiene Index, Decay, Missing, Filled Teeth, Community Periodontal Index of Treatment Needs, and Residual Periodontal Bone. The null hypothesis stated that there was no difference in parameters of oral health between patients with and without bone necrosis. Differences of means of above-mentioned variables were compared between the groups with Student's t-test or Mann-Whitney rank sum test and χ(2) test. Value of p ≤ 0.05 was considered significant.

RESULTS

Poorer oral hygiene (OHIs 1.94 vs. 1.32; p = 0.065), more advanced dental caries (DMFT 26.85 vs. 22.87; p = 0.05), and more advanced periodontal disease (CPITN: = 0: 21.05% vs. 42.51%; = 1 13.16% vs. 7.29%; = 2: 0% vs. 15.38%; = 3: 65.79% vs. 28.34%; = 4: 0% vs. 6.48%, Residual periodontal bone 73.1% vs. 80.51%; p = 0,001) were characteristic of patients with bisphosphonate related jaw necrosis when compared with control group. An advanced dental caries or periodontal disease required surgical intervention which directly contributed to the development of the bone necrosis.

CONCLUSIONS

Dental and periodontal disease can lead to bisphosphonate-related osteonecrosis of the jaw. Oncologic patients treated with bisphosphonates should be offered preventive care to reduce dental plaque, calculus, dental caries, and periodontal disease.

Epidemiology, clinical manifestations, risk reduction and treatment strategies of jaw osteonecrosis in cancer patients exposed to antiresorptive agents

ABSTRACT: Osteonecrosis of the jaws (ONJ) is an adverse side event of bisphosphonates and denosumab, antiresorptive agents that effectively reduce the incidence of skeletal-related events in patients with metastatic bone cancer and multiple myeloma. Available data suggest that 0–27.5% of individuals exposed to antiresorptive agents can develop ONJ. There is increasing evidence that avoidance of surgical trauma and infection to the jawbones can minimize the risk of ONJ, but there are still a significant number of individuals who develop ONJ in the absence of these risk factors. Bone necrosis is almost irreversible and there is no definitive cure for ONJ with the exclusion, in certain cases, of surgical resection. However, most ONJ individuals are affected by advanced incurable cancer and are often managed with minimally invasive nonsurgical interventions in order to control jawbone infections and painful symptoms. This article summarizes current knowledge of ONJ epidemiology, manifestations, risk-reduction and therapeutic strategies. Further research is needed in order to determine individual predisposition to ONJ and clarify the effectiveness of available treatments.

Plumbagin attenuates cancer cell growth and osteoclast formation in the bone microenvironment of mice

AIM

To investigate the effects of plumbagin, a naphthoquinone derived from the medicinal plant Plumbago zeylanica, on human breast cancer cell growth and the cancer cell-induced osteolysis in the bone microenvironment of mice.

METHODS

Human breast cancer cell subline MDA-MB-231SA with the ability to spread and grow in the bone was tested. The cell proliferation was determined using the CCK-8 assay. Apoptosis was detected with Annexin V/PI double-labeled flow cytometry. Red fluorescent protein-labeled MDA-MB-231SArfp cells were injected into the right tibia of female BALB/c-nu/nu mice. Three days after the inoculation, the mice were injected with plumbagin (2, 4, or 6 mg/kg, ip) 5 times per week for 7 weeks. The growth of the tumor cells was monitored using an in vivo imaging system. After the mice were sacrificed, the hind limbs were removed for radiographic and histological analyses.

RESULTS

Plumbagin (2.5-20 μmol/L) concentration-dependently inhibited the cell viability and induced apoptosis of MDA-MB-231SA cells in vitro (the IC50 value of inhibition of cell viability was 14.7 μmol/L). Administration of plumbagin to breast cancer bearing mice delayed the tumor growth by 2-3 weeks and reduced the tumor volume by 44%-74%. The in vivo imaging study showed that plumbagin dose-dependently inhibited MDA-MB-231SArfp cell growth in bone microenvironment. Furthermore, X-ray images and micro-CT study demonstrated that plumbagin reduced bone erosion area and prevented a decrease in bone tissue volume. Histological studies showed that plumbagin dose-dependently inhibited the breast cancer cell growth, enhanced the cell apoptosis and reduced the number of TRAcP-positive osteoclasts.

CONCLUSION

Plumbagin inhibits the cell growth and induces apoptosis in human breast cancer cells in mice bone microenvironment, leading to significant reduction in osteolytic lesions caused by the tumor cells.

Suppressive Effects of Plumbagin on Invasion and Migration of Breast Cancer Cells via the Inhibition of STAT3 Signaling and Down-regulation of Inflammatory Cytokine Expressions

OBJECTIVE

The aim of this study was to investigate the effects of plumbagin (PL), a naphthoquinone derived from the medicinal plant plumbago zeylanica, on the invasion and migration of human breast cancer cells.

METHODS

Human breast cancer MDA-MB-231SArfp cells were treated with different concentrations of plumbagin for 24 h. The effects of plumbagin on the migration and invasion were observed by a transwell method. The expressions of IL-1α, IL-1β, IL-6, IL-8, TGF-β, TNFα, MMP-2 and MMP-9 mRNA in MDA-MB-231SArfp cells were detected using Real-Time PCR. MDA-MB-231SArfp cells were treated with plumbagin at different concentrations for 45 minutes. The activation of STAT3 was detected by western blot. Following this analysis, STAT3 in MDA-MB-231SArfp cells was knocked out using specific siRNA. mRNA levels of IL-1α, TGF-β, MMP-2 and MMP-9 were then detected. Consequently, MDA-MB-231SArfp cells were injected intracardially into BALB/c nude mice to construct a breast cancer bone metastatic model. The mice were injected intraperitoneally with plumbagin. Non-invasive in vivo monitoring, X-ray imaging and histological staining were performed to investigate the effects of plumbagin on the invasion and migration of breast cancer cells in vivo.

RESULTS

The in vitro results showed that plumbagin could suppress the migration and invasion of breast cancer cells and down-regulate mRNA expressions of IL-1α, TGF-β, MMP-2 and MMP-9. Western blotting demonstrated that plumbagin inhibited the activation of STAT3 signaling in MDA-MB-231SArfp cells. The inactivation of STAT3 was found to have an inhibitory effect on the expressions of IL-1α, TGF-β, MMP-2 and MMP-9. In vivo studies showed that plumbagin inhibited the metastasis of breast cancer cells and decreased osteolytic bone metastases, as well as the secretion of MMP-2 and MMP-9 by tumor cells at metastatic lesions.

CONCLUSIONS

Plumbagin can suppress the invasion and migration of breast cancer cells via the inhibition of STAT3 signaling and by downregulation of IL-1α, TGF-β, MMP-2 and MMP-9.