Risk of osteonecrosis of the jaw in cancer patients taking bisphosphonates

Therapeutic approach and management algorithms in medication-related osteonecrosis of the jaw (MONJ): recommendations of a multidisciplinary group of experts

BACKGROUND

The justification for this consensus is the absence of local protocols on Medication-Related Osteonecrosis of the Jaws (MONJ), for prevention, evaluation, and treatment, involving physicians and dentists, leading to suspension of antiresorptive treatments, despite their benefit in the prevention of fragility fractures (40-70%). These fractures cause disability and mortality (80% and 20-30%, respectively), as opposed to the low risk associated with MONJ in osteoporotic (0.01-0.03%) and oncological patients (1.3-1.8%).

PURPOSE

To provide management recommendations through algorithms that guide health professionals to prevent, diagnose, and treat MONJ in different clinical scenarios.

METHOD

A technical multidisciplinary team composed of specialists with extensive experience in osteoporosis or osteonecrosis of the jaw from Fundación Santa Fé (Bogotá, Colombia) and the Asociación Colombiana de Osteoporosis y Metabolismo Mineral was selected. Three rounds were carried out: definition of questions, answers using Delphi methodology, and the discussion of questions in order to have an agreement. The whole group participated in two phases, and the developer group in the total number of rounds. A literature review was conducted to obtain academic support to design questions with clinical relevance.

RESULTS AND CONCLUSIONS

The consensus group generated definitions and recommendations useful for doctors and dentists, following clinical algorithms involving four scenarios: osteoporosis patient who requires dental procedures and has not received antiresorptives, osteoporosis patient who are under treatment with antiresorptives, cancer patients, and MONJ-instituted patients. The therapeutic approach in osteoporosis and cancer patients, in invasive dental procedures, must be relied on the risk-benefit treatment.

Current Controversies on the Pathogenesis of Medication-Related Osteonecrosis of the Jaw

Medication-related osteonecrosis of the jaw (MRONJ) was first reported more than a decade ago. Since then, numerous cases have been diagnosed. Currently, there are three groups of drugs related to MRONJ: bisphosphonates, denosumab and anti-angiogenic drugs. As MRONJ can lead to debilitating clinical sequels and limited effective treatment options are available, much research has been done in understanding its pathophysiology. Until now, the exact pathogenesis of MRONJ has not been fully elucidated. While history of invasive dental procedures or local trauma may be present, some cases occur spontaneously without any preceding factors. This review aims to examine and discuss the three main hypotheses for the pathogenesis of MRONJ, namely suppressed bone turnover, cellular toxicity and infection.

[Bisphosphonate-associated osteonecrosis of the jaw]

BACKGROUND

Bisphosphonates (BP) are used in the treatment of severe osteoporosis and metastasis of malignant diseases. A possible relationship between the occurrence of osteonecrosis of the jaw and BP therapy was first described in 2003. Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is difficult to treat. In some cases the condition of the patients is so compromised that only minimally invasive surgery is possible. Histopathologically, osteonecrosis shows the features of chronic sequestered osteomyelitis, which can be found in different areas of the upper and lower jaw. Sometimes extensive resections of the jaw are necessary. Thus, BRONJ can cause mutilation, impairment of function and esthetics in the orofacial system and, thereby, compromise the life quality of the patients. Triggering factors are often tooth extraction without surgical plastic wound closure of the alveoli, but can also be associated with bruises from denture or other minor wounds.

OBJECTIVES

The purpose of this article is to present results from our own patient collective, including therapy regime, success rate, and therapy recommendations.

METHODS

The patient populations at three German hospitals were analyzed using a standard questionnaire. The patients in the study group, entered into a follow-up system for early detection of possible BRONJ, were evaluated for treatement outcome.

RESULTS

The success rate for prophylactic surgery in asymptomatic patients was very high at 96 %. In the group with symptomatic BRONJ, the outcome was significantly lower (76.4 %).

CONCLUSIONS

Because of the complex symptoms, close cooperation between oncologists, dentists, and maxillofacial surgeons is required in the treatment of BRONJ. Before starting therapy with bisphosphonates and during the therapy, dental treatment and monitoring of the patient' oral health is necessary.

Bone-Targeted Agents for the Management of Breast Cancer Patients with Bone Metastases

Despite advances in adjuvant therapy for breast cancer, bone remains the most common site of recurrence. The goal of therapy for these patients is palliative and focused on maximizing the duration and quality of their life, while concurrently minimizing any disease or treatment-related complications. Bone metastases predispose patients to reduced survival, pain, impaired quality of life and the development of skeletal-related events. With an increased understanding of the pathophysiology of bone metastasis, effective treatments for their management have evolved and are now in widespread clinical use. This article will discuss the pathogenesis of bone metastases and review the key clinical evidence for the efficacy and safety of currently available systemic bone-targeted therapies in breast cancer patients with an emphasis on bisphosphonates and the receptor activator of nuclear factor kappa B ligand (RANKL) inhibitors. We will also discuss novel strategies and therapies currently in development.

Bisphophonates related osteonecrosis of the jaw

OBJECTIVE

With sporadic reporting of BPs related osteonecrosis of jaw and in absence of definitive guidelines regarding the management of such patients, the dentists and the oral and maxillofacial surgeons need to be updated about this issue. The objective of this article was to produce an updated bibliographic review of BPs related ONJ. This paper reviews the literature regarding the same for better understanding of the problem and its management.

BACKGROUND

Bisphosphonates (BPs) are potent inhibitors of bone resorption and are widely used in the treatment of osteoporosis and other diseases that cause bone mass loss, such as Paget's disease, bone metastases, and multiple myeloma, to prevent pathological fractures. With increasing use, evidence is emerging that patients taking BP drugs are at risk of developing osteonecrosis of the jaws (ONJs), sometimes occurring spontaneously, but more commonly following dental extractions or oral bone surgery.

MATERIALS AND METHODS

A bibliographic search was carried out using PubMed, Medline, and search engines ending in April, 2013. The search terms used were: Oral BPs, dental implants, and osteonecrosis.

CONCLUSION

On the basis of available literature, the management of patients on bisphosphonates requiring dental treatment is classified according to the duration of BPs treatment, method of administration of BPs etc. Dental treatments when planned carefully in such patients have a fair to good prognosis.

Reducing the burden of bone metastases: current concepts and treatment options

BACKGROUND

Bone metastases occur frequently in patients with solid tumours such as those of the prostate, breast and lung, and are associated with an increased risk of skeletal-related events (SREs). This article reviews the personal, social and economic burdens of bone metastases and SREs, and approaches to treatment.

METHODS

PubMed searches were conducted using a broad range of search terms. Articles identified were refined by author review of abstracts. Additional material was identified by searching recent relevant congress abstracts.

RESULTS

Bone metastases often decrease quality of life, but quantitative data on the extent of this effect are limited. Data from the USA demonstrate a significant financial burden associated with bone metastases; similar trends are now being uncovered in Europe as the number of assessments of health economics and healthcare resource utilisation in the region increases. The bisphosphonate zoledronic acid reduces the incidence of SREs compared with placebo. Recent phase 3 studies have shown that therapy with the RANK ligand inhibitor denosumab is superior to zoledronic acid for preventing or delaying SREs in patients with bone metastases from solid tumours. Denosumab also has a comparable safety profile to bisphosphonates, with reduced risk of renal toxicity and acute phase reactions. Data from Europe suggest that denosumab is cost-effective for the prevention of SREs compared with zoledronic acid. Additionally, several new experimental bone-targeted agents show promise.

CONCLUSION

Recent progress may help to reshape evidence-based guidelines to improve patient care and reduce the economic burden of bone metastases.

Oral care and the use of bone-targeted agents in patients with metastatic cancers: A practical guide for dental surgeons and oncologists

BACKGROUND

Bone-targeted agents such as bisphosphonates and the RANKL antibody have revolutionised the care of patients with bone metastases. There has, however been increasing concern about the oral health of these patients and in particular osteonecrosis of the jaw (ONJ), especially with the increasing use of these agents at higher potencies for greater periods of time.

METHODS

A review of the published data in PubMed and meeting abstracts was performed to examine incidence, risk factors, pathogenesis, clinical course and management of osteonecrosis of the jaw with focus on cancer patients treated with bone-targeted agents (BTA) for bone metastases. This manuscript takes the most frequent and pertinent questions raised by oncologists, dentists and oral and maxillofacial surgeons and tries to give a pragmatic overview of the literature.

RESULTS

The incidence of ONJ varies depending on types of bone-targeted agents, duration of treatment and additional risk factors. The causes and pathogenesis of ONJ is not fully elucidated, however bone-targeted therapy induced impaired bone remodelling, microtrauma secondary to jaw activity, and oral bacterial infection seem to be important factors. Since the treatment options for ONJ are limited and not well established, preventive strategies have to be included in patients management.

CONCLUSIONS

Many unanswered questions remain about the optimal oral care of patients receiving bone-targeted agents. Prospective data collection will remedy this and help to provide practical guidelines for the management and treatment of those patients that require dental intervention.

Bone-targeted agents and skeletal-related events in breast cancer patients with bone metastases: the state of the art

Most women with advanced breast cancer will develop bone metastases, which are associated with the development of skeletal-related events (sres) such as pathologic fractures and spinal cord compression. This article reviews the evolving definition and incidence of sres, the pathophysiology of bone metastases, and the key evidence for the safety and efficacy of the currently available systemic treatment options for preventing and delaying sres in the setting of breast cancer with bone metastases.The bisphosphonates are structural analogues of endogenous pyrophosphate; three of them (clodronate, pamidronate, and zoledronate) are currently approved for use in Canada in the setting of breast cancer with bone metastases. Denosumab is a fully human immunoglobulin G2 monoclonal antibody that binds to human rankl (receptor activator of nuclear factor κB ligand), thereby preventing osteoclast formation, function, and survival, and reducing cancer-induced destruction of bone. Denosumab has recently been approved in Canada for reducing the risk of sres from the bone metastases associated with a variety of malignancies, including breast cancer. How to predict the patients that will benefit most from prophylactic treatment, the agents to select and the timing of switches between agents, the dosing schedules and durations of treatment to choose, the potential utility of the agents in the adjuvant setting, and the utility of additional endpoints such as markers of bone resorption are among the outstanding questions with respect to the optimal use of antiresorptive agents for patients with breast cancer and bone metastases.

Bone matters in lung cancer

BACKGROUND

Bone metastases are a significant and undertreated clinical problem in patients with advanced lung cancer.

DESIGN

We reviewed the incidence of bone metastases and skeletal-related events (SREs) in patients with lung cancer and examined the burden on patients' lives and on health care systems. Available therapies to improve survival and lessen the impact of SREs on quality of life (QoL) were also investigated.

RESULTS

Bone metastases are common in lung cancer; however, owing to short survival times, data on the incidences of SREs are limited. As with other cancers, the costs associated with treating SREs in lung cancer are substantial. Bisphosphonates reduce the frequency of SREs and improve measures of pain and QoL in patients with lung cancer; however, nephrotoxicity is a common complication of therapy. Denosumab, a recently approved bone-targeted therapy, is superior to zoledronic acid in increasing the time to first on-study SRE in patients with solid tumours, including lung cancer. Additional roles of bone-targeted therapies beyond the prevention of SREs are under investigation.

CONCLUSIONS

With increasing awareness of the consequences of SREs, bone-targeted therapies may play a greater role in the management of patients with lung cancer, with the aim of delaying disease progression and preserving QoL.

Antibiotic effects on bacterial profile in osteonecrosis of the jaw

OBJECTIVE

Oral infection is considered to play a critical role in the pathogenesis of bisphosphonate-related osteonecrosis of the jaw (BRONJ), and antibiotic therapy has become a mainstay of BRONJ therapy. This study was aimed to investigate the effect of antibiotics on bacterial diversity in BRONJ tissues.

MATERIALS AND METHODS

The bacterial profile from soft tissues associated with the BRONJ lesion was determined using 16S rRNA-based denaturing gradient gel electrophoresis (DGGE) and sequencing. Twenty BRONJ subjects classified as stage 0-2 were enrolled in this study, and patient groups were divided into an antibiotic cohort (n=10) treated with systemic antibiotic and a non-antibiotic cohort (n=10) with no prior antibiotic therapy.

RESULTS

The DGGE fingerprints indicated no significant differences in bacterial diversity of BRONJ tissue samples. Patients on antibiotics had higher relative abundance of phylum Firmicutes with bacterial species, Streptococcus intermedius, Lactobacillus gasseri, Mogibacterium timidum, and Solobacterium moorei, whereas patients without antibiotics had greater amounts of Parvimonas micra and Streptococcus anginosus. Thirty percent of bacterial populations were uncultured (yet-to be cultured) phylotypes.

CONCLUSION

This study using limited sample size indicated that oral antibiotic therapy may have a limited efficacy on the bacterial population associated with BRONJ lesions.

Bisphosphonate-related osteonecrosis of the maxilla and sinusitis maxillaris

Bisphosphonates (BPs) are widely used as bone-stabilizers, but side effects of BP therapy include bisphosphonate-related osteonecrosis of the jaw (BRONJ), which is resistant to therapy. The aim of this study was to evaluate the outcome of maxillary BRONJ involving sinusitis maxillaris. 21 patients presenting with maxillary BRONJ, from 2005 to 2008, were included in the study. In 18 cases BP had been administered for carcinoma and in 3 cases for osteoporosis, with an average exposure time of 47.4 months. 12 patients spontaneously developed BRONJ. The 10 patients diagnosed with stage III BRONJ presented with concomitant sinusitis maxillaris. Despite treatment, there were six recurrences of BRONJ, four of them with additional sinusitis maxillaris. Whether BRONJ occurred spontaneously or after extraction there was no difference in the outcome. Patients with advanced maxillary BRONJ often suffer from sinusitis maxillaris, both of which are frequently resistant to therapy.

Jaw osteonecrosis in patients treated with bisphosphonates: an ultrastructural study

Osteonecrosis of the jaw is a severe bone disorder traditionally associated with periodontal disease, local malignancy, chemotherapy, glucocorticoid therapy, or trauma. Recently a growing number of publications reported the occurrence of osteonecrosis of the jaw in patients undergoing treatment with bisphosphonates. The mechanism by which bisphosphonates might contribute to the development of osteonecrosis of the jaw is far from being fully elucidated. Suppression of bone turnover, infection, tissue hypoxia and cellular toxicity were proposed as possible mechanisms by which bisphosphonates may exert adverse effects on bone metabolism. Here, we studied 25 consecutive patients treated with bisphosphonates for osteoporosis or tumoral pathologies. We provide good evidence of hyperactive osteoclastic bone resorption and suggest a direct cytotoxic effect of bisphosphonates on bone tissue through induction of osteocyte cell death. We also demonstrate that bisphosphonates only have limited adverse effects on bone vascular network.