American Society of Clinical Oncology 2003 update on the role of bisphosphonates and bone health issues in women with breast cancer

Bisphosphonates and jaw osteonecrosis in patients with advanced breast cancer

BACKGROUND

In recent years, several cases of mandibular necrosis associated with long-term use of bisphosphonates have been reported. The estimated incidence varies from 1% to 4.6%.

PATIENTS AND METHODS

We conducted an observational study with the aim of determining the incidence of jaw osteonecrosis in advanced breast cancer patients with bone metastases under bisphosphonate treatment and to identify subjects at higher risk of developing this complication evaluating preclinical signs. We considered two groups of patients. All the patients complaining of odontostomatological symptoms underwent maxillary CT scan and maxillo-surgeon clinical examination. Asymptomatic patients were asked to perform a standard orthopantomography (OPT).

RESULTS

From February 2005 to October 2005, we observed five patients with jaw bone necrosis (6%). Diagnosis was radiological and clinical. In two patients a confirmatory biopsy was performed. In the same time interval, OPTs were collected from 76 asymptomatic patients. Three OPTs revealed radiological features of suspicious mandibular necrosis. Maxillary CT scan confirmed the presence of an osteolityc area with signs of periosteal reaction. All the three patients were referred to maxillo-surgeon and two out of three patients underwent mandibular biopsy, but histopathological results were not conclusive.

CONCLUSIONS

In our experience, the incidence of jaw bone necrosis in breast cancer patients seems to be higher than in other reports (6%). Radiological features of suspicious jaw necrosis were observed in three asymptomatic patients. We do not know how these findings should be considered. Anyway, standard OPT is a simple procedure, and may allow identification of periodontal conditions that in some way can predispose to the development of this uncommon event.

Phase II trial evaluating the palliative benefit of second-line zoledronic acid in breast cancer patients with either a skeletal-related event or progressive bone metastases despite first-line bisphosphonate therapy

PURPOSE

This study evaluated whether additional palliative benefits could be derived from the second-line use of the more potent bisphosphonate zoledronic acid in metastatic breast cancer patients with either progressive bone metastases or skeletal-related events (SRE), despite first-line therapy with either pamidronate or clodronate.

PATIENTS AND METHODS

This prospective study evaluated the impact of second-line zoledronic acid on pain, quality of life, and markers of bone turnover (for example, urinary N-telopeptide [NTX]). Patients received monthly zoledronic acid (4 mg) for 3 months. Study evaluations were made weekly during the first month and again at week 8. No changes in chemotherapy or endocrine therapy were allowed in the month before or after commencing study treatment.

RESULTS

Thirty-one women completed this study. By week 8, patients had experienced significant improvements in pain control (P < .001). There was a downward trend in urinary NTX levels over the same time period (P = .008). Overall, there was a trend towards a positive correlation between improvement in pain control and reduction in week one urinary NTX relative to baseline (Spearman's rho r = 0.27; P = .15).

CONCLUSION

This is the first study to demonstrate that patients with either progressive bone metastases or SREs while on clodronate or pamidronate can have relevant palliative benefits with a switch to the more potent bisphosphonate zoledronic acid. This is reflected by significant improvements in pain control and bone turnover markers. If confirmed in randomized trials, these findings have major implications to the use of bisphosphonates in both the metastatic and adjuvant settings.

Incident pain and analgesic consumption decrease after samarium infusion: a pilot study

OBJECTIVE

The aim of this pilot study was to observe the variations of pain intensity on movement and at rest and the variation of analgesic drug consumption in patients with prostate cancer and painful bone metastases treated with a single dose of 1.0 mCi/kg of samarium-153 (153-Sm) lexidronam.

DESIGN

Case series.

SETTING

The Nuclear Medicine Unit and Pain Therapy and Palliative Care Unit, National Cancer Institute of Milan, Italy.

PATIENTS

Thirteen outpatients with hormone refractory prostate cancer and painful multiple bone metastases.

INTERVENTIONS

Infusion of a single dose of 1.0 mCi/kg of 153-Sm lexidronam, pain therapy, and the assessment of pain intensity at rest and on movement.

MAIN OUTCOME MEASURES

Variation of pain intensity on movement and at rest by means of a verbal scale and the reduction of analgesic drug consumption 4 weeks after infusion of 153-Sm lexidronam.

RESULTS

From baseline, 61.5% of patients reported a decrease of at least two levels of pain intensity on movement and 53.8% of patients had an improvement of pain at rest. Of the patients, 15.4% were not in pain at rest or on movement at baseline and continued to be free of pain 4 weeks after the administration of samarium. All ten patients, but one, who were on analgesic drugs before samarium infusion, reduced the regular drug administration or rescue medication. Bone marrow toxicity was mild and readily reversible in three patients.

CONCLUSIONS

In patients with bone metastases, pain on movement is a frequent and often difficult clinical problem to treat and the most frequent cause of breakthrough pain. In patients with painful multiple bone metastases due to prostate cancer, the infusion of a single dose of 1.0 mCi/kg of 153-Sm lexidronam may be considered an effective and safe treatment for pain either at rest or during movement.

Risk of cancer treatment-associated bone loss and fractures among women with breast cancer receiving aromatase inhibitors

BACKGROUND

Aromatase inhibitors (AIs) are a novel hormonal therapy for patients with breast cancer. However, AIs can cause bone loss by blocking estrogen production. This study aims to assess the association between AIs and treatment-related bone loss in a large managed-care population of women with breast cancer.

PATIENTS AND METHODS

With use of medical and pharmacy claims, data from > 5 million beneficiaries between January 1, 1998, and January 31, 2005, we identified 12,368 patients with > or = 2 breast cancer claims in a 6-month period who also had no bone metastases and no previous osteoporosis or fracture claims. Patients who had received antiestrogen (eg, tamoxifen) therapy were also excluded. One thousand three hundred fifty-four patients receiving an AI (anastrozole, exemestane, or letrozole) were compared with 11,014 controls who did not receive an AI with respect to their risk of bone loss. The observation start date for the AI and control groups was defined as the service date of the first AI claim and breast cancer claim, respectively. The endpoints include (1) bone loss, consisting of osteoporosis or osteopenia, and (2) clinical fractures.

RESULTS

The univariate analysis found that the prevalence of bone loss was 8.7% in the AI group versus 7.1% in the control group, resulting in a significant relative risk of 1.3 (95% confidence interval [CI], 1.1-1.6; P = 0.01). The prevalence of bone fracture was also significantly increased in the AI group compared with the controls (13.5% vs. 10.3%) with a relative risk of 1.4 (95% CI, 1.2-1.6, P = 0.001). Multivariate Cox proportional hazards regressions showed that after adjusting for age and comorbidities, the risk of bone loss remained significantly higher in the AI group than in the non-AI group, with a 27% (95% CI, 4%-55%; P = 0.02) and 21% (95% CI, 3%-43%; P = 0.02) increase in the risk of bone loss and fractures, respectively.

CONCLUSION

This retrospective longitudinal analysis of a large cohort of patients with breast cancer corroborates previous findings from smaller clinical trials and demonstrates that AI therapies carry an increased risk of bone loss. Monitoring and treatment management strategies to reduce bone loss risk are warranted in women receiving an AI for breast cancer.

Jaw avascular osteonecrosis after treatment of multiple myeloma with zoledronate

PURPOSE

Multiple myeloma, the second most common haematopoietic cancer, which represents the collection of plasma-cell neoplasms that invariably becomes fatal when self-renewing myeloma cells begin unrestrained proliferation. The major clinical manifestation of multiple myeloma is related to the loss of bone through osteolysis. This can lead to pathologic fractures, spinal cord compression, hypercalcaemia, and pain. It is also a major cause of morbidity and mortality in these patients, who frequently require radiation therapy, surgery and analgesic medications. Bisphosphonates are specific inhibitors of osteoclastic activity, and are currently used to prevent bone complications and to treat malignant hypercalcaemia in patients with multiple myeloma, or bone metastases from breast and prostate cancers. Hence, osteonecrosis of the mandible has been reported in three patients from Centro Hospitalar de Vila Nova de Gaia (CHVNG) with multiple myeloma treated for over 18-48 months with intravenous zoledronate, commonly prescribed for multiple myeloma therapy. Although, this report alerts clinicians about the potential complication of bone necrosis in patients receiving bisphosphonate therapy, many questions remain concerning the underlying pathogenesis of this process.

PATIENTS AND METHODS

The medical and dental records of three patients with multiple myeloma, who were treated in CHVNG in the past 4 years, were reviewed. These three patients presented exposed bone and osteonecrosis of the mandible, and shared one common clinical feature: all of them were treated with bisphosphonate zoledronate, administered intravenously for long periods. Sequential orthopantomograms (OPGs) and histological evaluation have been analysed from the biopsies of the non healing dental extraction sites of these patients.

RESULTS

After a routine dental extraction, these patients developed avascular osteonecrosis of the mandible and secondary bone infection with Actinomyces israelii (actinomycotic osteomyelitis), with no evidence of metastatic disease evaluated by biopsy. In these three described clinical cases, surgical debridment without flap elevation, intensive antibiotherapy and the suspension of the zoledronate treatment allowed a partial recovery of the patients. The purpose of this clinical report is to point out that patients suffering from multiple myeloma can develop bone osteonecrosis induced by treatment with bisphosphonates. Research to determine the mechanism of this dental phenomenon is needed to fully validate and substantiate the possible link between bisphosphonate treatment of multiple myeloma or other cancer diseases and avascular osteonecrosis of the jaws. Until then, clinicians involved in the care of patients at risk should consider this possible complication.

The role of bisphosphonates in the treatment of prostate cancer: recommendations from an expert panel

In this study, we provide consensus guidelines for the use of bisphosphonates in men with prostate cancer. To this end, an expert panel composed of urologists, medical oncologists, radiation oncologists, and endocrinologists met to review current clinical evidence for the use of bisphosphonates in patients with different stages of prostate cancer to derive consensus recommendations. Physicians should be proactive in monitoring bone loss in patients receiving long-term androgen-deprivation therapy for prostate cancer. Further study is needed before recommending the routine use of bisphosphonates in men with nonmetastatic prostate cancer. However, if a patient has clinically significant bone loss, use of a bisphosphonate to prevent further compromise of bone integrity should be strongly considered, regardless of hormonal and metastatic status. Bone scans are the preferred method for the identification of bone metastases. In patients with hormone-refractory prostate cancer and bone metastases, zoledronic acid is the only bisphosphonate indicated for the prevention of skeletal complications. In conclusion, patients with prostate cancer are at high risk for skeletal morbidity. Bisphosphonates have been shown to prevent cancer treatment-induced bone loss in men receiving androgen-deprivation therapy as well as skeletal complications in men with bone metastases. However, further study of the use of bisphosphonates across the clinical spectrum of prostate cancer is needed.

Sequence- and concentration-dependent effects of acute and long-term exposure to the bisphosphonate ibandronate in combination with single and multiple fractions of ionising radiation doses in human breast cancer cell lines

Both bisphosphonates and radiotherapy are highly effective for the management of bone metastases. Our in vitro study examined the cytotoxic effects resulting from combinations of ibandronate and ionising radiations (RX) in various sequences on breast cancer cells. Single radiation doses were given before, at halftime of, or after acute ibandronate incubation (48 h). Single or fractionated radiation doses were applied at the end of chronic ibandronate incubation (5 weeks). Combination of acute ibandronate exposure and single radiation doses led to synergistic cytotoxic effects in MDA-MB-231 cell line, but only with low ibandronate concentrations in MCF-7 cell line. In both cell lines, synergy was more marked when ibandronate followed RX. After long-term ibandronate exposure, only high single radiation doses induced synergistic effects in MDA-MB-231 cell line. Synergy was only detected with low ibandronate concentrations in MCF-7 cell line. In both cell lines, fractionated radiation doses exerted similar effects. The combination of ibandronate with radiation can exert synergistic effects on the inhibition of breast cancer cells growth, depending on cell line, drug sequence and dosage. Our data might provide a rationale for associating bisphosphonates and radiotherapy for the treatment of bone metastases from breast cancer.

Incidence and management of side effects associated with aromatase inhibitors in the adjuvant treatment of breast cancer in postmenopausal women

OBJECTIVE

Third-generation aromatase inhibitors (AIs) are effective and generally well-tolerated as adjuvant therapy. These AIs are now being introduced for the adjuvant treatment of postmenopausal patients with estrogen-receptor-positive early-stage breast cancer. However, questions remain about their long-term safety. This paper summarizes the adverse events reported in third-generation AI trials and comments on the appropriate management of these drug-induced adverse events in patients.

METHODS

Papers relating to anastrozole, exemestane, and letrozole were identified through Medline searches, and proceedings of recent oncology meetings were also reviewed to capture relevant emerging data.

RESULTS

The most commonly reported adverse events associated with adjuvant AI therapy include hot flushes and musculoskeletal complaints/arthralgia. The incidence of endometrial cancer and thromboembolic events is significantly lower with an AI than with tamoxifen. However, there is a small but significant increase in the risk of osteoporosis and fractures with AI therapy. A potential negative effect on the cardiovascular system, specifically on lipid metabolism, has not been conclusively demonstrated. No significant differences in overall quality of life were observed in studies comparing AIs with tamoxifen or placebo.

CONCLUSION

AIs alone and sequenced after tamoxifen are an appropriate option for adjuvant endocrine therapy for most postmenopausal patients with hormone-responsive breast cancer. The incidence of some side effects such as endometrial cancer, stroke, or pulmonary embolism associated with tamoxifen is decreased. Monitoring and management of bone loss associated with AI treatment are essential and are being addressed in ongoing trials. Further studies with longer follow-up are required to clarify the effects of AIs on lipid metabolism and cardiovascular health.

Effect of an aromatase inhibitor on bmd and bone turnover markers: 2-year results of the Anastrozole, Tamoxifen, Alone or in Combination (ATAC) trial (18233230)

Aromatase inhibitors reduce estrogen levels in postmenopausal women with breast cancer. Residual estrogen is an important determinant of bone turnover. Adjuvant anastrozole was associated with significant BMD loss and increased bone remodeling, whereas tamoxifen reduced bone marker levels.

INTRODUCTION

In the Anastrozole, Tamoxifen, Alone or in Combination (ATAC) trial after a median follow-up of 68 months, a significant improvement in disease-free survival was observed with anastrozole treatment (hazard ratio [HR], 0.87; 95% CI, 0.78-0.97; p = 0.01). Anastrozole was also associated with tolerability benefits compared with tamoxifen, but with higher fracture rates. The HR of anastrozole compared with tamoxifen after 60 months of treatment was 1.49 (95% CI, 1.25-1.77).

MATERIALS AND METHODS

This prospectively designed subprotocol (n = 308) of ATAC assessed changes in BMD and bone turnover markers in postmenopausal women with invasive primary breast cancer receiving anastrozole 1 mg/day, tamoxifen 20 mg/day, or combination treatment with both agents for 5 years. Patients with osteoporosis were excluded (osteopenia permitted at the investigators discretion). Lumbar spine and total hip BMD was assessed at baseline and after 1 and 2 years; bone turnover markers (serum C-telopeptide, urinary N-telopeptide [NTX], free deoxypyridinoline, serum procollagen type-1 N-propeptide, bone alkaline phosphatase [ALP]) were assessed at baseline and after 3, 6, and 12 months. Results were expressed as median percentage change.

RESULTS

After 2 years of anastrozole treatment, BMD was lost at lumbar spine (median 4.1% loss) and total hip (median 3.9% loss) sites; increases of 2.2% and 1.2%, respectively, were observed with tamoxifen. After 1 year of anastrozole treatment, increased bone remodeling was observed (NTX, +15%; 95% CI, 3-25%; bone ALP, +20%; 95% CI, 14-25%); decreased bone remodeling was observed with tamoxifen (NTX, -52%; 95% CI, -62% to -33%; bone ALP, -16%; 95% CI, -24% to -11%).

CONCLUSIONS

Anastrozole is associated with significant BMD loss and a small increase in bone turnover, whereas tamoxifen (and the combination) is associated with increased BMD and decreased remodeling. These data may explain the increased fracture risk observed with anastrozole treatment in the ATAC trial. The impact of anastrozole on bone should be weighed against its overall superior efficacy and tolerability as observed in the main ATAC trial.

Defining the role of aromatase inhibitors in the adjuvant endocrine treatment of early breast cancer

BACKGROUND

Over the past few years, data have been published concerning the relative efficacy and safety profiles of tamoxifen and the aromatase inhibitors (AIs) in the adjuvant therapy setting for women with early hormone receptor-positive breast cancer. Recently, debate has centred around trials which have studied primary tamoxifen and AI therapy, switching and sequencing strategies and extended adjuvant therapy.

METHODS

Here, a group of 24 breast cancer experts review efficacy and safety data from the recent major trials investigating tamoxifen and the third-generation AIs in postmenopausal women, which have challenged the perception of tamoxifen as optimum adjuvant endocrine therapy. Data from the Arimidex, Tamoxifen, Alone or in Combination (ATAC) trial, Breast International Group (BIG) 1-98 study, National Cancer Institute of Canada MA 17 trial, Intergroup Exemestane Study (IES), Italian Tamoxifen Anastrozole (ITA) trial, Austrian Breast and Colorectal Cancer Study Group (ABCSG) Trial 8 and Arimidex-Nolvadex (ARNO) 95 are considered to provide a rational interpretation of the impact of these data on current practice, and to highlight areas where further investigation is needed.

CONCLUSION

We can be confident that AIs represent superior adjuvant endocrine treatment to tamoxifen in postmenopausal women, either as initial therapy or as an alternative for women who have started adjuvant therapy with tamoxifen. However, there remain issues regarding the best way to use AIs, such as the optimal length of AI treatment and how a sequence of tamoxifen followed by an AI compares with AI monotherapy; these will require further data to resolve.

Bisphosphonates and osteonecrosis of the jaw: cause and effect or a post hoc fallacy?

BACKGROUND

An increasing amount of reports are being published suggesting a relationship between the use of bisphosphonates (BPs) and the development of osteonecrosis of the jaw (ONJ). We reviewed the currently available evidence and explore the potential mechanisms of action based on the known effects of the concerned BP.

DESIGN

The MEDLine, Current Contents and Science Citation Index Expanded databases were queried and the results augmented by analyzing cited references and recent congress proceedings.

RESULTS

22 papers were included detailing 225 patients, all based on retrospective chart review without control groups. The prevalence of ONJ was estimated at 1.5%. The involved BPs were pamidronate, zoledronic acid, alendronate and risedronate, all potent nitrogen-containing agents. The most common symptom was pain (81.7%), although 12.2% of cases were asymptomatic. In 69.3% of patients ONJ was preceded by a dental extraction. At the time of diagnosis, 74.5% of patients were receiving chemotherapy and in 38.2% of cases corticosteroids were administered. Although various conservative and surgical treatment modalities were reported, residual sites of ONJ persisted in 72.5% of cases.

CONCLUSION

Although not enough evidence is available to prove a causal link, it seems that under specific circumstances local defenses can become overwhelmed resulting in ONJ.

Bone-Directed Treatments for Prostate Cancer

Maintaining bone health in men who have advanced prostate cancer is an important goal of therapy. Low bone mass is prevalent in men who have prostate cancer, and long-term androgen deprivation therapy causes additional significant decreases in bone mineral density. The adverse effects of the disease and current treatment modalities on bone health are further compounded when patients develop bone metastases,which cause clinically significant skeletal morbidity. Treatment with bone-directed therapies, including intravenous bisphosphonates, radio-nuclides, and endothelin-1 antagonists, can provide palliative and therapeutic benefits for patients who have established bone metastases, and treatment with intravenous bisphosphonates may prevent the development of bone metastases.

Cancer-treatment-induced bone loss, part 1

PURPOSE

The pathophysiology, frequency, sequelae, diagnosis, and treatment of cancer-treatment-induced bone loss (CTIBL) are discussed.

SUMMARY

CTIBL is a long-term complication associated with cancer therapies that can directly or indirectly affect bone metabolism. Although CTIBL can occur in any patient receiving a cancer therapy known to cause bone loss, CTIBL is most common in patients with breast or prostate cancer who receive chemotherapy, hormone therapy, or surgical castration, as these can cause hypogonadism and induce bone loss. CTIBL causes bone fragility and an increased susceptibility to fractures; therefore, prevention, early diagnosis, and treatment of CTIBL are essential to decrease the risk of fracture. Bone loss occurs more rapidly and tends to be more severe in patients with CTIBL compared with those with normal age-related bone loss. Fractures of the hip, vertebra, and wrist are the fractures most commonly associated with bone loss. CTIBL is diagnosed by measuring bone mass using bone densitometry. Treatment of CTIBL consists of changing diet and lifestyle such as optimizing calcium and vitamin D intake, exercising, modifying behaviors known to increase the risk of CTIBL and pharmacologic therapy with hormone replacement therapy (HRT), selective estrogen-receptor modifiers (SERMs), calcitonin, or a bisphosphonate.

CONCLUSION

Early identification and treatment of CTIBL are essential to prevent fractures. Patients should be instructed to optimize calcium and vitamin D intake, exercise regularly, and modify lifestyle behaviors known to cause bone loss. Patients with CTIBL should be treated with an oral or i.v. bisphosphonate; SERMs or HRT may be an option in some patients if contraindications do not exist.

Bone integrity and bone metastases in breast cancer

Individuals with a history of early-stage breast cancer may be at increased risk of osteoporosis related to adjuvant therapy, and those with metastatic breast cancer may experience skeletal-related complications from the cancer affecting the bone. Maintaining bone strength is critical in the care of both early- and late-stage breast cancer patients because fractures are associated with morbidity and mortality. This article reviews the maintenance of bone integrity in women with breast cancer.

Adjuvant Hormonal Therapy in Peri‐ and Postmenopausal Breast Cancer

Tamoxifen has been the mainstay of endocrine treatment for early-stage breast cancer in both premenopausal and postmenopausal women for many years. Since 2001, the results of several large, randomized, clinical trials have provided evidence that aromatase inhibitor (AI) therapy, either upfront or in sequence after tamoxifen, improves disease-free survival and, in certain patients, overall survival for postmenopausal patients with hormone receptor-positive breast cancer. Thus far, with relatively short-term follow-up, AIs have been generally safe and well tolerated among the population of patients treated in these adjuvant trials. However, important side effects such as musculoskeletal and bone-related problems, including the risk for osteoporosis and fractures, remain of concern and warrant continued monitoring and follow-up. Several questions regarding the appropriate AI to use and the timing of AI therapy remain unresolved, and ongoing studies will help address these issues. Caution is warranted in the use of AIs in perimenopausal women, including those that develop chemotherapy-induced amenorrhea, and clinical evidence supports the role for AI use in postmenopausal women only. Areas of active investigation include the mechanisms of resistance to endocrine therapy with tamoxifen and AIs and clinical strategies to overcome this resistance.

Cost effectiveness of bisphosphonates in the management of breast cancer patients with bone metastases

BACKGROUND

Bisphosphonates are recommended to prevent skeletal related events (SREs) in patients with breast cancer and bone metastases (BCBM). However, their clinical and economic profiles vary from one agent to the other.

MATERIALS AND METHODS

Using modeling techniques, we simulated from the perspective of the UK's National Health Service (NHS) the cost and quality adjusted survival (QALY) associated with five commonly-used bisphosphonates or no therapy in this patient population. The simulation followed patients into several health states (i.e. alive or dead, experiencing an SRE or no SRE, and receiving first or second line therapy). Drugs costs, infusion costs, SREs costs, and utility values were estimated from published sources. Utilities were applied to time with and without SREs to capture the impact on quality of life.

RESULTS

Compared to no therapy, all bisphosphonates are either cost saving or highly cost-effective (with a cost per QALY < or = 6126 pounds sterlings). Within this evaluation, zoledronic acid was more effective and less expensive than all other options.

CONCLUSIONS

Based on our model, the use of bisphosphonates in breast cancer patients with bone metastases should lead to improved patient outcomes and cost savings to the NHS and possibly other similar entities.

Intravenous ibandronate does not affect time to renal function deterioration in patients with skeletal metastases from breast cancer: phase III trial results

As patients with metastatic bone disease typically receive long-term treatment with bisphosphonates, and often antineoplastic compounds, drug-related safety is of considerable importance. Clinical trial data for intravenous (i.v.) ibandronate suggest that its nephrotoxic potential is comparable with placebo. We conducted a post hoc Kaplan-Meier analysis of time to serum creatinine increase with i.v. ibandronate throughout 2 years of treatment. After 96 weeks, 12% of patients in the placebo group and 6% in the ibandronate 6 mg group (ns, P = 0.22) had defined serum creatinine increases. After 12 treatment months (48 weeks), 4% of patients receiving placebo and 2% of patients receiving ibandronate 6 mg showed increased serum creatinine. These results suggest that there is no clinically relevant change in serum creatinine levels with i.v. ibandronate 6 mg infused every 3-4 weeks for 2 years. Comparative trials to examine the renal safety of ibandronate and other i.v. bisphosphonates are warranted.

Bisphosphonate-associated osteonecrosis: a long-term complication of bisphosphonate treatment

We present current knowledge of bisphosphonate-associated osteonecrosis, a new oral complication in oncology. It was first described in 2003, and hundreds of cases have been reported worldwide. The disorder affects patients with cancer on bisphosphonate treatment for multiple myeloma or bone metastasis from breast, prostate, or lung cancer. Bisphosphonate-associated osteonecrosis is characterised by the unexpected appearance of necrotic bone in the oral cavity. Osteonecrosis can develop spontaneously or after an invasive surgical procedure such as dental extraction. Patients might have severe pain or be asymptomatic. Symptoms can mimic routine dental problems such as decay or periodontal disease. Intravenous use of pamidronate and zoledronic acid is associated with most cases. Other risk factors include duration of bisphosphonate treatment (ie, 36 months and longer), old age in patients with multiple myeloma, and a history of recent dental extraction. We also discuss pathobiology, clinical features, management, and future directions for the disorder.

Management of the adverse effects associated with intravenous bisphosphonates

Intravenous bisphosphonates are widely used to treat hypercalcemia and to reduce skeletal-related morbidity among cancer patients. However, serious complications, generally occurring in less than 2% of patients participated in phase III clinical trials, including acute systemic inflammatory reaction, ocular inflammation, renal failure, nephrotic syndrome, electrolyte imbalance, and osteonecrosis of the maxilla and mandible have all been increasingly reported. Yet, strategies to deal with these complications are becoming clear. Acute systemic inflammatory reaction is often self-limited and becomes less intense during subsequent treatments. For patients who develop ocular symptoms, prompt ophthalmologic evaluation is crucial to determine the safety of a subsequent bisphosphonate therapy. Patients who receive long-term pamidronate should be evaluated at intervals for early sign of nephritic syndrome as timely cessation of the agent may result in a full recovery. To reduce the risk of severe electrolyte abnormalities, particularly hypocalcemia, correcting any pre-treatment electrolyte abnormality and supplementing vitamin D and calcium may be helpful. Finally, to reduce the risk of osteonecrosis of the maxilla and mandible, obtaining a full dental evaluation before treatment and avoidance of invasive dental procedures is suggested. The three commonly used intravenous bisphosphonates (pamidronate, zoledronic acid, and ibandronate), are generally safe; ibandronate has to date been the least reported to be associated with renal side effects. As clinical indications of intravenous bisphosphonates continue to expand, prescribing clinicians should be familiar with these possible adverse effects and discuss them with patients before commencing or continuing on therapy.

Medical malpractice in the age of technology: how specialty societies can make a difference

In the United States, medical malpractice litigation, and the rising cost of malpractice insurance, is a crisis that threatens to restrict patient access to high-risk services, especially obstetrics and certain surgical procedures. Radiation Oncology, though a small specialty, is very technologically oriented. Because the history of product liability and malpractice litigation in this country parallels the technologic revolution, practitioners of this specialty are clearly at risk for litigation. Because legislative relief is unlikely to be forthcoming in the near future, many specialty societies have assumed the responsibility for devising means to protect members from frivolous law suits, without compromising a patient's right to due process. To date, Radiation Oncology societies have not taken a leadership role in this movement, preferring instead to cede this responsibility to the American College of Radiology. Opportunities exist for specialty societies to define standards of care and establish guidelines for expert witness testimony. To date, the courts have been supportive of these efforts. Herein, we summarize some of the salient issues of the malpractice crisis facing Radiation Oncology and offer suggestions for change within the specialty to better address the malpractice problem.

Extended breast cancer treatment with an aromatase inhibitor (Letrozole) after tamoxifen: why, who and how long?

Breast cancer remains a leading cause of cancer death in women worldwide, and the risk for disease recurrence continues despite improvements in screening and treatment and the use of prophylactic estrogen-inhibiting therapies such as tamoxifen. A number of long-term studies now indicate a significant risk for breast cancer recurrence among patients who have undergone the currently recommended five years of tamoxifen adjuvant therapy following successful treatment of their initial disease. This ongoing recurrence risk extends even to patients commonly considered at low risk for relapse, that is, those with low-grade, small tumors, and/or node-negative disease. Treatment with tamoxifen for more than five years appears detrimental rather than beneficial and, therefore, tamoxifen is not indicated for use beyond the initial five years. Endometrial cancer and thromboembolism are among the serious adverse events that have been observed with long-term tamoxifen treatment. The aromatase inhibitors are able to reduce overall estrogen levels and appear to be better tolerated over a long term. Letrozole is the most potent aromatase inhibitor and has been available in Europe since 1996 and in the United States since 1997. Letrozole has been approved for first-line treatment of postmenopausal women with hormone-receptor-positive or hormone-receptor-unknown, advanced or metastatic breast cancer in the United States and Europe, as well as for neoadjuvant treatment (primary systemic therapy) of early breast cancer prior to surgery in many countries. The results of the pivotal MA-17 trial demonstrate that letrozole is unique in its ability to improve disease-free survival in breast cancer patients who have undergone tamoxifen therapy for five years. The MA-17 results indicate that extended adjuvant therapy with letrozole reduces risk of recurrence in this setting by 42%, reduces risk of distant recurrence (metastasis), and may improve patient survival in the node-positive patient population. The results also show letrozole to be well tolerated and safe over the length of follow-up. The trial outcomes have led to the approval of letrozole for the extended adjuvant indication in more than 40 countries worldwide. Re-randomization of letrozole-treated patients from this pivotal trial is underway to investigate if ten years of extended adjuvant endocrine therapy leads to further improvement, and the results of this extension study should aid in resolving several open questions regarding extended adjuvant therapy, including who should be treated and for how long.

Management of Cancer-Treatment–Induced Bone Loss in Postmenopausal Women Undergoing Adjuvant Breast Cancer Therapy: A Z-FAST Update

The prevention of cancer-treatment-induced bone loss (CTIBL) in long-term adjuvant breast cancer therapy is a high priority. Postmenopausal women with cancer, already at increased risk of bone loss because of age-related estrogen deficiency, face accelerated bone loss with the use of estrogen-depleting therapies such as third-generation aromatase inhibitors (AIs). Although effective in reducing cancer recurrence rates in the adjuvant setting, AIs are associated with bone loss and an increased risk of fractures. Bisphosphonates, which act by inhibiting osteoclastic bone resorption, have been shown to increase bone mineral density (BMD) and reduce fracture risk in postmenopausal women with established osteoporosis. Furthermore, the potent bisphosphonate zoledronic acid has been shown to be efficacious in reducing bone loss in premenopausal women receiving combination adjuvant hormone therapy (goserelin, a gonadotropin-releasing hormone agonist, plus either an AI or tamoxifen). The use of zoledronic acid to prevent CTIBL in postmenopausal women receiving adjuvant AI therapy with letrozole is currently being investigated in the Zometa/Femara Adjuvant Synergy Trial (Z-FAST). Postmenopausal women with stage I-IIIa estrogen-receptor-positive and/or progesterone-receptor-positive breast cancer starting letrozole are randomized to receive either upfront zoledronic acid or delayed zoledronic acid. At 6 months, assessable women in the upfront group showed a mean increase of 1.55% in lumbar spine (L1 - L4) BMD, compared with a mean decrease of 1.78% in women in the delayed group, resulting in a difference of 3.33% between groups; moreover, women in the former group showed a mean increase of 1.02% in total hip BMD, compared with a mean decrease of 1.40% in those in the latter group, resulting in a significant difference of 2.42% between groups (P <.001). Thus, the Z-FAST BMD results show that upfront zoledronic acid prevents CTIBL in postmenopausal women receiving adjuvant letrozole therapy for early breast cancer. Combining the anticancer efficacy of letrozole with the bone-protective effect of zoledronic acid may be a successful treatment in this setting.

Physiologic aspects of aging: impact on cancer management and decision making, part II

In this second article of our two-part review, we focus on age-associated physiologic changes involving the nervous, endocrine, hematologic, immune, and musculoskeletal systems, with close attention to the interconnected nature of these systems. There is a well-known connection between the neuroendocrine and immune systems via the hypothalamic-pituitary-adrenal axis and via interaction by means of cytokines, hormones, and neurotransmitters. These changes may lead to a loss of integration and resiliency with age, thus decreasing the ability of the elderly patient with cancer to adapt to stressful circumstances. Prominent changes include decline in memory and cognition, and increased susceptibility to peripheral neuropathy. Hematologic and immune changes like reduced bone marrow reserve and increased susceptibility to infections have far reaching implications for cancer care in the elderly. Gradual decline in hormone levels, and changes in muscle and body composition, can lead to functional decline and frailty. Use of the clinical interventions suggested in this article, along with an appreciation of the interplay of these age-related physiologic changes and their consequences, allows oncology professionals to customize therapy and minimize side effects in the geriatric oncology patient.

Effects of third-generation aromatase inhibitors on bone

Low oestradiol levels in women are associated with decreased bone mineral density (BMD) and increased fracture risk. The third-generation aromatase inhibitors (AIs; anastrozole, letrozole, and exemestane) are used in the treatment of early and advanced breast cancer and act by substantially reducing oestrogen synthesis in postmenopausal women. However, due to their mechanism of action, there is concern regarding the long-term effects of these agents on bone, particularly when used in the adjuvant setting. In this paper, the currently available data on the effects of the third-generation AIs on markers of bone turnover, BMD, and fracture risk are reviewed, with the emphasis on results in the adjuvant treatment of early breast cancer. These data suggest that both the steroidal (exemestane) and non-steroidal (anastrozole and letrozole) AIs appear to affect bone turnover. Conclusions regarding any clinically relevant differences between these agents are difficult to make, and further data are awaited from long-term adjuvant use of these three agents in ongoing clinical studies. Postmenopausal women are at increased risk of osteoporosis and fracture, and the increasing use of AIs in the adjuvant treatment of postmenopausal breast cancer patients will require appropriate consideration of fracture risk, with the use of anti-osteoporotic therapies, if necessary.

Adjuvant endocrine therapy for postmenopausal women with early breast cancer

Results from multiple clinical trials involving aromatase inhibitors have added to the knowledge base relating to endocrine therapy of postmenopausal women with hormone receptor-positive early breast cancer. In the extended adjuvant setting, data from the Austrian Breast and Colorectal Cancer Study Group 6a trial showed an advantage for anastrozole following 5 years of tamoxifen treatment, consistent with the more robust MA.17 trial that examined letrozole versus placebo following 5 years of tamoxifen treatment. The combined analysis of the Austrian Breast and Colorectal Cancer Study Group 8 trial and the German Arimidex Nolvadex 95 trial, plus the Italian Tamoxifen Anastrozole trial, have shown the advantage of switching to anastrozole over continuing the tamoxifen to complete the full 5 years of adjuvant therapy. These trials support the previously reported larger and double-blind Intergroup Exemestane Study. The Arimidex, Tamoxifen, Alone or in Combination trial now has data out to 68 months of median follow-up showing the maintenance of a significant advantage of anastrozole over tamoxifen for disease-free survival. In this initial treatment setting, the Breast International Group 1-98 trial recently showed a significant advantage for letrozole over tamoxifen. The current debate is centered on whether the optimal strategy is to give an aromatase inhibitor initially or after several years of tamoxifen treatment. Multiple important questions remain, including the predictive value of molecular markers such as progesterone receptor, the optimal duration of aromatase inhibitor therapy, the long-term adverse effects, and the relative efficacy and toxicity of the different aromatase inhibitors.

Too Much, Too Little, Too Late to Start Again? Assessing the Efficacy of Bisphosphonates in Patients with Bone Metastases from Breast Cancer

The diagnosis of bone metastases can be a devastating occurrence for any woman with breast cancer. In this setting, bone metastases can result in skeletal-related events (SREs) such as pathologic fracture, spinal cord compression, and hypercalcemia. Several trials have confirmed the ability of bisphosphonates to reduce or delay these skeletal complications, and they should now be considered standard care for these women. The analysis of SREs is the typical primary end point in bisphosphonate studies. While not undermining their importance, the definition of SREs does not include complications important to patients, such as pain and immobility. It is these symptoms that are most frequently reported by patients, and bone pain and quality of life (QoL) are often measured as secondary end points in these trials. Bone pain and QoL measures are not standardized and are difficult to compare among patient populations. We do not yet know the true efficacy of bisphosphonates as analgesics or how they impact QoL. This paper reviews the current efficacy measures used in recent bisphosphonate trials and discusses their benefits and limitations. It also explores the role of bone biomarkers and their potential use in monitoring treatment response.

Current management of treatment-induced bone loss in women with breast cancer treated in the United Kingdom

New therapeutic options in breast cancer have improved survival but consequently increase the relevance of late complications. Ovarian suppression/ablation and aromatase inhibitors (AI) in the adjuvant setting have improved outcome, but have clinically important adverse effects on bone health. However, investigation and management of cancer treatment-induced bone loss (CTIBL) is poorly defined with no national guidance. In 2004, a questionnaire was sent to over 500 breast surgeons and oncologists who treat breast cancer within the United Kingdom. The questionnaire evaluated access to bone densitometry and specialist expertise as well as attitudes to investigation of CTIBL and anticipated changes in the use of AI for postmenopausal early breast cancer. A total of 354 completed questionnaires were received, 47 from clinicians not currently treating breast cancer. Of the 307 evaluable questionnaires, 164 (53%) were from breast surgeons, 112 (36%) from clinical oncologists and 31 (10%) from medical oncologists. Although most respondents recognised that CTIBL was the responsibility of the treating breast team, investigations for CTIBL are limited even though most had adequate access to bone densitometry; 98 (32%) had not requested a DXA scan in the last 6 months and 224 (73%) had requested fewer than five scans. In all, 235 (76%) were not routinely investigating patients on AI for bone loss. A total of 277 (90%) felt that their practice would benefit from national guidelines to manage these patients, and the majority (59%) had little or no confidence in interpreting DXA results and advising on treatment. This questionnaire has highlighted clear deficiencies in management of CTIBL in early breast cancer. The development of national guidelines for the management of these patients and educational initiatives for breast teams are urgently required.

Osteonecrosis of the jaw in cancer after treatment with bisphosphonates: incidence and risk factors

PURPOSE

Osteonecrosis of the jaw (ONJ) has been associated recently with the use of pamidronate and zoledronic acid. We studied the incidence, characteristics, and risk factors for the development of ONJ among patients treated with bisphosphonates for bone metastases.

PATIENTS AND METHODS

ONJ was assessed prospectively since July 2003. The first bisphosphonate treatment among patients with ONJ was administered in 1997. Two hundred fifty-two patients who received bisphosphonates since January 1997 were included in this analysis.

RESULTS

Seventeen patients (6.7%) developed ONJ: 11 of 111 (9.9%) with multiple myeloma, two of 70 (2.9%) with breast cancer, three of 46 (6.5%) with prostate cancer, and one of 25 (4%) with other neoplasms (P = .289). The median number of treatment cycles and time of exposure to bisphosphonates were 35 infusions and 39.3 months for patients with ONJ compared with 15 infusions (P < .001) and 19 months (P = .001), respectively, for patients with no ONJ. The incidence of ONJ increased with time to exposure from 1.5% among patients treated for 4 to 12 months to 7.7% for treatment of 37 to 48 months. The cumulative hazard was significantly higher with zoledronic acid compared with pamidronate alone or pamidronate and zoledronic acid sequentially (P < .001). All but two patients with ONJ had a history of dental procedures within the last year or use of dentures.

CONCLUSION

The use of bisphosphonates seems to be associated with the development of ONJ. Length of exposure seems to be the most important risk factor for this complication. The type of bisphosphonate may play a role and previous dental procedures may be a precipitating factor.

Optimizing the use of aromatase inhibitors in adjuvant therapy for postmenopausal patients with hormone-responsive early breast cancer: current and future prospects

PURPOSE

Five years of tamoxifen treatment after primary surgery has had a significant impact on outcomes for women with early breast cancer, but the third-generation aromatase inhibitors (AIs) are now challenging tamoxifen as the gold standard endocrine adjuvant treatment. Results from two large, phase III, early adjuvant studies have indicated that the AIs letrozole and anastrozole offer greater protection against recurrence than tamoxifen in upfront substitution strategies in the first 5 years after surgery. Similarly, changeover to an AI (exemestane or anastrozole) after 2-3 years of tamoxifen has been shown to offer greater protection against recurrence than 5 years of tamoxifen. More than 50% of early breast cancer recurrences occur five or more years after surgery. Letrozole has been shown to offer greater protection against recurrence than placebo in the 5 years after a standard course of tamoxifen. The safety implications of treatment with these potent AIs for 5 years or more are being closely monitored. Anticipated effects of estrogen deprivation on bone health may be treatable with bisphosphonates, and this strategy is under investigation. Effects on the cardiovascular system, and other estrogen-sensitive systems such as the central nervous system, are currently unclear and further results are awaited.

CONCLUSION

Current evidence indicates that the third-generation AIs will improve outcomes for many women with early breast cancer.

Improving bone health in patients with early breast cancer by adding bisphosphonates to letrozole: The Z-ZO-E-ZO-FAST program

Women undergoing treatment for breast cancer often have a number of pre-existing risk factors for bone loss, including existing or induced postmenopausal status. Long-term anticancer treatments may further augment this risk, inducing further bone-loss, increasing the incidence of bone fractures, associated morbidity and mortality, and healthcare costs. Long-term treatment with third-generation antiaromatase agents (AAAs) is used more and more instead of or after the selective estrogen-receptor modulator tamoxifen for the adjuvant treatment of postmenopausal women with breast cancer. These AAAs include anastrozole, letrozole, and exemestane, and all are superior to tamoxifen in both efficacy and safety. In particular, they reduce the incidence of serious adverse events such as thromboembolism and endometrial cancer that are associated with tamoxifen treatment. On the other hand, the AAAs lead to profound estrogen depletion and appear to have a pronounced effect on bone mineral density (BMD), and a significantly higher incidence of osteoporosis/osteopenia and bone fracture has been reported in some trials. Bisphosphonate therapies, including zoledronic acid (ZA), have emerged as a promising means of reducing bone loss associated with antiaromatase therapy. Several large, randomized, multicenter trials are underway to determine whether upfront or delayed ZA therapy can decrease BMD losses in patients undergoing treatment with the antiaromatase agent letrozole (Z-FAST; ZO-FAST, and E-ZO-FAST), and early results from the Zometa-Femara adjuvant synergy trial (Z-FAST) trial indicate a significant benefit of upfront ZA therapy compared with delayed ZA therapy. Forthcoming results from all these trials should determine whether ZA could be used to improve bone heath in women undergoing adjuvant therapy with AAAs for breast cancer.

Bisphosphonates for malignancy-related bone disease: current status, future developments

This review relates to the efficacy and safety of bisphosphonates in metastatic bone disease. It discusses practical recommendations and possible future indications for bisphosphonate therapy. The current aims of bisphosphonates for metastatic bone disease are to prevent skeletal-related events (SREs), reduce bone pain and improve quality of life. Phase III clinical trials of clodronate and pamidronate have established their efficacy against bone complications in patients with breast cancer and multiple myeloma, while randomized trials have shown SRE reductions with zoledronic acid in patients with breast cancer and multiple myeloma, prostate cancer, and lung and other solid tumors. These bisphosphonates also have some effect on metastatic bone pain. Ibandronate is a new aminobisphosphonate, available in more than 40 countries outside of the US as intravenous and oral formulations for the prevention of skeletal events in patients with breast cancer and bone metastases. Phase III studies have shown that both intravenously and orally administered ibandronate have efficacy for the prevention of skeletal events and for the reduction of metastatic bone pain. In addition to efficacy, the long-term tolerability of bisphosphonates in metastatic bone disease influences drug selection. Besides their use in patients with established bone metastases, recent and ongoing research suggests that bisphosphonates also have clinical benefit in the adjuvant setting, and for the treatment of cancer-treatment-induced bone loss. Such interesting new developments may underpin a new era of bisphosphonate use sometime in the near future.

Renal safety and efficacy of i.v. bisphosphonates in patients with skeletal metastases treated for up to 10 Years

INTRODUCTION

Bisphosphonates (BPs) delay the onset or reduce the incidence of skeletal complications in patients with bone metastases. However, there are few data on the renal safety and activity of i.v. BPs beyond 2 years of administration.

MATERIALS AND METHODS

We retrospectively analyzed serum creatinine (SCr) levels and skeletal-related events (SREs) in cancer patients receiving i.v. BPs for >or= 24 months. All patients received 90 mg pamidronate every 3-4 weeks. Pre- and post-treatment SCr levels and the peak levels attained were recorded. A notable SCr increase was defined as: an increase >0.5 mg/dl for patients with baseline SCr <1.4 mg/dl; an increase >1 mg/dl for patients with baseline SCr >1.4 mg/dl; or doubling over baseline. The following parameters were also analyzed: the proportion of patients with at least one SRE, the distribution of each type of SRE, the time to first SRE, and the skeletal morbidity rate (SMR).

RESULTS

Fifty-seven patients with bone metastases resulting from breast cancer (BC) (n = 48), multiple myeloma (n = 7), renal cell carcinoma (n = 1), and prostate cancer (n = 1) were evaluated. The median age at the start of treatment was 57 years (range, 27-81); 25% of the patients were >70 years old. Forty-three patients received pamidronate then switched to zoledronic acid. The median overall duration of BP administration was 34 months (range, 24+ to 131+), with a median duration of zoledronic acid therapy of 25 months (range, 2-40). Twenty-seven of 48 BC patients received different chemotherapy regimens (median number of lines, 2; range, 1-6). The median SCr levels were: baseline, 0.82 mg/dl (range, 0.4-1.4); time of analysis, 0.89 mg/dl (0.4-2); highest level, 1.0 mg/dl (0.5-2). A notable SCr increase was observed in seven patients (12.2%; all grade 1). Twenty-six patients (45.6%) experienced SREs after starting BP treatment. The median time to first SRE was 911 days (95% confidence interval, 731; 1,023). The SMR was 0.20 events per year. Ten patients ceased treatment because of: an SCr level of 2 mg/dl (n = 1) physician decision (n = 6) and jaw osteonecrosis (n = 3). Ten patients died of progressive disease.

CONCLUSION

i.v. BPs are safe and active during prolonged treatment administration, and renal function is maintained in patients receiving multiple cytotoxic therapies. Jaw osteonecrosis occurred in 5% of the study population, and its causal relationship with BP treatment requires further observation and study.

Long-term prevention of skeletal complications by pamidronate in a patient with bone metastasis from endometrial carcinoma: a case report

INTRODUCTION

Bisphosphonates are an effective treatment for bone metastases from breast cancer. However, it is unclear whether they are effective for bone metastases from endometrial carcinoma.

CASE

A 70-year-old woman previously treated for endometrial carcinoma was referred to our hospital due to osteolytic destruction of the left ischial tuberosity. Technetium-99m-HMDP bone scintigraphy revealed abnormal uptake in the ischium. Biopsy revealed a metastatic bone tumor, but computed tomography scans did not show general metastatic spread. The patient received intravenous administration of pamidronate and three cycles of chemotherapy (epirubicin + paclitaxel + carboplatin). Three years later, the bone lesion showed prominent sclerotic changes with no evidence of disease recurrence radiologically.

CONCLUSION

Pamidronate may prevent skeletal complications in selected patients with bone metastasis due to endometrial carcinoma.

The first pamidronate containing polymer and copolymer

Here we report the synthesis, characterization and hydrogelation of polymers consisting of pamidronate, a useful therapeutic agent.

Long-Term Safety of Intravenous Ibandronic Acid for Up to 4 Years in??Metastatic Breast Cancer

BACKGROUND AND OBJECTIVE

Despite their widespread use in metastatic bone disease, some bisphosphonate drugs are associated with adverse events (AEs), particularly renal toxicity, adding to treatment burdens and increasing healthcare costs. Ibandronic acid is a single-nitrogen bisphosphonate with high efficacy against bone events and metastatic bone pain, and a renal safety profile compar- able to that of placebo. In this study, the safety of ibandronic acid was examined over a period of 4 years.

PATIENTS AND METHODS

During an initial 96-week period, breast cancer patients with bone metastases were randomised in double-blind fashion to placebo or ibandronic acid 6mg administered by intravenous infusion over 1-2 hours every 3-4 weeks as part of a previously reported phase III trial (MF 4265 study). All patients completing the phase III trial were offered open-label active treatment for a further 96 weeks (extension phase). A total of 62 patients received ibandronic acid 6mg in this extension phase and were classified according to their initial treatment (placebo/ibandronic acid 6mg [placebo/6mg] and ibandronic acid 6mg/ibandronic acid 6mg [6mg/6mg] groups). Safety was assessed by AE reports and clinical laboratory evaluations.

RESULTS

During the 4-year study, most patients experienced at least one AE, with malignancy progression being most commonly reported. However, fewer treatment-related AEs were reported in the extension phase (placebo/6mg: 6.3% [1/16]; 6mg/6mg: 13.0% [6/46]) than in the initial phase of the study (placebo: 56.3% [9/16]; 6mg: 67.4% [31/46]). Serious AEs were mainly due to malignancy progression. There were no clinically relevant renal AEs, and in both groups, serum creatinine levels were similar for up to 4 years.

CONCLUSION

This 96-week open-label safety extension of a phase III, placebo-controlled trial demonstrates that long-term use of intravenous ibandronic acid is well tolerated.

Bisphosphonates as adjuvant therapy for breast cancer

Great strides have been made over the last 20 years in the treatment of breast cancer and despite an increasing incidence, the number of deaths has fallen sharply since the late 1980s. The advent of new therapies, including taxanes and aromatase inhibitors, and exciting results announced recently using trastuzumab in the adjuvant treatment of HER2-positive patients should decrease this even further. However, although most patients present with disease that appears to be localized to the breast, a significant proportion of women will eventually develop metastatic breast cancer. Therefore, the detection and treatment of micrometastatic disease represents perhaps the most important remaining challenge in breast cancer management, and is the focus of extensive ongoing research. Bone is the most frequent site of distant relapse, accounting for approximately 40% of all first recurrences. In addition to the well recognized release of bone cell-activating factors from the tumor, it is now appreciated that the release of bone-derived growth factors and cytokines from resorbing bone can attract cancer cells to the bone surface and facilitate their growth and proliferation. Bisphosphonates are potent inhibitors of bone osteolysis and the inhibition of bone resorption could therefore have an effect on the development and progression of metastatic bone disease. They could represent an adjuvant therapeutic strategy of potential importance. Clinical trial results with the early bisphosphonate, clodronate, have proved inconclusive. A large, randomized, controlled trial has recently completed accrual and should provide the definitive answer to the question of the role of clodronate in this setting. More potent second- and third-generation bisphosphonates have also shown enhanced antitumor effects in preclinical evaluation and further studies are required to determine whether this antitumor potential of bisphosphonates translates to the clinical setting. Adjuvant bisphosphonates are, therefore, currently only recommended in the research setting and clinical trials evaluating the adjuvant use of these newer compounds are currently recruiting or being established. This article will review in more detail the rationale for the adjuvant use of bisphosphonates, the results of early trials, the progress of the later trials and the potential future role of bisphosphonates in the adjuvant treatment of breast cancer. In addition, it is increasingly acknowledged that many cancer treatments have detrimental effects on bone and can increase the risk of fracture. The increasing use of aromatase inhibitors, in particular, will become a major cause of treatment-induced bone loss. This bone loss can be prevented with bisphosphonate treatment and this will also be discussed.

Ibandronic Acid

Ibandronic acid (Bondronat) is a potent, new-generation, nitrogen-containing bisphosphonate, available in both intravenous and oral formulations, which effectively inhibits osteoclast-mediated bone resorption. In clinical trials, the two formulations were equally effective in preventing skeletal-related events and improving quality of life in patients with bone metastases of breast cancer. Both intravenous and oral ibandronic acid reduced metastatic bone pain scores below baseline levels for up to 2 years. Oral ibandronic acid is administered as a single 50 mg tablet taken once daily. It suppressed bone resorption in breast cancer patients with bone metastases to an extent similar to that observed with intravenous zoledronic acid. Both intravenous and oral ibandronic acid were well tolerated with no evidence of renal toxicity. Ibandronic acid is therefore a valuable addition to the bisphosphonates used in the treatment of bone metastases of breast cancer, offering high potency and the convenience of oral administration, combined with the absence of renal toxicity.

Osteonecrosis of the jaws in periodontal patients with a history of bisphosphonates treatment

BACKGROUND/AIM

Osteonecrosis of the jaws is being increasingly reported in patients with bone metastasis from a variety of solid tumours and disseminated multiple myeloma receiving intra-venous bisphosphonates. The signs and symptoms that may occur before the appearance of clinical evident osteonecrosis include changes in the health of periodontal tissues, non-healing mucosal ulcers, loose teeth and unexplained soft-tissue infection. A series of nine periodontally involving patients showing osteonecrosis of the jaws that appeared following the intra-venous use of bisphosphonates is reported.

MATERIAL AND METHODS

Nine consecutive patients with osteonecrosis of the jaws were prospectically studied. Patients' past medical histories and the drugs that they had received for their malignant disease were systematically documented. Clinical, histopathological and radiographic features and proposal for treatment modalities of osteonecrosis are also reported.

RESULTS

Of the nine patients (six women and three men) observed, all had osteonecrosis in the mandible; two had maxillary involvement as well. All nine patients had a history of extraction of periodontally hopeless teeth preceding the onset of osteonecrosis. In two patients, the lesions also appeared in edentulous areas spontaneously. All the patients had received intra-venous bisphosphonates as treatment for their disseminated haematological neoplasms or metastatic bone disease. The duration of bisphosphonate therapy at presentation ranged from 10 to 70 months (median: 33 months).

CONCLUSIONS

Jaw osteonecrosis appears to be associated with the intra-venous use of bisphosphonates. Dental professionals should be aware of this potentially serious complication in periodontal patients receiving long-term treatment with bisphosphonates.

Managing the care of patients with bisphosphonate-associated osteonecrosis

BACKGROUND

This position paper addresses the prevention of bisphosphonate-associated osteonecrosis (BON) and the management of care of patients with cancer and/or osteoporosis who are receiving bisphosphonates and who have BON or are at risk of developing it.

METHODS

The authors reviewed the literature available on this newly described oral complication. Information of interest included bisphosphonates, the medications associated with this oral complication; the patient population at risk of developing BON and the diseases being treated with this class of medications; the clinical presentation of the oral lesions; guidelines for managing the care of patients who develop BON; the prevention of this complication based on current knowledge; and recommendations for routine dental treatment of patients receiving bisphosphonates.

RESULTS

There is strong evidence that bisphosphonate therapy is the common link in patients with BON. The pathobiological mechanism leading to BON may have to do with the inhibition of bone remodeling and decreased intraosseous blood flow caused by bisphosphonates. People at risk include patients with multiple myeloma and patients with cancer metastatic to bone who are receiving intravenous bisphosphonates, as well as patients taking bisphosphonates for osteoporosis. The risk of developing complications appears to increase with time of use of the medication. There are no guidelines based on evidence, and the clinical management of the oral complication is based on expert opinion.

CONCLUSION

Prevention of BON is the best approach to management of this complication. Existing protocols to manage the care of patients who will receive radiation therapy or chemotherapy may be used until specific guidelines for BON are developed.

Extended adjuvant endocrine therapy of early breast cancer

Women who are diagnosed with early breast cancer remain at considerable risk of recurrence over the next several decades, even if their tumors were small and lymph nodes were negative, and despite receiving standard adjuvant therapy. A majority of breast cancers are hormone (estrogen) receptor-positive and amenable to endocrine therapy, and for those women five years of the selective estrogen receptor modulator tamoxifen is standard therapy. Longer treatment of node-negative patients with tamoxifen may reduce survival benefits, however, possibly due to tamoxifen resistance and emerging receptor agonist activity of that drug. Aromatase inhibitors, which indirectly prevent estrogen stimulation of breast cancer by suppressing whole-body estrogen synthesis in post-menopausal women, are being investigated as alternative, or complementary, therapy to adjuvant tamoxifen in those women: as an alternative to five years of tamoxifen, sequenced with two to three years of tamoxifen, or following five years of tamoxifen. The strategy to extend the benefits of adjuvant therapy beyond a standard course of tamoxifen, using the aromatase inhibitor letrozole, was explored in a large trial, MA.17. Compared with women who received placebo, those who were treated with letrozole experienced a significant 43% reduction in their residual risk of recurrence. This effect was seen regardless of nodal status. Based on the long-term risk of most women with early breast cancer and the MA.17 trial results, the extended adjuvant letrozole may benefit many of those women who are disease-free after five years of tamoxifen. This review is based on a literature search of databases including MEDLINE/PubMed, San Antonio Breast Cancer Symposium, and the Annual Meeting of the American Society of Clinical Oncology, up to and including August 2005, with information selected for its relevance to adjuvant therapy of breast cancer with endocrine therapy only.