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

Society of Urologic Oncology position statement: Redefining the management of hormone-refractory prostate carcinoma

Because patients with hormone-refractory prostate carcinoma are a very diverse group, management of these patients represents a unique challenge. Despite much research, to the authors' knowledge few studies published to date have provided definitive treatment answers. The Society of Urologic Oncology (SUO) convened a multidisciplinary panel of urologists, oncologists, and radiation oncologists to develop a treatment algorithm for patients with hormone-refractory prostate carcinoma. The resulting treatment outline was based on a review of the literature review and on the expert opinions of the panelists. The current article provided a logical progression of treatment choices that included hormonal manipulations, chemotherapeutic options, and adjunctive therapies. Future clinical trials and therapies were also discussed by the authors. Management strategies should be targeted toward the individual patient. Although significant progress has been made in understanding and treating hormone-refractory prostate carcinoma, earlier interventions would be ideal and better therapeutic approaches to prolong survival are necessary.

The Emerging Role of Bisphosphonates in Prostate Cancer

Bisphosphonates are a class of therapeutic agents originally designed to treat loss of bone density. It has been shown that the primary mechanism of action is inhibition of osteoclastic activity. Accumulating data show that these drugs are useful in diseases with propensities toward osseous metastases. In particular, they are effective in diseases in which there is clear upregulation of osteoclastic or osteolytic activity such as breast cancer and multiple myeloma. Despite the fact that osseous metastases in prostate cancer manifest as osteosclerosis rather than osteolysis, studies now show that bisphosphonates are useful in the management of this disease. In particular, they have demonstrated an impact on osteoporosis associated with hormonal therapy, bone pain from metastases, and skeleton-related events from prostatic adenocarcinoma. This review briefly summarizes the available clinical data on the utilization of bisphosphonates in the disease of prostate cancer.

Management of Bone Loss in Men With Prostate Cancer

PURPOSE

Bone loss is increasingly recognized as a common occurrence in men receiving androgen deprivation therapy (ADT) for prostate cancer. Skeletal metabolism and osteoporosis in men, assessment of bone mineral density (BMD), effects of ADT on BMD, management strategies and potential therapies for osteopenia or osteoporosis in men with prostate cancer are reviewed.

MATERIALS AND METHODS

Relevant literature is reviewed concerning bone loss and osteoporosis in men with and without prostate cancer, techniques of assessing BMD, data on bone loss and fracture risk and management strategies.

RESULTS

The incidence of osteoporotic fractures usually increases a decade later in men than in women. ADT causes significant loss of BMD, which may hasten the development of osteoporosis. Men who are treated with hormonal therapy for an increasing prostate specific antigen and who may live for many years should have baseline BMD assessments. Osteopenia or osteoporosis should be treated to minimize the risk of osteoporotic fracture. Treatment with zoledronic acid seems appropriate since it has been shown to increase BMD in men treated with ADT and to reduce the rate of skeletal related events in men with early hormone refractory prostate cancer with metastatic disease.

CONCLUSIONS

Monitoring BMD is warranted in men contemplating or receiving ADT but prophylactic therapy to prevent bone loss currently is not recommended. Men with evidence of significant bone loss who are receiving ADT should be treated. Zoledronic acid is a logical choice based on available data.

The patient with hormone-refractory prostate cancer: determining who, when, and how to treat

Hormone-refractory prostate cancer (HRPC) encompasses a wide spectrum of patients, including patients with prostate-specific antigen (PSA)--only disease, those with increasing PSA levels yet stable metastatic disease, and those with increasing PSA levels and objective evidence of progressive metastases. Unfortunately, with the historical lack of effective therapy in this population, the oncologist is faced with few data with which to make difficult clinical decisions. Although our understanding of the biology of androgen independence continues to improve, and our fund of potential therapeutic agents has widened, multiple trial-specific and patient-specific obstacles have contributed to the difficulty in demonstrating clear benefit to therapy. Herein, we will review the biology of androgen-independent prostate cancer, the historical impediments to clinical trials in this population, and the reasons to treat, or not to treat, the patient with HRPC.

Combined Analysis of Two Multicenter, Randomized, Placebo-Controlled Studies of Pamidronate Disodium for the Palliation of Bone Pain in Men With Metastatic Prostate Cancer

Purpose: Bone metastases occur in approximately 80% of patients with advanced prostate cancer. Pain is common in these patients. The purpose of this study was to evaluate the effect of an intravenous bisphosphonate, pamidronate disodium, on pain control in metastatic prostate cancer patients.

Patients and Methods: Two multicenter, double-blind, randomized, placebo-controlled trials were conducted in patients with bone pain due to metastatic prostate cancer, with disease progression after first-line hormonal therapy. Intravenous pamidronate disodium (90 mg) or placebo was administered every 3 weeks for 27 weeks. Efficacy was measured via self-reported pain score (Brief Pain Inventory), analgesic use, the proportion of patients with a skeletal-related event (SRE; defined as pathologic fracture, radiation or surgery to bone, spinal cord compression, or hypercalcemia), and a pilot quantitative measurement of mobility. Laboratory evaluations included serum prostate-specific antigen, interleukin-6, bone alkaline phosphatase, and urinary bone resorption markers.

Results: Results of the two trials were pooled. There were no sustained significant differences between the pamidronate and placebo groups in self-reported pain measurements, analgesic use, proportion of patients with an SRE, or mobility at week 9 or 27. Urinary bone resorption markers were suppressed in the pamidronate group compared with placebo.

Conclusion: Pamidronate disodium failed to demonstrate a significant overall treatment benefit compared with placebo in palliation of bone pain or reduction of SREs. Evaluation of more potent bisphosphonates in patients with prostate cancer is warranted.

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.

Spinal Cord Compression in Metastatic Prostate Cancer

INTRODUCTION

Spinal cord compression (SCC) in metastatic prostate cancer is not rare occurring in 1 to 12% of patients. We have analysed patients treated for this condition in our institution assessing outcome and prognostic factors.

MATERIAL AND METHODS

Retrospective analysis of the notes of 24 patients hospitalised with SCC due to metastatic prostate cancer from 1987 to 2001.

RESULTS

At presentation 3 patients were ambulant with mild neurological deficit, 12 patients were paraparetic and 9 patients were paraplegic. Diagnosis was established by emergency myelogram, CT-scan or MRI of the spine. 8 patients had received no hormone treatment prior to diagnosis of SCC. 19 patients presented dorsal or lumbar pain requiring opioid treatment on average 60 days before onset of neurological symptoms (range 10-840). All patients underwent steroid treatment; the 8 patients without prior hormone therapy were treated with bilateral orchidectomy, 1 out of these 8 patients had castration without other treatments; 12 patients underwent radiotherapy alone and 9 radiotherapy and laminectomy; 2 patients were in terminal conditions and receive only steroid treatment. Overall 15/24 patients were ambulant after treatment. 8 out of 9 patients treated by laminectomy and radiotherapy were ambulant after treatment versus 7 out of 12 patients treated by radiotherapy alone.17 patients died during follow-up with a median survival of 4 months (2 weeks to 49 months). 7 patients were alive at the last control with a mean follow-up of 10 months (range 4-40).

CONCLUSION

Outlook in patients with spinal cord compression from metastatic prostate cancer is poor. Efforts must be concentrated on prevention of spinal cord compression. Patients with hormone resistant prostate cancer who develop persistent back pain should undergo imaging studies (bone scan, spine CT-scan or MNR) and prophylactic local radiotherapy to the spine if bony metastases are identified.

Zoledronic acid: A new parenteral bisphosphonate

BACKGROUND

Inhibition of bone resorption using bisphosphonates is an important step in palliation of complications of advanced cancer, such as hypercalcemia and metastatic bone disease.

OBJECTIVE

The goal of this article was to describe the pharmacologic properties of zoledronic acid (zoledronate) and discuss findings from preclinical and clinical studies of its use in skeletal disorders.

METHODS

Relevant English-language literature was identified using the terms zoledronic acid, zoledronate, Zometa, and 118072-93-8 through searches of MEDLINE (1966-June 2003) and International Pharmaceutical Abstracts (1970-June 2003), and abstract proceedings from the American Society of Clinical Oncology (1997-2002).

RESULTS

Zoledronic acid is a nitrogen-containing bisphosphonate that inhibits bone resorption. It is indicated for the treatment of hypercalcemia of malignancy and for the treatment of patients with multiple myeloma or documented metastasis from solid tumors, in conjunction with standard antineoplastic therapy. The recommended dosage is 4 mg via IV over >or= 15 minutes every 3 or 4 weeks. Compared with pamidronate 90 mg, zoledronic acid 4 and 8 mg provided a higher complete response rate for hypercalcemia of malignancy by day 10 (88.4% and 86.7% vs 69.7%; P = 0.002 and P = 0.015) and longer duration of action (median time to relapse, 30 and 40 days vs 17 days; P = 0.001 and P = 0.007). In patients with breast cancer or multiple myeloma, zoledronic acid was as effective as pamidronate in delaying time to a first skeletal-related event (373 days vs 363 days). In patients with hormone-refractory prostate cancer and bone metastases, zoledronic acid 4 mg reduced the proportion of patients who experienced a skeletal-related event (33% vs 44% with placebo; P = 0.021) or a skeletal fracture (13% vs 22% with placebo; P = 0.015). In patients with bone metastases from solid tumors, zoledronic acid delayed the median time to a first skeletal-related event (230 days vs 163 days with placebo; P = 0.023). Common adverse events include fever, nausea, constipation, fatigue, and bone pain.

CONCLUSION

Zoledronic acid is an effective and generally well-tolerated treatment for hypercalcemia of malignancy and skeletal complications of metastatic bone disease.

Fever After Zoledronic Acid Administration Is Due to Increase in TNF-αand IL-6

The most common adverse event typically associated with bisphosphonate therapy is transient fever. The aim of this study was to define the role of the main cytokines of the acute-phase reaction interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) involved in the pathogenesis of zoledronic acid-induced fever. Eighteen consecutive cancer patients with bone metastases were treated, for the first time, with a single dose of 4 mg zoledronic acid infusion. They were prospectively evaluated for circulating TNF-alpha, interferon-gamma (IFN-gamma), and IL-6 levels at different times, just before and 1, 2, 7, and 21 days after diphosphonate infusion. Clinical and standard laboratory parameters were recorded at the same time points. TNF-alpha circulating levels increased significantly 1 and 2 days after zoledronic acid infusion (respectively, p = 0.002 and p < 0.001) and then decreased to levels similar to the basal levels. IL-6 levels increased significantly 1 day after the infusion (p = 0.007), returning to values similar to the median basal values 2 days after zoledronic acid administration. Moreover, in patients who experienced fever, the TNF-alpha and IL-6 increases were higher than in patients without fever. No statistically significant differences in IFN-gamma were identified at different time points in patients with and without fever. Our results show that zoledronic acid induces transient TNF-alpha and IL-6 increases and that these increases are higher in patients who have developed fever, suggesting that these cytokines could be responsible for fever pathogenesis. The sharp reduction in serum calcium levels observed in patients with fever may be related to zoledronic acid pharmacokinetic modifications.

Long-term efficacy and safety of zoledronic acid compared with pamidronate disodium in the treatment of skeletal complications in patients with advanced multiple myeloma or breast carcinoma

BACKGROUND

The goal of the current study was to compare the long-term (25-month) safety and efficacy of zoledronic acid with pamidronate in patients with bone lesions secondary to advanced breast carcinoma or multiple myeloma.

METHODS

Patients (n = 1648) were randomized to receive 4 mg or 8 mg (reduced to 4 mg) zoledronic acid as a 15-minute infusion or to receive 90 mg pamidronate as a 2-hour infusion every 3-4 weeks for 24 months. The primary endpoint was the proportion of patients with at least 1 skeletal-related event (SRE), defined as pathologic fracture, spinal cord compression, radiation therapy, or surgery to bone. Secondary analyses included time to first SRE, skeletal morbidity rate, and multiple-event analysis. Hypercalcemia of malignancy (HCM) was included as an SRE in some secondary analyses.

RESULTS

After 25 months of follow-up, zoledronic acid reduced the overall proportion of patients with an SRE and reduced the skeletal morbidity rate similar to pamidronate. Compared with pamidronate, zoledronic acid (4 mg) reduced the overall risk of developing skeletal complications (including HCM) by an additional 16% (P = 0.030). In patients with breast carcinoma, zoledronic acid (4 mg) was significantly more effective than pamidronate, reducing the risk of SREs by an additional 20% (P = 0.025) compared with pamidronate and by an additional 30% in patients receiving hormonal therapy (P = 0.009). Zoledronic acid (4 mg) and pamidronate were tolerated equally well. The most common adverse events included bone pain, nausea, and fatigue.

CONCLUSIONS

Long-term follow-up data confirm that zoledronic acid was more effective than pamidronate in reducing the risk of skeletal complications in patients with bone metastases from breast carcinoma and was of similar efficacy in patients with multiple myeloma.

The antineoplastic role of bisphosphonates: from basic research to clinical evidence

Bisphosphonates are now well established as successful agents for the prevention and treatment of postmenopausal osteoporosis, corticosteroid-induced bone loss and Paget's disease. Bisphosphonates have also recently become important in the management of cancer-induced bone disease, and they now have a widely recognized role for patients with multiple myeloma and bone metastases secondary to breast cancer and prostate cancer. Recent studies suggest that, besides the strong antiosteoclastic activity, the efficacy of such compounds in the oncological setting could also be due also to direct antitumor effect, exerted at different levels. Here, after a brief analysis of the chemical structure, we will review the antineoplastic and biological properties of bisphosphonates. We will start from well estabilished mechanisms of action and go on to discuss the latest evidence and hypotheses. In particular, we will review the antiresorptive properties in malignant osteolysis and the recent evidence of a direct antitumor effect. Furthermore, this review will analyze the influence of bisphosphonates on cancer growth factor release, their effect on cancer cell adhesion, invasion and viability, the proapoptotic potential on cancer cells, the antiangiogenic effect, and, finally, the immunomodulating properties of bisphosphonates on the gammadelta T cell population.

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.

The renal effects of minimally nephrotoxic doses of ibandronate and zoledronate following single and intermittent intravenous administration in rats

Rapid, intravenous (i.v.) administration of high doses of bisphosphonates has been associated with acute renal toxicity. This controlled, preclinical study over 25 weeks investigated the potential for subclinical renal damage to accumulate to clinically relevant levels when minimally nephrotoxic doses of ibandronate (1 mg/kg) or zoledronate (1 or 3 mg/kg) were given intermittently, with a between-dose interval of 3 weeks, or as a single dose by i.v. injection. In rats, a single dose and intermittent dosing of ibandronate resulted in a similar incidence (one of six and two of six rats, respectively) and severity score (1.0 for both) of proximal tubular degeneration and single cell necrosis. No accumulation of histopathological renal damage occurred. However, intermittent dosing of zoledronate induced a higher incidence (six of six rats) and severity score (3.0) of renal damage compared with single dosing (four of six rats and 1.3, respectively). Accumulation of renal damage was also observed for a lower intermittent dose of zoledronate (1 mg/kg) that had not exhibited histopathological renal damage when given as a single 1 mg/kg dose. Biochemical parameters confirmed these histopathological findings. In summary, the results from this study indicate that administering ibandronate intermittently provides sufficient time for regeneration of potential subclinical renal damage.

Clinical approaches to osseous metastases in prostate cancer

BACKGROUND

Prostate cancer is unique among solid tumors in its proclivity to metastasize primarily to bone. Osseous metastases pose a formidable health threat to patients with metastatic disease, putting them at risk for pain, marrow crowding, fracture, and other sequelae. Treatments directed against bone disease have the potential both to palliate pain and to increase survival.

CONCLUSIONS

A number of agents exist that have the potential to palliate the effects of osseous metastases and should be routinely applied in the clinical care of the patient with advanced prostate cancer. These include hormones, bone-seeking radiopharmaceuticals, chemotherapy, and bisphosphonates. Strategies under investigation aim to eradicate bone disease, and not merely palliate symptoms. These approaches combine those listed above with tumor-directed targeting of osseous disease and manipulation of the biology that underlies the cancer's relationship to bone.

Randomized, double-blind, controlled trial of mitoxantrone/prednisone and clodronate versus mitoxantrone/prednisone and placebo in patients with hormone-refractory prostate cancer and pain

PURPOSE

To compare the incidence of palliative response in patients with hormone-resistant prostate cancer (HRPC) treated with mitoxantrone and prednisone (MP) plus clodronate with that of patients treated with MP plus placebo.

MATERIALS AND METHODS

Men with HRPC, bone metastases, and bone pain were randomly assigned to receive clodronate 1,500 mg administered intravenously (IV) or placebo every 3 weeks, in combination with mitoxantrone 12 mg/m2 IV every 3 weeks and prednisone 5 mg orally bid. Patients completed the present pain intensity (PPI) index and Prostate Cancer-Specific Quality-of-Life Instrument at each treatment visit and used a diary to record analgesic use on a daily basis. The primary end point was a reduction to zero or of two points in the PPI or a decrease of 50% in analgesic intake, without increase in either.

RESULTS

The study accrued 209 eligible patients over 44 months. One hundred sixty patients (77%) had mild PPI scores (1 or 2), and 49 (24%) had moderate PPI scores (3 or 4). The primary end point of palliative response was achieved in 46 (46%) of 104 patients on the clodronate arm and in 41 (39%) of 105 patients on the placebo arm (P =.54). The median duration of response, symptomatic disease progression-free survival, overall survival, and overall quality of life were similar between the arms. Subgroup analysis suggested possible benefit in patients with more severe pain.

CONCLUSION

MP provides useful palliation in symptomatic men with HRPC. Clodronate does not increase the rate of palliative response or overall quality of life. Clodronate may be beneficial to patients who have moderate pain, but this requires further confirmation.

The use of zoledronic acid in the management of metastatic bone disease and hypercalcaemia

Zoledronic acid is a potent, third generation, nitrogen-containing bisphosphonate, licensed for the management of skeletal metastases and hypercalcaemia of malignancy, both of which cause considerable morbidity. In the preclinical setting, zoledronic acid has demonstrated superior potency regarding inhibition of osteolysis and reduction of hypercalcaemia as compared with other bisphosphonates. Clinical trials have indicated that zoledronic acid is superior to pamidronate in suppressing osteolysis and in reducing hypercalcaemia of malignancy. Its main mechanism of action is induction of osteoclast apoptosis through inhibition of the mevalonate pathway. Zoledronic acid has also demonstrated direct anti-tumour activity both in vitro and in animal models, suggesting it may be of benefit in preventing the formation of bone metastases. Clinical trials are in progress, assessing the benefit of zoledronic acid in the adjuvant setting in both breast and prostate cancer.

Zoledronic acid versus placebo in the treatment of skeletal metastases in patients with lung cancer and other solid tumors: a phase III, double-blind, randomized trial--the Zoledronic Acid Lung Cancer and Other Solid Tumors Study Group

PURPOSE

To assess the efficacy and safety of zoledronic acid in patients with bone metastases secondary to solid tumors other than breast or prostate cancer.

PATIENTS AND METHODS

Patients were randomly assigned to receive zoledronic acid (4 or 8 mg) or placebo every 3 weeks for 9 months, with concomitant antineoplastic therapy. The 8-mg dose was reduced to 4 mg (8/4-mg group). The primary efficacy analysis was proportion of patients with at least one skeletal-related event (SRE), defined as pathologic fracture, spinal cord compression, radiation therapy to bone, and surgery to bone. Secondary analyses (time to first SRE, skeletal morbidity rate, and multiple event analysis) counted hypercalcemia as an SRE.

RESULTS

Among 773 patients with bone metastases from lung cancer or other solid tumors, the proportion with an SRE was reduced in both zoledronic acid groups compared with the placebo group (38% for 4 mg and 35% for 8/4 mg zoledronic acid v 44% for the placebo group; P =.127 and P =.023 for 4-mg and 8/4-mg groups, respectively). Additionally, 4 mg zoledronic acid significantly increased time to first event (median, 230 v 163 days for placebo; P =.023), an important end point in this poor-prognosis population, and significantly reduced the risk of developing skeletal events by multiple event analysis (hazard ratio = 0.732; P =.017). Zoledronic acid was well tolerated; the most common adverse events in all treatment groups included bone pain, nausea, anemia, and vomiting.

CONCLUSION

Zoledronic acid (4 mg infused over 15 minutes) is the first bisphosphonate to reduce skeletal complications in patients with bone metastases from solid tumors other than breast and prostate cancer.

Proven efficacy of zoledronic acid in the treatment of bone metastases in patients with breast cancer and other malignancies

Many advanced cancers, particularly breast cancer and prostate cancer, metastasize to the bone, resulting in painful lesions and skeletal complications. Intravenous bisphosphonate therapy is an important component of palliative care for patients with bone metastases, and pamidronate has been the standard of care for patients with breast cancer and multiple myeloma since 1996. However, zoledronic acid is the first bisphosphonate shown to significantly reduce skeletal morbidity in patients with a wide range of primary tumor types. Zoledronic acid has demonstrated efficacy in the management of hypercalcemia and metastatic bone disease. In phase III studies involving more than 3000 patients with multiple myeloma, breast cancer, prostate cancer, lung cancer, and other cancers, 4 mg zoledronic acid demonstrated consistent efficacy across a range of clinical end-points, and was safe and well tolerated when infused over 15 min. Based on these studies, zoledronic acid appears to be active in patients with bone metastases irrespective of tumor type, and should be considered as the standard of care for the treatment of bone metastases.

Injectable bisphosphonates in the treatment of postmenopausal osteoporosis

Osteoporosis is a "silent" disease and the patient has usually no clue of it until the occurrence of a fragility fracture. Prevention requires a continuous daily treatment that could be uncomfortable to the patient. Besides the recently introduced weekly oral schedules, injectable bisphosphonates have often been used as an off-label option to ameliorate compliance. In general, although with different efficiency, almost all injectable bisphosphonates can improve bone mineral density and suppress bone resorption markers. The effect of intravenous infusions of bisphosphonates are, to a large extent, similar to equivalent intramuscular administrations, but doses and dosing intervals represent the critical issues. Pain at the injection site and acute phase reactions are relatively common to intramuscular clodronate and intravenous infusions of nitrogen-containing bisphosphonates, respectively. Under certain circumstances, intermittent treatment with injectable bisphosphonates might represent a feasible alternative when compliance is at risk.

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.

Bisphosphonates and radiation therapy for palliation of metastatic bone disease

Radiotherapy is an established treatment for metastatic bone pain. It may be delivered as a localised low dose treatment for localised bone pain or systemically for more widespread symptoms using hemibody external beam radiotherapy or intravenous bone-seeking radioisotopes. Bisphosphonates have been shown to reduce morbidity from bone metastases when given to patients with asymptomatic disease from myeloma and primary breast and prostate cancers. They also reduce metastatic bone pain in these sites. In the absence of randomised data comparing radiotherapy with bisphosphonates in the same clinical setting, comparison of the response rates from individual trials of the two modalities suggests that the overall pain response in all tumour types from radiotherapy is around 80% compared to a similar rate in myeloma with bisphosphonates but only 40% in solid tumours. Optimal use of the two modalities requires further investigation but since they have different dose limiting toxicities their incorporation in a combined modality approach to metastatic bone pain is rational using the concepts of additive effect and spatial co-operation in which bisphosphonates provide background control alongside acute pain relief using radiotherapy. They are also an important alternative for bone pain where radiation tolerance has been reached or radiotherapy is not readily available.

Rationale for the use of bisphosphonates in osteoblastic and osteolytic bone lesions

Various primary malignancies develop bone metastases, and the resultant skeletal complications cause significant morbidity/mortality in advanced cancer patients. Bone lesions associated with metastases are traditionally classified radiologically as either osteolytic or osteoblastic, and both types of lesions are associated with elevated levels of specific bone resorption markers. Some common aspects in the pathophysiology of bone lesions have prompted speculation that treatments for osteolytic metastases might also be effective for predominantly osteoblastic metastases, such as in prostate cancer. Potent osteoclast activity inhibitors, bisphosphonates have been successful in the treatment of osteolytic tumor bone disease. Zoledronic acid is the first bisphosphonate shown to have a direct clinical benefit in the treatment of osteoblastic bone metastases, reducing the number and rate of skeletal events in prostate cancer patients with metastatic bone disease. Moreover, the shorter, more convenient infusion time and similar safety profile of 4 mg zoledronic acid compared with 90 mg pamidronate presently make zoledronic acid the preferred therapy for treatment of bone metastases in patients with all types of advanced malignancy.

Advances in supportive care of patients with cancer and bone metastases: nursing implications of zoledronic acid

The knowledge and training of nursing staff is essential for the safety and comfort of patients receiving i.v. therapies. The use of i.v. bisphosphonates as an adjunct to standard antineoplastic therapies in patients with advanced cancer is becoming widespread. Zoledronic acid and pamidronate (Zometa and Aredia, Novartis Pharmaceuticals Corporation, East Hanover, NJ) are nitrogen-containing bisphosphonates. Pamidronate has been the standard of care for patients with osteolytic bone lesions from breast cancer or multiple myeloma. However, zoledronic acid, which has demonstrated increased potency and a broad clinical utility, is emerging as the new standard of care. In addition to treating hypercalcemia of malignancy, zoledronic acid is approved for treating patients with bone metastases (osteolytic or osteoblastic) from a wide range of solid tumors, including breast, prostate, and lung cancers, or osteolytic bone lesions from multiple myeloma. Zoledronic acid (4 mg via a 15-minute infusion) has a safety profile comparable with pamidronate (90 mg via a two-hour infusion) and has demonstrated comparable or superior efficacy to that of pamidronate in every patient population tested. The shorter infusion time of zoledronic acid compared with that of pamidronate may provide added convenience, but safety guidelines should be followed for all i.v. bisphosphonate therapies. These guidelines and nursing care of patients receiving i.v. bisphosphonates are reviewed.

Bisphosphonates: expanded roles in the treatment of patients with cancer

Bisphosphonates are important inhibitors of osteoclastic bone resorption seen in patients with bone metastases associated with malignancy. Bisphosphonates are used in the treatment of patients with bone metastases and have been shown to reduce skeletal-related events and symptoms, contributing to improved patient outcomes and quality of life. These agents first were approved in the treatment of patients with osteoporosis and have been used for the past two decades in this role. Because bisphosphonates inhibit osteoclast-mediated bone resorption, the bone remodeling cycle slows down and an increase in bone mineral density occurs. These agents are useful in treatment for both hypercalcemia and pain, although they have not definitively shown improvement in survival time. Considerable interest exists in the use of bisphosphonates for prevention of bone metastases and their potential antitumor activity. These drugs are well tolerated and have minimal side effects, but they are not inexpensive. This article discusses the role of bisphosphonates in patients with cancer and future directions for further research.

The truth is out there: an overall perspective on androgen deprivation

Androgen deprivation therapy (ADT) is a mainstay in the treatment of prostate cancer. The ideal timing, duration and composition of ADT remains undefined. At the present time, first-line therapy consists of orchiectomy, LHRH agonists, or combined androgen blockade (CAB). However, new combinations and treatment settings show promise for improving outcomes and decreasing toxicity.

Maspin expression inhibits osteolysis, tumor growth, and angiogenesis in a model of prostate cancer bone metastasis

Emerging evidence indicates that tumor-associated proteolytic remodeling of bone matrix may underlie the capacity of tumor cells to colonize and survive in the bone microenvironment. Of particular importance, urokinase-type plasminogen activator (uPA) has been shown to correlate with human prostate cancer (PC) metastasis. The importance of this protease may be related to its ability to initiate a proteolytic cascade, leading to the activation of multiple proteases and growth factors. Previously, we showed that maspin, a serine protease inhibitor, specifically inhibits PC-associated uPA and PC cell invasion and motility in vitro. In this article, we showed that maspin-expressing transfectant cells derived from PC cell line DU145 were inhibited in in vitro extracellular matrix and collagen degradation assays. To test the effect of tumor-associated maspin on PC-induced bone matrix remodeling and tumor growth, we injected the maspin-transfected DU145 cells into human fetal bone fragments, which were previously implanted in immunodeficient mice. These studies showed that maspin expression decreased tumor growth, reduced osteolysis, and decreased angiogenesis. Furthermore, the maspin-expressing tumors contained significant fibrosis and collagen staining, and exhibited a more glandular organization. These data represent evidence that maspin inhibits PC-induced bone matrix remodeling and induces PC glandular redifferentiation. These results support our current working hypothesis that maspin exerts its tumor suppressive role, at least in part, by blocking the pericellular uPA system and suggest that maspin may offer an opportunity to improve therapeutic intervention of bone metastasis.

A Phase I/II study of strontium-89 combined with gemcitabine in the treatment of patients with androgen independent prostate carcinoma and bone metastases

BACKGROUND

The objectives of the current study were to determine the maximum tolerated dose and to evaluate the efficacy of gemcitabine given in combination with strontium-89 to patients with androgen independent prostate carcinoma.

METHODS

Patients with androgen-independent prostate carcinoma and painful osteoblastic bone metastases were eligible. On a 12-week course, patients received gemcitabine (600 mg/m(2) or 800 mg/m(2)) on Days 1, 8, 15, 43, 50, and 57. A single dose of strontium-89 (55 microCi/kg) was administered on Day 8.

RESULTS

Fifteen patients were registered, and all were assessable for response and toxicity. Four patients were treated at Dose Level 1 (gemcitabine 600 mg/m(2)) without dose-limiting toxicity. Eleven patients received a total of 13 courses at Dose Level 2 (gemcitabine 800 mg/m(2)). Platelet nadirs of 25000-50000 platelets per microL were common at Dose Level 2, and 1 patient had Grade 4 thrombocytopenia that was dose-limiting. Granulocyte nadirs up to < 500 granulocytes per microL occurred in 4 patients at Dose Level 2 and were reversible. There were no responses, as measured by prostate specific antigen concentration, although 6 patients (40%) had stable disease.

CONCLUSIONS

The authors concluded that 800 mg/m(2) gemcitabine was the maximum tolerated dose for the combination. The study was terminated on the basis that an overall response rate > than 10% was unlikely. Further study at this dose level and schedule is not warranted. .

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.

Randomized controlled trial of zoledronic acid to prevent bone loss in men receiving androgen deprivation therapy for nonmetastatic prostate cancer

PURPOSE

A multicenter double-blind, randomized, placebo controlled clinical trial was performed to assess the effect of zoledronic acid, a potent new bisphosphonate, on bone mineral density during androgen deprivation therapy for nonmetastatic prostate cancer.

MATERIALS AND METHODS

Men with M0 (no distant metastases) prostate cancer beginning androgen deprivation therapy were randomly assigned to receive 4 mg. zoledronic acid or placebo intravenously every 3 months for 1 year. The primary efficacy variable was the percent change from baseline to 1 year in bone mineral density of the lumbar spine as measured by dual energy x-ray absorptiometry.

RESULTS

A total of 106 men were enrolled in the trial. Mean bone mineral density in the lumbar spine increased by 5.6% in men receiving zoledronic acid and decreased by 2.2% in those given placebo (mean difference 7.8%, 95% confidence interval 5.6%-10.0%, p <0.001). Mean bone mineral density of the femoral neck, trochanter and total hip also increased in the zoledronic acid group and decreased in the placebo group. Zoledronic acid was well tolerated.

CONCLUSIONS

Zoledronic acid increases bone mineral density in the hip and spine during androgen deprivation therapy for nonmetastatic prostate cancer.

An evidence-based approach to prostate cancer follow-up

The follow-up required for patients with prostate cancer is critically dependent upon the stage of disease and the ultimate goal for treatment. A major difficulty in follow-up in prostate cancer is the lack of data on outcome of various treatment modalities. Additionally, there is a lack of data on the use of treatment modalities early in the course of prostate cancer. Despite these limitations, there is a need to develop an approach to follow these patients pending further study. In this review, we critically assess the natural course of untreated prostate cancer, the complications of local therapy, and the controversy over early versus delayed hormonal therapy. As a result of this discussion, common themes emerge. Most patients diagnosed with prostate cancer die of causes other than prostate cancer such as cardiovascular disease and therefore require additional follow-up. Since patients experience local problems such as urinary obstruction more commonly than symptomatic metastatic disease, instruments to assess urinary symptoms are discussed. Finally, follow-up as a means to determine eligibility for clinical studies is discussed.

Pharmacotherapy of hormone refractory prostate cancer: new developments and challenges

Hormone refractory prostate cancer (HRPC) remains a challenge in the management of prostate cancer patients. With the widespread use of PSA (prostate specific antigen), recurrent disease after local treatment for localised prostate cancer is usually diagnosed long before evidence of metastatic disease. In many cases, hormonal manipulations are started at the time of biochemical relapse and therefore, patients become 'hormone refractory' earlier in the course of their disease, frequently with a good performance status, often with no evidence of metastatic disease, and they still face a considerably long life expectancy. Despite these changes, the need for more options in the treatment of HRPC is obvious. The pharmacological treatments that are in use and those that are under investigation for this group of patients will be discussed and include: cytotoxic agents including the microtubule inhibitors, alone and in combination with other conventional or experimental therapies such as calcitriol or thalidomide; treatment with epothilone analogues; endothelin receptor antagonists; palliative therapy with bisphosphonates, bone-targeted radiopharmaceuticals and other developing treatments such as vaccines, gene therapies and monoclonal antibodies.

Bone histology at autopsy and matched bone scintigraphy findings in patients with hormone refractory prostate cancer: the effect of bisphosphonate therapy on bone scintigraphy results

Bisphosphonates (BisP) are non-metabolized compounds with high bone affinity used in bone metastasis diagnosis and treatment. Currently, BisP are used to treat hypercalcemia of malignancy as well as to prevent, minimize, or delay skeletal morbidity. These compounds have a long half-life in bone. Thus long-term BisP treatment might saturate bone and interfere with a single-dose scanning agent used for bone scintigraphy when visualizing bone metastases. In an effort to answer this question, this study evaluated the concordance of histology and Technetium99 methylene diophosphonate (Tc99 MDP) bone scintigraphy in the diagnosis of bone metastases in prostate cancer patients. We assessed the concordance of findings between bone scintigraphy and histology using 188 bone biopsies from 11 autopsied patients who died with metastatic prostate cancer, 5 of whom were treated with pamidronate for 2 to 13 months before death. Overall agreement between histology and bone scintigraphy was 84%, 86% in non-pamidronate-treated patients and 82% in pamidronate-treated patients. Scintigraphic bone metastases without histological metastasis (false negatives = 12.7%) were observed in 24 anatomic locations; half of these were in one patient who had been treated with pamidronate and had no histological bone response to the carcinoma. There were only 4 sites where a positive bone scan was not associated with histologic metastasis (false positives = 2.21%). There was no statistical difference between the treated and non-treated group for concordance, specificity, sensitivity, positive and negative predictive values of bone scintigraphy and prevalence of histological abnormality. Long-term pamidronate treatment of prostate cancer bone metastases does not generally affect the ability to detect bone metastases with Tc99 MDP bone scintigraphy.

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.

Prostate cancer update

Research has yielded important insights into the impact of radical prostatectomy in patients with localized prostate cancer. Other recent research has focused on the role of nutrition in prostate cancer development and progression, improved prognostication for patients with both early and advanced prostate cancer, efficacy of adjuvant and neoadjuvant hormonal therapy, and development of novel agents. In addition, the role of bisphosphonates in patients with bone metastasis was established.

Zoledronic acid: a review of its use in the management of bone metastases and hypercalcaemia of malignancy

Zoledronic acid (Zometa) is an effective inhibitor of osteoclast-mediated bone resorption. Zoledronic acid demonstrated efficacy in the reduction of skeletalrelated events (SREs) in patients with multiple myeloma or bone metastases secondary to breast cancer, prostate cancer or other solid tumours, or hypercalcaemia of malignancy. Zoledronic acid was effective in patients with multiple myeloma or metastatic breast cancer with osteolytic or mixed bone lesions. The proportion of patients who experienced an SRE was similar during 12 months of treatment with zoledronic acid 4mg or pamidronic acid 90mg, but significantly fewer patients receiving zoledronic acid required radiotherapy to bone. Furthermore, in patients with breast cancer and osteolytic lesions, median time to a first SRE was more than 4 months longer with zoledronic acid than with pamidronic acid. In the multiple event analysis in a 12-month extension study (total study duration was 25 months) in patients with breast cancer, zoledronic acid was superior to pamidronic acid, with an 18% reduction in the risk of experiencing an SRE. Both drugs were associated with a slight reduction in pain. Zoledronic acid 4mg, compared with placebo, significantly reduced the proportion of patients with prostate cancer bone metastases experiencing an SRE, particularly pathological fractures after 15 months' treatment. The drug also significantly delayed the onset of skeletal complications compared with placebo in patients with prostate cancer and other solid tumours including non-small cell lung cancer. When administered as a single 15-minute intravenous infusion, zoledronic acid 4mg was significantly more effective than pamidronic acid administered as a 2-hour infusion in the treatment of severe hypercalcaemia of malignancy, as assessed by complete responses measuring normalised serum calcium concentrations at day 10 after a single dose. Furthermore, zoledronic acid normalised serum calcium concentrations significantly faster than pamidronic acid, and the duration of response and median time to relapse were approximately twice as long in zoledronic acid recipients than in pamidronic acid recipients. Zoledronic acid is well tolerated and has a similar tolerability profile to pamidronic acid. The most commonly reported adverse events included flu-like symptoms (fever, arthralgias, myalgias and bone pain), fatigue, gastrointestinal reactions, anaemia, weakness, dyspnoea and oedema.

CONCLUSION

In conjunction with antitumour therapy, zoledronic acid should be considered for routine use to reduce skeletal complications in patients with advanced malignancies involving bone. In patients with hypercalcaemia of malignancy, zoledronic acid is expected to become the treatment of choice.

Zoledronic acid (Zometa) use in bone disease

Zoledronic acid (Zometa) is the most recent addition to the clinically available bisphosphonates. Clinical benefits in metabolic, as well as cancer-related bone disease have been observed. In addition to its profound antiosteoclast effects, it has demonstrated anticancer effects in preclinical models. Zoledronic acid has been evaluated in randomized, double-blind clinical trials of osteoporosis, Paget's disease of bone, and metastatic, osteolytic and osteoblastic bone disease. Antiosteoclast activity has been demonstrated by reductions in the bone breakdown products N-telopeptide, C-telopeptide and deoxypyridinoline. Bone mineral density, measured by dual energy x-ray absorptometry, is increased with administration of zoledronic acid in postmenopausal osteoporosis. Clinical benefit in cancer includes improvement in bone pain, reductions in skeletal events and delay in time-to-first-skeletal-events. These zoledronic acid treatment benefits have been demonstrated in patients with multiple myeloma, breast, prostate and lung cancer, and other solid tumors.