INCIDENCE OF SKELETAL COMPLICATIONS IN PATIENTS WITH BONE METASTATIC PROSTATE CANCER AND HORMONE REFRACTORY DISEASE: PREDICTIVE ROLE OF BONE RESORPTION AND FORMATION MARKERS EVALUATED AT BASELINE

The impact of osteoporosis in men treated for prostate cancer

Prostate cancer patients are at significant risk for SREs, with up to 50% of androgen-insensitive patients experiencing an SRE at 24 months. The risk increases with the duration and type of cancer treatment. SREs decrease HRQOL, increase the cost of care, and are associated negatively with overall survival. Screening men at greatest risk (slender white men and men with hormone refractory disease or metastatic disease) with BMD measurements, and initiating empiric therapy (vitamin D3, calcium, parenteral estrogens, bisphosphates) may be warranted.

Effects of gonadotropin-releasing hormone agonists on bone metabolism markers and bone mineral density in patients with prostate cancer

OBJECTIVES

To better understand bone metabolism and predict bone loss in treatment using gonadotropin-releasing hormone agonist for patients with prostate cancer.

METHODS

The changes in bone mineral density and blood levels of bone metabolism markers and the level of pyridinoline cross-linked carboxy-terminal telopeptide of type I collagen, a specific marker of bone resorption, and carboxy-terminal pro-peptide of human type I procollagen, a specific marker of bone formation, were examined in 27 consecutive patients with prostate cancer without bone metastasis.

RESULTS

After 2 years of gonadotropin-releasing hormone treatment, the bone mineral density was significantly lower (median 0.937 g/cm2) than before treatment. Pyridinoline cross-linked carboxy-terminal telopeptide of type I collagen began to increase significantly 6 months after the start of treatment (3.0 to 8.3 ng/mL, median 4.6, at baseline versus 3.4 to 8.2 ng/mL, median 5.2, after 6 months). Carboxy-terminal pro-peptide of human type I procollagen began to show a significant rise 1 year after the start of treatment (from 72.8 to 221.5 ng/mL, median 102.0, at baseline to 82.7 to 293.4 ng/mL, median 132.0, at 1 year).

CONCLUSIONS

Functional coupling between bone resorption and formation was noted, and a decrease in bone mass, even in men, owing to androgen deficiency, was biochemically demonstrated. Fluctuations in these two bone metabolism markers preceded the decrease of bone mineral density. Therefore, these markers might be a predictor of bone loss.

Cost-effectiveness of zoledronic acid for the prevention of skeletal complications in patients with prostate cancer

PURPOSE

We estimated the cost-effectiveness of zoledronic acid vs placebo for decreasing skeletal complications in men with prostate cancer.

MATERIALS AND METHODS

We performed a cost-effectiveness analysis alongside a multinational clinical trial of zoledronic acid. Cost estimation was based on prospectively collected resource use data for 85.3% of enrolled patients. Cost-effectiveness ratios were based on within-trial data on clinical outcomes, quality of life and study medication cost.

RESULTS

Patients receiving zoledronic acid experienced fewer hospital days during a mean followup of 9 months (average 5.6 vs 8.0 days; p = 0.1910). Mean direct costs excluding study medication were US dollars 5365 for patients receiving zoledronic acid and US dollars 5689 for patients receiving placebo, a difference of US dollars 324 (95% CI US dollars 1781 to US dollars 1146). The global average cost of zoledronic acid plus its administration during the trial was US dollars 5677 (US dollars 450 per dose). The nominal cost per skeletal complication avoided was US dollars 112300 (95% CI US dollars 6900 to US dollars 48700) and the cost per additional patient free of skeletal complications was US dollars 51400 (95% CI US dollars 26900 to US dollars 243700). Nominal within-trial cost per quality adjusted life-year was US dollars 159200, which varied widely in sensitivity analyses.

CONCLUSIONS

The nominal base case estimate of the cost per quality adjusted life-year for zoledronic acid in the prevention of skeletal complications of prostate cancer is consistent with that of bisphosphonates in breast cancer. However, the cost-effectiveness ratios for bisphosphonates are higher than commonly cited thresholds for conferring cost-effectiveness.

Bisphosphonates to Prevent Skeletal Complications in Men With Metastatic Prostate Cancer

PURPOSE

The literature on clinical trials of bisphosphonates in men with metastatic prostate cancer is reviewed to familiarize the reader with biology of bone metastases and rationale for use of bisphosphonates.

MATERIALS AND METHODS

A MEDLINE review of the literature on prostate cancer and bisphosphonates was performed.

RESULTS

In uncontrolled clinical trials bisphosphonates improved pain and analgesic scores in men with symptomatic bone metastases. In a randomized controlled trial of men with bone metastases and progressive disease after first line hormonal therapy zoledronic acid decreased the skeletal related events, a composite end point defined as fracture, surgery or radiation therapy to bone, or change in antineoplastic therapy for bone pain. Randomized controlled trials with other bisphosphonates reported no significant benefit in men with bone metastases. Problems with the study populations, drug bioavailability and potency, statistical power and end point definition may have contributed to the negative results of these other studies.

CONCLUSIONS

Zoledronic acid decreases the risk of skeletal related events in men with bone metastases and disease progression after first line hormonal therapy. Additional clinical research is needed to evaluate the optimal timing, schedule and duration of bisphosphonate treatment in men with metastatic prostate cancer. Additional research is also necessary to determine whether bisphosphonates can prevent bone metastases in men with high risk nonmetastatic prostate cancer.

Prostate cancer and bone metastases: medical treatment

Prostate cancer is the most common malignancy in men in the United States. With the long natural history of the disease, management of skeletal morbidity related to advanced prostate cancer becomes a major public health issue. The standard of care in advanced prostate cancer is androgen deprivation therapy. This may accelerate the development of osteoporosis and further exacerbate the risks of having adverse skeletal-related events develop. Recently, the use of bisphosphonates in men who have not responded to androgen deprivation therapy has been shown to reduce the incidence of skeletal-related events with time. Questions remain as to whether bisphosphonates should be broadly applied to earlier stages of the disease or tailored to men at higher risk of having bone-related morbidity. Work is ongoing to improve other approaches to the medical treatment of bone metastases in patients with advanced prostate cancer including the use of radiopharmaceuticals and combined chemotherapy.

Metastatic prostate cancer: complications and treatment

Despite highly successful treatments for localized prostate cancer, approximately 35% to 40% of men will eventually experience a detectable rise in serum prostate specific antigen. A portion of these men will go on to experience clinically expressed extracapsular disease, with as many as two-thirds having evidence of bone involvement. Diagnosis of skeletal involvement involves serum markers of disease progression and radiological evaluation. Skeletal-related events are numerous and include bone pain, spinal cord compression, vertebral collapse, and pathological fractures. Current treatments for advanced prostate cancer include individual or combined hormonal therapies, chemotherapy, radiotherapy, surgical treatments, and most recently, antiresorptive medications.

Nitrogen containing bisphosphonates induce apoptosis and inhibit the mevalonate pathway, impairing Ras membrane localization in prostate cancer cells

PURPOSE

Metastasis to bone is an important cause of morbidity in advanced prostate cancer. Despite the typically sclerotic nature of prostatic bone metastases osteolysis has a significant role in the pathogenesis of this disease. The nitrogen containing bisphosphonates (N-BPs), such as pamidronate and zoledronic acid, have greatly enhanced potency for inhibiting bone resorption and inducing apoptosis in osteoclasts. We investigated the effects of N-BPs on prostate cancer cells.

MATERIALS AND METHODS

Cell viability was determined with an MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymeyhoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) dye reduction assay. Cell cycle analysis, DNA fragmentation and caspase 3 activity were assessed using flow cytometry. Ras, Bcl-2 and Bax were quantified by Western blotting.

RESULTS

Pamidronate and zoledronic acid decreased cell viability in the 3 human cell lines DU145, PC3 and LNCaP. These effects were associated with changes in cell cycle distribution, induction of DNA fragmentation and a decrease in the Bcl-2-to-Bax ratio, which are features of apoptotic cell death. Pre-incubation with caspase inhibitors attenuated the effects of zoledronic acid and caspase 3 activity was demonstrated in treated DU145 cells. Zoledronic acid induced loss of cell viability in DU145 cells was prevented by co-treatment with farnesol, suggesting that N-BPs cause inhibition of the mevalonate pathway and Ras prenylation. A decrease in active, membrane bound Ras in zoledronic acid treated DU145 cells was shown by Western blot analysis.

CONCLUSIONS

N-BPs induce apoptosis in prostate cancer via a caspase dependent mechanism. They have effects on protein prenylation via inhibition of the mevalonate pathway and impair membrane localization of Ras in prostate cancer cells.

Background to and management of treatment-related bone loss in prostate cancer

Prostate cancer is a common disease among older men. Androgen suppression by either orchiectomy or administration of luteinising hormone-releasing hormone (LHRH) analogues is the mainstay of treatment. Since the use of prostate-specific antigen (PSA) serum testing has become widespread, however, the timing of endocrine therapy has expanded considerably to include patients with limited involvement of extraprostatic sites and patients presenting an isolated elevation of PSA after radical treatments. These patients are expected to be treated for a long time, since they have a rather low risk of disease progression and there is no recommended time limit for LHRH analogue therapy. The long-term adverse effects of androgen deprivation therapy, therefore, deserve more attention than they have received in the past. Osteoporosis represents a special concern for men with prostate cancer receiving androgen deprivation therapy. The rate of bone loss in these men seems to markedly exceed that associated with menopause in women, and fractures occur more frequently than in the healthy elderly male population. Serial bone mineral density (BMD) evaluation could allow the detection of patients with prostate cancer who are at greater risk of osteoporosis and adverse skeletal events after androgen deprivation therapy, such as patients already osteopenic or osteoporotic at baseline and men with rapid bone loss during treatment. BMD evaluated during treatment could also be a potential surrogate parameter of antiosteoporotic therapeutic efficacy. Treatment of bone loss induced by androgen deprivation comprises general prevention measures, antiosteoporotic drugs and the use of alternative endocrine therapies. Optimising lifestyle and diet is important, although it cannot completely prevent bone loss. Patients with nonsevere bone disease may benefit from calcium and vitamin D supplements. Men who are osteoporotic before androgen deprivation or men becoming osteoporotic during treatment and/or experiencing adverse skeletal events may also require bisphosphonates. The effectiveness of these drugs in preventing fractures has been shown in a single randomised study involving patients with osteoporosis, but it has not yet been established in a prostatic cancer population without bone metastases given androgen deprivation therapy. Different forms of endocrine therapy such as low-dose estrogens, antiandrogens and intermittent androgen ablation are under investigation. They could offer the advantage of avoiding (or limiting) treatment-related bone loss. In our opinion, however, the data available so far are not robust enough to recommend these alternative endocrine therapies instead of standard androgen deprivation in routine clinical practice.

Clodronate for treatment of bone metastases in hormone refractory prostate cancer

INTRODUCTION

Approximately 85% of patients who die from prostate cancer have bone metastases. Even though the radiological aspect of such metastases is osteoblastic, we currently know that these lesions are mixed, with coexisting blastic and lytic lesions, always beginning with bone lysis by osteoclast proliferation. Treatment options are palliative and have poor response, and when there is an improvement it is usually short-lived. This work intends to study the effect of clodronate in the treatment of skeletal complications of prostate cancer.

MATERIALS AND METHODS

In an open prospective study 32 patients with hormone refractory prostate cancer with metastases to bones were assessed, in the period between November 2000 and September 2002. Mean age was 69 years (51 to 83 years). Patients were previously assessed by a pain scale and Karnofsky index. They underwent bone scintigraphy, X-ray, dosage of prostate specific antigen (PSA) and biochemical tests before and following treatment (administration of intravenous clodronate every 28 days). The Student's t-test was used for statistical analysis.

RESULTS

Twenty-nine patients (90.6%) showed improvement after the first and the 2nd cycles, which persisted for at least 4 months. Average on the pain scale improved from 7.7 to 2.1 and Karnofsky index raised from 42 to 71. Radiological aspect of the metastases improved in 15 patients (46.8%) and side effects were low (only 2 patients - 6.2%).

CONCLUSION

Bisphosphonate was effective in the treatment of skeletal complications of prostate cancer, presenting an objective response in 90.6% of treated patients, with a marked improvement in the pain scale, Karnofsky index and consequently in the quality of life of patients, and with low side effects.

Management of Vertebral Metastases in Prostate Cancer: A Retrospective Analysis in 119 Patients

The objectives of this study were to define clinical problems and treatment strategies in vertebral metastases of prostate cancer. The clinical files of 634 patients with prostate cancer seen in a comprehensive cancer center during a 4-year period were retrospectively reviewed. One hundred nineteen patients (18.8%) had 212 significant episodes of osseous spinal metastases. Pain was nearly universal (93%), and motor and bladder impairment occurred in 25% and 3.1% of patients, respectively. Bone scan and magnetic resonance imaging (MRI) were performed in 197 and 64 episodes, respectively. Fifteen episodes of spinal cord compression were treated surgically. Other treatments included hormonal therapy (163 episodes), chemotherapy (70 episodes), and radiation therapy (103 episodes). Osteolytic lesions were observed alone and in combination with osteoblastic pattern in 18% and 26% of episodes, respectively. Bone scan was the most effective screening procedure of vertebral involvement, and MRI effectively showed epidural involvement. Overall treatment led to improvements in pain and motor impairment in 77% and 50% of patients, respectively. However, clinical episodes were recurrent (1.78 episodes per patient; range, 1-8). Median survival after vertebral metastasis episode was 14 months compared with only 4 months after surgery for spinal cord compression. Vertebral metastases strongly alter quality of life in patients with prostate cancer. Pain and neurologic complications are the major problems. Careful early screening with bone scan and MRI may help to define better treatment strategy. However, further prospective studies of clinical management are needed to determine the optimal timing of radiation therapy, medical treatments, and surgery.

Pathophysiology of bone metastases from prostate cancer and the role of bisphosphonates in treatment

Metastasis to bone is a common feature in advanced prostate cancer patients. Current treatments, while effective in suppressing tumour growth and relieving tumour associated bone pain, do not provide long term remission or 'cure' for the disease. A greater understanding of prostate cancer metastasis is required if new treatment strategies are to be developed. Growth of tumour foci in skeletal sites is a major cause of morbidity in advanced prostate cancer and has required the development of specialised approaches to treatment, including the use of bisphosphonates. These drugs inhibit tumour induced osteoclastic bone resorption, thereby preventing skeletal related events and treatment induced bone loss. Zoledronic acid is currently the only bisphosphonate with proven benefit in prostate cancer. Bisphosphonates may also modify the bone microenvironment so that it becomes less favourable for the growth and survival of metastases. The most recent developments in our understanding of the advantages for growth and survival gained by metastatic prostate cancer cells in the skeleton are reviewed, along with the clinical evidence supporting the use of bisphosphonates in advanced prostate cancer.

The role of bisphosphonates in the management of metastatic prostate cancer

Most men with advanced prostate cancer have primarily skeletal metastases, which are responsible for most of the morbidity and mortality of prostate cancer. Although bone lesions are osteoblastic in radiographic appearance, recent evidence has demonstrated that anti-osteoclast therapy with bisphosphonates reduces skeletal-related complications in hormone-refractory prostate cancer. This observation may be explained by the demonstration that osteoclast activity is greatly upregulated even in osteoblastic metastases. Furthermore, androgen deprivation therapy, the mainstay of treatment for advanced prostate cancer, leads to increased bone resorption and reduces bone mineral density. These effects can be ameliorated, and potentially completely prevented, by coadministration of bisphosphonates. These findings may point to a role for bisphosphonates in men with prostate cancer even prior to the development of skeletal metastases. Determination of whether such early therapy ultimately results in delayed time to skeletal progression or in improved survival will require large randomized studies.

Therapeutic benefit of bisphosphonates in the management of prostate cancer-related bone disease

A diversity of bone pathology is present in men with prostate cancer. Androgen deprivation therapy (ADT) can cause significant and progressive osteopoenia and osteoporosis. Bone is also the primary site for metastases leading to associated pain, skeletal fractures and hypercalcaemia. Bisphosphonate therapy decreases bone resorption, which may prevent or reverse loss of bone mineral density. Both pamidronate and zoledronic acid have proven efficacy in preventing ADT-induced bone loss. In a randomised, placebo-controlled trial, in men with hormone-refractory prostate cancer, there was a decreased incidence of skeletal- related adverse events in men receiving zoledronic acid. So far, randomised trials have failed to show improved pain control. Formalised guidelines are needed to help clinicians decide which patients should be treated with bisphosphonates, when to initiate therapy and for what duration.

Radioisotopic treatment of bone pain from metastatic prostate cancer

Hormone-refractory prostate cancer patients with painful bony metastatic lesions are potential candidates for bone-seeking radiopharmaceutical therapies. After careful assessment of symptoms and localization of pain, a bone scan is the single most useful imaging modality for the clinician to assess patients for the presence and distribution of osteoblastic lesions. Increased uptake (compatible with bony metastases) on a conventional bone scan is currently a prerequisite for treating patients with a bone-targeted therapeutic isotope. Determining whether metastatic bony involvement is focal or diffuse is also important in the clinical decision-making process. Patients with multifocal metastatic disease are excellent candidates for systemic therapies, whereas patients with unifocal metastatic disease may be more appropriate candidates for focal therapies such as external-beam radiation. Patients who are poorly tolerant of narcotics should be actively considered for alternative treatments such as systemic radiopharmaceuticals. Contraindications to administration of current bone-seeking radioisotopes include substantial degrees of renal insufficiency or bone marrow suppression.

The potential role of bisphosphonates in prostate cancer

Skeletal morbidity secondary to metastases and osteoporosis is common in patients with advanced prostate cancer. Despite the typically sclerotic nature of prostate cancer metastases, osteoclast mediated osteolysis may play a significant role. This review addresses the newly recognised antitumour effects of bisphosphonates in addition to their role in inhibiting osteoclast mediated bone resorption. Both preclinical and clinical evidence of a role for bisphosphonates in the treatment and prevention of bone metastases secondary to prostate cancer is assessed.

Costs of prostate cancer, metastatic to the bone, in the Netherlands

OBJECTIVE

To quantify medical costs associated with bone metastases in patients with prostate cancer. Bone metastases in patients with prostate cancer are associated with considerable morbidity, negatively impact quality of life, and can add substantially to medical costs, given a median survival of 30-35 months from diagnosis of bone metastases.

METHODS

A retrospective cost analysis from both a community and university hospital in The Netherlands was conducted. Twenty-eight patient records (14 from each hospital) were investigated to assess the impact of skeletal-related events (SREs), including fractures, spinal cord compression, and radiotherapy, on total direct medical costs and cost of hospitalization. Costs are given in EUROS (Euros).

RESULTS

The average total cost of treatment was Euros 13,051 per patient over the 24-month follow-up period, which includes an average cost of Euros 6973 per patient to treat SREs. Treatment of SREs more than doubled total treatment costs. Patients in this analysis experienced, on average, one SRE per year, and the cost of SREs varied from Euros 1187 to Euros 40,948.

CONCLUSIONS

Occurrence of SREs contributes significantly to the cost of care for patients with advanced prostate cancer. These data suggest that bisphosphonates, which can reduce pain and SREs, may reduce healthcare costs.

Suppression of prostate cancer induced bone remodeling by the endothelin receptor A antagonist atrasentan

PURPOSE

We examined the effects of atrasentan (endothelin-A receptor antagonist) on bone deposition and resorption markers and on bone scan index.

MATERIALS AND METHODS

This double-blind, randomized, placebo controlled clinical trial of hormone refractory prostate cancer patients was done at 74 medical centers in the United States and Europe. A total of 288 asymptomatic patients with hormone refractory prostate adenocarcinoma and evidence of metastatic disease were randomized to 1 of 3 treatment groups, namely 2.5 mg. atrasentan, 10 mg. atrasentan or placebo administered orally daily until disease progression. The main outcomes measures were changes in bone deposition markers (total alkaline phosphatase and bone alkaline phosphatase) and bone resorption (N-telopeptides, C-telopeptides and deoxypyridinoline), and in the bone scan index.

RESULTS

At baseline markers of bone deposition and resorption were elevated 1.4 to 2.7-fold above respective upper limits of normal. Subjects receiving placebo experienced a 58% elevation in mean total alkaline phosphatase and a 99% elevation in mean bone alkaline phosphatase (p < 0.001), whereas subjects receiving 10 mg. atrasentan maintained stable mean total alkaline phosphatase and bone alkaline phosphatase values compared with baseline. N-telopeptides, C-telopeptides and deoxypyridinoline elevation from baseline were consistently less in patients receiving 10 mg. atrasentan compared with placebo. Similar trends were observed in subjects who received 2.5 mg. atrasentan. Changes in clinical bone scan studies paralleled bone marker changes.

CONCLUSIONS

Atrasentan suppressed markers of biochemical and clinical prostate cancer progression in bone and demonstrates clinical activity for hormone refractory prostate cancer.

Cathepsin K mRNA and protein expression in prostate cancer progression

Prostate cancer (CaP) is the most commonly diagnosed malignancy in men and is often associated with bone metastases, which cause much of the morbidity associated with CaP. Lesions associated with CaP generally exhibit increased bone formation and resorption. Increased bone resorption may release factors from the extracellular matrix that contribute to tumor growth. Cathepsin K (cat K) is a cysteine protease that exhibits strong degradative activity against the extracellular matrix and is involved in osteoclast-mediated bone destruction. In this study, we analyzed the expression of cat K in CaP cell lines and patient samples. Cat K message was detected in CaP cell lines by reverse transcription-polymerase chain reaction (RT-PCR) and in primary CaP and metastases by in situ hybridization. Immunohistochemistry revealed variable expression of cat K in primary CaP samples, as well as nonosseous metastases, whereas expression in bone metastases was significantly higher than in primary CaP, and normal prostate tissues were negative. Cat K protein was detected in CaP cell lines by Western blotting after immunoprecipitation. Cat K enzymatic activity was also detected in CaP cell lines by a fluorogenic assay and by an assay for degradation of collagen type I. Increased levels of NTx, a marker of bone matrix degradation mediated primarily by cat K, were also detected in sera of patients with CaP bone metastases. We hypothesize that CaP-expressed cat K may contribute to the invasive potential of CaP, while increased expression in bone metastases is consistent with a role in matrix degradation.

Zoledronic acid is superior to pamidronate for the treatment of bone metastases in breast carcinoma patients with at least one osteolytic lesion

BACKGROUND

Treatment with zoledronic acid (Zol) was compared with a dose of 90 mg of pamidronate (Pam) in breast carcinoma (BC) patients with at least 1 osteolytic lesion based on data from a Phase III, randomized trial.

METHODS

Overall, 1130 patients with breast carcinoma who had all types of bone metastases (osteolytic, mixed, or osteoblastic by radiology) were randomized to receive treatment with either 4 mg of Zol or 8 mg of Zol as a 15-minute infusion or 90 mg of Pam as a 2-hour infusion every 3-4 weeks for 12 months. A skeletal-related event (SRE) was defined as a pathologic fracture, spinal cord compression, radiotherapy, or surgery to bone.

RESULTS

Among all patients with BC, the proportion of those who had an SRE (primary endpoint) was comparable between treatment groups (43% of patients who received 4 mg of Zol vs. 45% of patients who received Pam). Among patients who had breast carcinoma with at least 1 osteolytic lesion (n = 528 patients), the proportion with an SRE was lower in the 4-mg Zol group compared with the Pam group (48% vs. 58%), but this did not reach statistical significance (P = 0.058). The time to first SRE was significantly longer in the 4-mg Zol group compared with the Pam group (median, 310 vs. 174 days; P = 0.013). Moreover, multiple-event analysis demonstrated significant further reductions in the risk of developing SREs over the reduction achieved with Pam (30% in the osteolytic subset [P = 0.010] and 20% for all patients with BC [P = 0.037]).

CONCLUSIONS

The current data indicate that treatment with 4 mg of Zol was more effective than 90 mg of Pam in reducing skeletal complications in a subset of patients with breast carcinoma who had at least 1 osteolytic lesion at study entry.

The new bisphosphonate, Zometa (zoledronic acid), decreases skeletal complications in both osteolytic and osteoblastic lesions: a comparison to pamidronate

Bisphosphonates are the treatment of choice for lytic bone lesions associated with breast cancer. In contrast, bone lesions associated with prostate cancer are predominately osteoblastic. Zoledonic acid (Zol) is a new-generation bisphosphonate that is approximately 2-3 orders of magnitude more potent than pamidronate (Pam) in preclinical models and has demonstrated clinical efficacy in patients with both lytic and blastic lesions. Zoledonic acid (4 mg via 15 min infusion) every 3-4 weeks was directly compared to Pam (90 mg via 2 hr infusion) in 767 patients with breast cancer and bone metastases. The primary endpoint was the proportion of patients experiencing a skeletal-related event (SRE) over 13 months. Zoledonic acid was as effective as Pam, and the proportion of Zol-treated patients with an SRE (42% in the hormonal therapy strata and 44% in the chemotherapy strata) was comparable to the original studies comparing Pam to placebo. Among 371 breast cancer patients receiving hormonal therapy, the proportion of patients with an SRE was 47% for Pam vs. 57% for placebo (P = 0.057), and among 380 patients treated with chemotherapy, the proportions with an SRE were 43% for Pam vs. 56% for placebo (P = 0.008) at 12 months. Zoledronic acid (4 mg) has been compared to placebo in a randomized Phase III trial involving 422 men with hormone-refractory prostate cancer metastatic to bone. Zoledonic acid demonstrated a significant advantage over placebo for median time to first SRE (median not reached for Zol vs. 321 days for placebo; P = 0.011), the proportion of patients with an SRE over 15 months (33 vs. 44% for placebo; P = 0.021), and mean skeletal morbidity rate (number of SREs/time, 0.08 vs. 1.49 for placebo; P = 0.006). In addition, the effects of Zol were apparent early. At 3 months, only 12% of Zol-treated patients had an SRE vs. 23% for placebo (P = 0.003), and at 6 months, the proportions were 21 vs. 31% for placebo (P = 0.025). In contrast, a previous study of Pam in 236 prostate cancer patients found that Pam was no more effective than placebo in reducing bone pain or SREs over 6 months. In these studies, Zol was well tolerated with a safety profile similar to other IV bisphosphonates. In conclusion, Zol is the first bisphosphonate to demonstrate efficacy in both lytic and blastic disease. The unique properties of this novel agent should be further explored in future clinical trials.

Zoledronic Acid Significantly Reduces Pathologic Fractures in Patients with Advanced-Stage Prostate Cancer Metastatic to Bone

The skeletal complications of metastatic bone disease secondary to advanced prostate cancer result in significant morbidity. In particular, pathologic fractures often require clinical intervention and are independent predictors of mortality in men with advanced prostate cancer. Before the introduction of zoledronic acid, bisphosphonates had been shown to provide pain palliation in patients with prostate cancer and bone metastases but were not efficacious in preventing skeletal complications. Zoledronic acid is the first bisphosphonate to show efficacy in reducing skeletal complications associated with the predominantly osteoblastic bone lesions characteristic of prostate cancer. In a large phase III randomized trial, zoledronic acid 4 mg every 3 weeks for 15 months significantly reduced the percentage of men who experienced a skeletal complication and reduced the incidence of pathologic fractures. Additionally, zoledronic acid 4 mg significantly decreased the annual incidence of skeletal complications, including fractures, and provided better control of bone pain compared with placebo. Adverse events with zoledronic acid were primarily limited to the flu-like, acute-phase symptoms previously reported with intravenous bisphosphonates, namely fever, myalgia, nausea, and anemia. These adverse events were mild to moderate and easily managed with supportive care. Zoledronic acid is the first and only bisphosphonate shown to reduce skeletal morbidity, including fractures, in patients with advanced prostate cancer and bone metastases.

Broad clinical activity of zoledronic acid in osteolytic to osteoblastic bone lesions in patients with a broad range of solid tumors

Bone metastases are a common feature of a variety of solid tumors and are associated with substantial skeletal morbidity, including severe bone pain and pathologic fractures. Treatment with bisphosphonates, primarily pamidronate, is the current standard of care for patients with breast cancer and multiple myeloma who have predominantly osteolytic lesions. However, until recently no bisphosphonate had demonstrated efficacy in patients with osteoblastic lesions, which are common during the progression of prostate cancer and other solid tumors. Zoledronic acid, a potent, new-generation, nitrogen-containing bisphosphonate, has demonstrated significant benefits for patients with bone metastases resulting from a broad range of primary tumors, including multiple myeloma and breast, lung, kidney, and prostate cancers, and other solid tumors. Benefits include a decreased incidence of pathologic fractures and longer time to the first skeletal complication. Zoledronic acid is the first and only bisphosphonate to be proved effective in patients with all types of bone lesions, from osteolytic to osteoblastic, and therefore represents an important therapeutic advancement in the treatment of bone metastases.

A randomized, placebo-controlled trial of zoledronic acid in patients with hormone-refractory metastatic prostate carcinoma

BACKGROUND

Bone metastases are a common cause of morbidity in patients with prostate carcinoma. We studied the effect of a new bisphosphonate, zoledronic acid, which blocks bone destruction, on skeletal complications in prostate cancer patients with bone metastases.

METHODS

Patients with hormone-refractory prostate cancer and a history of bone metastases were randomly assigned to a double-blind treatment regimen of intravenous zoledronic acid at 4 mg (N = 214), zoledronic acid at 8 mg (subsequently reduced to 4 mg; 8/4) (N = 221), or placebo (N = 208) every 3 weeks for 15 months. Proportions of patients with skeletal-related events, time to the first skeletal-related event, skeletal morbidity rate, pain and analgesic scores, disease progression, and safety were assessed. All statistical tests were two-sided.

RESULTS

Approximately 38% of patients who received zoledronic acid at 4 mg, 28% who received zoledronic acid at 8/4 mg, and 31% who received placebo completed the study. A greater proportion of patients who received placebo had skeletal-related events than those who received zoledronic acid at 4 mg (44.2% versus 33.2%; difference = -11.0%, 95% confidence interval [CI] = -20.3% to -1.8%; P =.021) or those who received zoledronic acid at 8/4 mg (38.5%; difference versus placebo = -5.8%, 95% CI = -15.1% to 3.6%; P =.222). Median time to first skeletal-related event was 321 days for patients who received placebo, was not reached for patients who received zoledronic acid at 4 mg (P =.011 versus placebo), and was 363 days for those who received zoledronic acid at 8/4 mg (P =.491 versus placebo). Compared with urinary markers in patients who received placebo, urinary markers of bone resorption were statistically significantly decreased in patients who received zoledronic acid at either dose (P =.001). Pain and analgesic scores increased more in patients who received placebo than in patients who received zoledronic acid, but there were no differences in disease progression, performance status, or quality-of-life scores among the groups. Zoledronic acid at 4 mg given as a 15-minute infusion was well tolerated, but the 8-mg dose was associated with renal function deterioration.

CONCLUSION

Zoledronic acid at 4 mg reduced skeletal-related events in prostate cancer patients with bone metastases.

Bisphosphonates: their evolving role in the management of prostate cancer-related bone disease

PURPOSE OF REVIEW

The use of androgen deprivation therapy has increased because of its use as part of multimodality therapy for high-risk early stage disease and in recurrent nonmetastatic disease. Hormonal therapy is associated with secondary osteoporosis and increased skeletal morbidity. Furthermore, in patients with established bone metastases, osseous complications are a significant problem. Bisphosphonates have been investigated in the prevention of bone density loss and skeletal morbidity. Results of these studies are now becoming available.

RECENT FINDINGS

Data are emerging that demonstrate that bisphosphonates can prevent skeletal morbidity, such as pathologic fractures and spinal cord compression in men with hormone-refractory prostate cancer. The early use of bisphosphonates has also been shown to prevent bone loss due to androgen deprivation therapy. Current third-generation bisphosphonates are several hundred times more potent than their predecessors. Evidence is emerging that these drugs not only inhibit bone resorption but also are cytotoxic to prostate cancer cells.

SUMMARY

Bisphosphonates are assuming a prominent ancillary role in prostate cancer therapy through their ability to prevent skeletal morbidity. Their potential to interfere with the formation of osseous tumor deposits has lead to investigations into the capacity of these drugs to prevent bone metastasis.

Skeletal fractures negatively correlate with overall survival in men with prostate cancer

PURPOSE

We assessed the correlation of skeletal fracture with survival in men with prostate cancer on chronic androgen suppressive therapy.

MATERIALS AND METHODS

A total of 195 consecutive patients on chronic androgen suppression for prostate cancer were evaluated for the history and type of skeletal fracture. Correlation with overall survival was performed via multivariate analysis.

RESULTS

Of these 195 men 24 reported skeletal fracture since the diagnosis of prostate cancer. Median overall survival was 121 and 160 months in men without and with a history of skeletal fracture since the diagnosis of prostate cancer, respectively (p = 0.04). A history of skeletal fracture was retained as a negative predictor of survival on forward stepwise regression analysis (RR = 7.4, p = 0.007).

CONCLUSIONS

Our results suggest that skeletal fracture in patients with prostate cancer is an independent and adverse predictor of survival. Consideration for screening men at greatest risk via bone mineral density measurements and initiating empirical skeletal therapies (bisphosphonates, estrogens and so forth) may be warranted. This recommendation awaits validation through prospective randomized trials.

Skeletal fracture associated with androgen suppression induced osteoporosis: the clinical incidence and risk factors for patients with prostate cancer

PURPOSE

Limited information exists regarding the long-term risk of skeletal fracture in men on androgen suppression for prostate cancer. In addition, the clinical risk factors predisposing them to skeletal fracture are incompletely defined. We define the long-term risk and clinical risk factors for skeletal fracture in patients with prostate cancer on chronic androgen suppression.

MATERIALS AND METHODS

A total of 181 consecutive patients with prostate cancer on androgen suppression therapy were evaluated. The primary end point was skeletal fracture. Comprehensive demographic information was gathered, and univariate and multivariate analyses were performed to identify associations with skeletal fracture.

RESULTS

The proportion of patients who had survived fracture-free at 5 and 10 years on androgen suppression therapy was 96% and 80%, respectively. The black race (p = 0.009) and increased body mass index (p = 0.024) were identified as protective against androgen suppression associated skeletal fractures. A significant correlation was identified between the duration of androgen suppression and risk of skeletal fracture (p = 0.003).

CONCLUSIONS

Patients with prostate cancer treated with androgen suppression are at risk for skeletal fracture, and risk increases with the duration of therapy. Slender white men are at greatest risk. Conversely, black men and those with body mass indexes greater than normal (greater than 25 kg/m(2)) are at minimal risk despite a prolonged duration (10 years) of androgen suppression.

Pretreatment levels of urinary deoxypyridinoline as a potential marker in patients with prostate cancer with or without bone metastasis

OBJECTIVE

To assess the predictive role of the bone markers alkaline phosphatase (ALP) and urinary deoxypyridinoline (DPD), as indicators of bone turnover, at baseline in patients with prostate cancer.

PATIENTS, SUBJECTS AND METHODS

Urinary DPD, serum ALP and prostate-specific antigen (PSA) were evaluated in 23 patients with benign prostatic hyperplasia (BPH), 115 with prostatic carcinoma, of whom 21 had bone metastasis, and in 16 age-matched control subjects.

RESULTS

Patients with newly diagnosed prostate cancer and bone metastasis had a higher urinary excretion of DPD, and a higher serum PSA and ALP than had patients with BPH and those with prostate cancer but no metastasis. Receiver operating curve analysis for PSA, ALP and DPD showed a significant discriminating ability for positive and negative bone scans (P = 0.0684). However, from logistic regression of the combinations, only serum ALP was a significant independent predictor of bone metastasis in patients with prostate cancer.

CONCLUSION

Serum ALP or urinary DPD are the best predictors of bone metastasis in patients with prostate cancer; further studies with more patients are required.