Less pain does equal better quality of life following strontium-89 therapy for metastatic prostate cancer

Association of Urinary Strontium with Cardiovascular Disease Among the US Adults: A Cross-Sectional Analysis of the National Health and Nutrition Examination Survey

Previous studies have demonstrated the effects of environmental metals on the cardiovascular system. However, the relationship of strontium (Sr) to cardiovascular disease (CVD) in the general population has not been established. This cross-sectional study aimed to investigate the association between urinary Sr (U-Sr) and CVD in the US adults using data of 5255 participants from the National Health and Nutrition Examination Survey (NHANES) 2011-2016. Multivariable logistic regression and restricted cubic spline (RCS) regression were performed to assess the association between U-Sr and CVD. After multivariable adjustments, compared to the lowest quartile, the adjusted odds ratios (ORs) of CVD with 95% confidence intervals (CIs) across the quartiles were 0.65 (0.46, 0.92), 0.87 (0.61, 1.25), and 0.78 (0.55, 1.10). RCS plot revealed a nonlinear relationship between U-Sr levels and CVD (P for nonlinearity = 0.004). Threshold effect analysis identified the inflection point of U-Sr for the curve was 90.18 μg/g urinary creatinine (μg/g UCr). Each 1-unit increase in U-Sr was associated with a 1.1% decrease in CVD (OR 0.989; 95% CI 0.980-0.998) on the left side of the inflection point, but no significant association was observed on the right side of the inflection point. This study suggests a nonlinear association of U-Sr with CVD prevalence in the US general adults. These findings may have positive implications for the determination of appropriate Sr levels for public cardiovascular health. Given the cross-sectional study design, further prospective studies are warranted.

Prostate Cancer: Community Education and Disparities in Diagnosis and Treatment

Prostate cancer remains the leading diagnosed cancer and the second leading cause of death among American men. Despite improvements in screening modalities, diagnostics, and treatment, disparities exist among Black men in this country. The primary objective of this systematic review is to describe the reported disparities in screening, diagnostics, and treatments as well as efforts to alleviate these disparities through community and educational outreach efforts. Critical review took place of retrospective, prospective, and socially descriptive data of English language publications in the PubMed database. Despite more advanced presentation, lower rates of screening and diagnostic procedures, and low rates of trial inclusion, subanalyses have shown that various modalities of therapy are quite effective in Black populations. Moreover, patients treated on prospective clinical trials and within equal-access care environments have shown similar outcomes regardless of race. Additional prospective studies and enhanced participation in screening, diagnostic and genetic testing, clinical trials, and community-based educational endeavors are important to ensure equitable progress in prostate cancer for all patients. IMPLICATIONS FOR PRACTICE: Notable progress has been made with therapeutic advances for prostate cancer, but racial disparities continue to exist. Differing rates in screening and utility in diagnostic procedures play a role in these disparities. Black patients often present with more advanced disease, higher prostate-specific antigen, and other adverse factors, but outcomes can be attenuated in trials or in equal-access care environments. Recent data have shown that multiple modalities of therapy are quite effective in Black populations. Novel and bold hypotheses to increase inclusion in clinical trial, enhance decentralized trial efforts, and enact successful models of patient navigation and community partnership are vital to ensure continued progress in prostate cancer disparities.

Internal dosimetry studies of 170Tm-EDTMP complex, as a bone pain palliation agent, in human tissues based on animal data

Radiopharmaceuticals with therapeutic applications are designed to deliver high doses of radiation to target organs with minimizing unwanted radiation to healthy tissues. Owing to the potential of targeted radiotherapy to treat a wide range of malignancies, ¹⁷⁰Tm -EDTMP was developed for possible therapeutic applications. This study describes absorbed dose prediction of ¹⁷⁰Tm-EDTMP in human organs after animal injection which is determined via medical internal radiation dose (MIRD) and MCNP-4C code methods. It was estimated that a 1-MBq administration of ¹⁷⁰Tm-EDTMP into the human body would result in an absorbed dose of 37.9 mGy (MIRD method) and 38.02 mGy (MCNP-4C code) in the bone surface after 60 days post injection. Highest and lowest difference between MIRD and MCNP results are for lung and bone surface respectively. Finally, the results show that there is a good agreement between MIRD method and MCNP-4C simulation code for absorbed dose estimation.

Targeted Palliative Radionuclide Therapy for Metastatic Bone Pain

Bone metastasis develops in multiple malignancies with a wide range of incidence. The presence of multiple bone metastases, leading to a multitude of complications and poorer prognosis. The corresponding refractory bone pain is still a challenging issue managed through multidisciplinary approaches to enhance the quality of life. Radiopharmaceuticals are mainly used in the latest courses of the disease. Bone-pain palliation with easy-to-administer radionuclides offers advantages, including simultaneous treatment of multiple metastatic foci, the repeatability and also the combination with other therapies. Several β¯- and α-emitters as well as pharmaceuticals, from the very first [⁸⁹Sr]strontium-dichloride to recently introduced [²²³Ra]radium-dichloride, are investigated to identify an optimum agent. In addition, the combination of bone-seeking radiopharmaceuticals with chemotherapy or radiotherapy has been employed to enhance the outcome. Radiopharmaceuticals demonstrate an acceptable response rate in pain relief. Nevertheless, survival benefits have been documented in only a limited number of studies. In this review, we provide an overview of bone-seeking radiopharmaceuticals used for bone-pain palliation, their effectiveness and toxicity, as well as the results of the combination with other therapies. Bone-pain palliation with radiopharmaceuticals has been employed for eight decades. However, there are still new aspects yet to be established.

Spine and Non-spine Bone Metastases - Current Controversies and Future Direction

Bone is a common site of metastases in advanced cancers. The main symptom is pain, which increases morbidity and reduces quality of life. The treatment of bone metastases needs a multidisciplinary approach, with the main aim of relieving pain and improving quality of life. Apart from systemic anticancer therapy (hormonal therapy, chemotherapy or immunotherapy), there are several therapeutic options available to achieve palliation, including analgesics, surgery, local radiotherapy, bone-seeking radioisotopes and bone-modifying agents. Long-term use of non-steroidal analgesics and opiates is associated with significant side-effects, and tachyphylaxis. Radiotherapy is effective mainly in localised disease sites. Bone-targeting radionuclides are useful in patients with multiple metastatic lesions. Bone-modifying agents are beneficial in reducing skeletal-related events. This overview focuses on the role of surgery, including minimally invasive treatments, conventional radiotherapy in spinal and non-spinal bone metastases, bone-targeting radionuclides and bone-modifying agents in achieving palliation. We present the clinical data and their associated toxicity. Recent advances are also discussed.

Personalized Radiation Therapy in Cancer Pain Management

The majority of advanced cancer patients suffer from pain, which severely deteriorates their quality of life. Apart from analgesics, bisphosphonates, and invasive methods of analgesic treatment (e.g., intraspinal and epidural analgesics or neurolytic blockades), radiation therapy plays an important role in pain alleviation. It is delivered to a growing primary tumour, lymph nodes, or distant metastatic sites, producing pain of various intensity. Currently, different regiments of radiation therapy methods and techniques and various radiation dose fractionations are incorporated into the clinical practice. These include palliative radiation therapy, conventional external beam radiation therapy, as well as modern techniques of intensity modulated radiation therapy, volumetrically modulated arch therapy, stereotactic radiosurgery or stereotactic body radiation therapy, and brachytherapy or radionuclide treatment (e.g., radium-223, strontium-89 for multiple painful osseous metastases). The review describes the possibilities and effectiveness of individual patient-tailored conventional and innovative radiation therapy approaches aiming at pain relief in cancer patients.

Targeted Radionuclide Therapy of Painful Bone Metastases: Past Developments, Current Status, Recent Advances and Future Directions

Bone pain arising from secondary skeletal malignancy constitutes one of the most common types of chronic pain among patients with cancer which can lead to rapid deterioration of the quality of life. Radionuclide therapy using bone-seeking radiopharmaceuticals based on the concept of localization of the agent at bone metastases sites to deliver focal cytotoxic levels of radiation emerged as an effective treatment modality for the palliation of symptomatic bone metastases. Bone-seeking radiopharmaceuticals not only provide palliative benefit but also improve clinical outcomes in terms of overall and progression-free survival. There is a steadily expanding list of therapeutic radionuclides which are used or can potentially be used in either ionic form or in combination with carrier molecules for the management of bone metastases. This article offers a narrative review of the armamentarium of bone-targeting radiopharmaceuticals based on currently approved investigational and potentially useful radionuclides and examines their efficacy for the treatment of painful skeletal metastases. In addition, the article also highlights the processes, opportunities, and challenges involved in the development of bone-seeking radiopharmaceuticals. Radium-223 is the first agent in this class to show an overall survival advantage in Castration-Resistant Prostate Cancer (CRPC) patients with bone metastases. This review summarizes recent advances, current clinical practice using radiopharmaceuticals for bone pain palliation, and the expected future prospects in this field.

EANM guidelines for radionuclide therapy of bone metastases with beta-emitting radionuclides

The skeleton is the most common metastatic site in patients with advanced cancer. Pain is a major healthcare problem in patients with bone metastases. Bone-seeking radionuclides that selectively accumulate in the bone are used to treat cancer-induced bone pain and to prolong survival in selected groups of cancer patients. The goals of these guidelines are to assist nuclear medicine practitioners in: (a) evaluating patients who might be candidates for radionuclide treatment of bone metastases using beta-emitting radionuclides such as strontium-89 (89Sr), samarium-153 (153Sm) lexidronam (153Sm-EDTMP), and phosphorus-32 (32P) sodium phosphate; (b) performing the treatments; and

Clinical utility of 188Rhenium-hydroxyethylidene-1,1-diphosphonate as a bone pain palliative in multiple malignancies

¹⁸⁸Rhenium-hydroxyethylidene-1,1-diphosphonate (¹⁸⁸Re-HEDP) is a clinically established radiopharmaceutical for bone pain palliation of patients with metastatic bone cancer. Herein, the effectiveness of ¹⁸⁸Re-HEDP for the palliation of painful bone metastases was investigated in an uncontrolled initial trial in 48 patients with different types of advanced cancers. A group of 48 patients with painful bone metastases of lung, prostate, breast, renal, and bladder cancer was treated with 2.96–4.44 GBq of ¹⁸⁸Re-HEDP. The overall response rate in this group of patients was 89.5%, and their mean visual analog scale score showed a reduction from 9.1 to 5.3 (P < 0.003) after 1 week posttherapy. The patients did not report serious adverse effects either during intravenous administration or within 24 h postadministration of ¹⁸⁸Re-HEDP. Flare reaction was observed in 54.2% of patients between day 1 and day 3. There was no correlation between flare reaction and response to therapy (P < 0.05). Although bone marrow suppression was observed in patients receiving higher doses of ¹⁸⁸Re-HEDP, it did not result in any significant clinical problems. The present study confirmed the clinical utility and cost-effectiveness of ¹⁸⁸Re-HEDP for palliation of painful bone metastases from various types of cancer in developing countries.

Radiopharmaceuticals for the palliation of painful bone metastases

Metastatic bone pain is prevalent in advanced cancer, and, despite a plethora of available therapies, effective palliation remains a clinical challenge. Bone-seeking radiopharmaceuticals are an often-overlooked but valuable analgesic option for select patients. These agents work by binding to hydroxyapatite at the tumor-bone interface of osteoblastic lesions, delivering therapeutic doses of radiation to closely circumscribed tissue regions. They have been shown to reduce pain and improve quality of life. Their safety, simplicity, convenience of administration, and cost-effectiveness make them suitable for hospice and palliative care settings.

Comparative efficacy, tolerability, and survival outcomes of various radiopharmaceuticals in castration-resistant prostate cancer with bone metastasis: a meta-analysis of randomized controlled trials

Background

A meta-analysis was conducted to assess the impact of radiopharmaceuticals (RPs) in castration-resistant prostate cancer (CRPC) on pain control, symptomatic skeletal events (SSEs), toxicity profile, quality of life (QoL), and overall survival (OS).

Materials and methods

The PubMed/MEDLINE, CANCERLIT, EMBASE, Cochrane Library database, and other search engines were searched to identify randomized controlled trials (RCTs) comparing RPs with control (placebo or radiation therapy) in metastatic CRPC. Data were extracted and assessed for the risk of bias (Cochrane’s risk of bias tool). Pooled data were expressed as odds ratio (OR), with 95% confidence intervals (CIs; Mantel–Haenszel fixed-effects model).

Results

Eight RCTs with a total patient population of 1,877 patients were identified. The use of RP was associated with significant reduction in pain intensity and SSE (OR: 0.63, 95% CI: 0.51–0.78, I²=27%, P,0.0001), improved QoL (OR: 0.71, 95% CI: 0.55–0.91, I²=65%, three trials, 1,178 patients, P=0.006), and a minimal improved OS (OR: 0.84, 95% CI: 0.64–1.04, I²=47%, seven trials, 1,845 patients, P=0.11). A subgroup analysis suggested an improved OS with radium-223 (OR: 0.68, 95% CI: 0.51–0.90, one trial, 921 patients) and strontium-89 (OR: 0.21, 95% CI: 0.05–0.91, one trial, 49 patients). Strontium-89 (five trials) was associated with increased rates of grade 3 and 4 thrombocytopenia (OR: 4.26, 95% CI: 2.22–8.18, P=0.01), leucopenia (OR: 7.98, 95% CI: 1.82–34.95, P=0.02), pain flare (OR: 6.82, 95% CI: 3.42–13.55, P=0.04), and emesis (OR: 3.61, 95% CI: 1.76–7.40, P=0.02).

Conclusion

The use of RPs was associated with significant reduction in SSEs and improved QoL, while the radium-223-related OS benefit warrants further large, RCTs in docetaxel naive metastatic CRPC patients.

Assessment of anticancer-treatment outcome in patients with metastatic castration-resistant prostate cancer-going beyond PSA and imaging, a systematic literature review

BACKGROUND

In the past years, there has been significant progress in anticancer drug development for patients with metastatic castration-resistant prostate cancer (CRPC). However, the current instruments to assess clinical treatment response have limitations and may not sufficiently reflect patient benefit. Our objective was to systematically identify tools to evaluate both patient benefit and clinical anticancer-treatment response as basis for an international consensus process and development of a specific pragmatic instrument for men with CRPC.

METHODS

PubMed, Embase and CINAHL were searched to identify currently available tools to assess anticancer-treatment benefit, other than standard imaging procedures and prostate-specific antigen measurements, namely quality of life (QoL), detailed pain assessment, physical function and objective measures of other complex cancer-related syndromes in patients with CRPC. Additionally, all CRPC phase III trials published in the last 5 years were reviewed as well as studies using physical function tools in a general cancer population. The PRIMSA statement was followed for the systematic review process.

RESULTS

The search generated 1096 hits, 185 full-text papers were screened and finally 73 publications were included. Additional 89 publications were included by hand-search. We identified a total of 98 tools used in CRPC trials and grouped these into three categories: 22 tools assessing QoL domains and subgroups, 47 tools for pain assessment and 29 tools for objective measures, mainly physical function and assessment of skeletal disease burden.

CONCLUSION

A wide variety of assessment tools and also efforts to standardize and harmonize patient-reported outcomes and pain assessment were identified. However, the specific needs of the increasing CRPC population living longer with their incurable cancer are insufficiently captured and objective physical outcome measures are under-represented. In the age of new anticancer drug targets and principles, new methods to monitor patient relevant outcomes of antineoplastic therapy are of utmost importance.

The role of radiation therapy in the treatment of metastatic castrate-resistant prostate cancer

In the setting of castrate-resistant prostate cancer, patients present with a variety of symptoms, including bone metastases, spinal cord compression and advanced pelvic disease. Fortunately, a variety of radiotherapeutic options exist for palliation. This article focuses on these options, including both external beam radiotherapy and radiopharmaceuticals.

Palliative effects and adverse events of strontium-89 for prostate cancer patients with bone metastasis

The aim of the present study was to evaluate the palliative effects and adverse events of strontium-89 (Sr-89) in patients with bone metastasis from prostate cancer. A total of 18 patients with prostate cancer and painful bone metastases, as diagnosed on bone scintigraphy, who were treated with Sr-89 at the National Kyushu Cancer Center between February, 2008 and April, 2014 were reviewed. Of the 18 subjects, 13 (72.2%) achieved a pain response, whereas 5 were classified as pain non-responders (27.8%). According to a logistic regression analysis, the pre-administration characteristics, including age, prostate-specific antigen (PSA), alkaline phosphatase (ALP), history of bone-modifying agent administration, opioid use or palliative radiation therapy, time after the combined androgen blockade nadir and time since the pain onset, were not found to be significant predictors of the pain response. Similarly, the post-administration characteristics, including pain flares and the PSA and ALP response, were not found to be significant predictors of the pain response. Although no patients exhibited leukocyte toxicities, 2 patients experienced myelosuppression, involving anemia and thrombocytopenia, requiring transfusion of red cell or platelet concentrate following Sr-89 treatment. Of the 18 patients, 5 (27.8%) reported pain flares, all of whom were successfully treated with rescue drugs alone. According to the logistic regression analysis, of the pre-administration characteristics, only ALP was identified as a significant predictor of bone marrow suppression in the univariate and multivariate analyses (P=0.006). Therefore, Sr-89 treatment was found to be effective in ameliorating bone pain associated with metastasis from prostate cancer. Although it is difficult to identify the patients who will receive pain relief prior to Sr-89 administration, this drug should be administered during the early stages due to the potential for bone marrow suppression in patients with high ALP levels.

Tumor regression of multiple bone metastases from breast cancer after administration of strontium-89 chloride (Metastron)

We report a case of tumor regression of multiple bone metastases from breast carcinoma after administration of strontium-89 chloride. This case suggests that strontium-89 chloride can not only relieve bone metastases pain not responsive to analgesics, but may also have a tumoricidal effect on bone metastases.

Burden of skeletal-related events in prostate cancer: unmet need in pain improvement

PURPOSE

Up to 75% of patients with prostate cancer experience metastatic bone disease, which leads to an increased risk for skeletal-related events (SREs) including pathological bone fracture, spinal cord compression, and hypercalcemia of malignancy. Our objective was to systematically review the literature on the impact of SREs on quality of life (QOL), morbidity, and survival with a primary focus on the impact of SREs on pain in prostate cancer patients.

METHODS

We searched PubMed, limiting to peer-reviewed English-language human studies published in 2000-2010. The search was based on the US Food and Drug Administration and European Medicines Agency definition of an SRE, which includes pathologic fracture, spinal cord compression (SCC), hypercalcemia of malignancy, and radiotherapy or surgery to bone resulting from severe bone pain.

RESULTS

A total of 209 articles were screened, of which 173 were excluded, and 36 were included in this review. Patients with SREs had more pain and worse survival compared with no SREs. Pathologic bone fractures worsened QOL and were associated with shorter survival. Radiation therapy of SCC alleviated pain and improved morbidity. SCC was associated with decreases in patient survival. Radiation therapy and surgery to bone improved pain.

CONCLUSIONS

Specific SREs are associated with worse outcomes, including increased pain, poorer QOL, morbidity, and survival. Treatment of SREs is associated with improved pain, although there remains a need for more effective treatment of SREs in prostate cancer patients.

Efficacy outcomes by baseline prostate-specific antigen quartile in the AFFIRM trial

BACKGROUND

Enzalutamide significantly prolonged the survival of men with metastatic castration-resistant prostate cancer (PCa) after docetaxel in the randomised, phase 3, double-blind, placebo-controlled, multinational Patients with Progressive Castration-Resistant Prostate Cancer Previously Treated with Docetaxel-Based Chemotherapy (AFFIRM) trial (NCT00974311). Prostate-specific antigen (PSA) is commonly used as a marker of PCa disease burden, and the relationship of baseline PSA level to consequent treatment effect is of clinical interest.

OBJECTIVE

Exploratory analysis to evaluate any differences in patient characteristics and efficacy outcomes by baseline PSA level in the AFFIRM trial.

DESIGN, SETTING, AND PARTICIPANTS

Post hoc subanalysis of all randomised patients (n=1199) from the AFFIRM trial.

INTERVENTION

Participants were randomly assigned in a two-to-one ratio to receive oral enzalutamide 160 mg/d or placebo.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The major clinical efficacy end points were overall survival (OS), radiographic progression-free survival (rPFS), and time to PSA progression (TTPP) versus placebo; baseline characteristics, treatment duration, and subsequent antineoplastic therapy were compared by baseline PSA quartile.

RESULTS AND LIMITATIONS

Baseline PSA quartiles corresponded to the following PSA groups: <40 ng/ml (n=299), 40 to <111 ng/ml (n=300), 111 to <406 ng/ml (n=300), and ≥406 ng/ml (n=300). Enzalutamide consistently improved OS, rPFS, and TTPP compared with placebo across all subgroups, regardless of baseline PSA level. Hazard ratios for improvements in OS were 0.55 (95% confidence interval [CI], 0.36-0.85), 0.69 (95% CI, 0.47-1.02), 0.73 (95% CI, 0.53-1.01), and 0.53 (95% CI, 0.39-0.73) for PSA groups 1-4, respectively. The post hoc design of this analysis was not statistically powered to assess the relationship between baseline PSA and clinical efficacy outcomes.

CONCLUSIONS

This post hoc analysis of the AFFIRM trial demonstrates consistent benefits in OS, rPFS, and TTPP with enzalutamide regardless of baseline disease severity, as assessed by PSA.

PATIENT SUMMARY

Exploratory post hoc analysis of the AFFIRM trial showed that enzalutamide improves overall survival, radiographic progression-free survival, and time to prostate-specific antigen progression compared with placebo regardless of baseline disease severity, as assessed by prostate-specific antigen.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT00974311.

Strontium-89 (Sr-89) chloride in the treatment of various cancer patients with multiple bone metastases

BACKGROUND

Although the use of Sr-89 chloride in the treatment of patients with prostate and breast cancer has been widely reported, little information is available about its use for other malignancies. Here, we retrospectively analyzed the clinical profile of Sr-89 chloride in various patients with painful bone metastases.

METHODS

Entry criteria were a pathologically proven malignancy, clinically diagnosed multiple bone metastases, and adequate organ function. Sr-89 chloride (Metastron) was given by single intravenous infusion at 2 MBq/kg over 2 min. Self-reported outcome measures were used as a response index, including pain diary data on a 0-10 numeric rating scale (NRS).

RESULTS

Fifty-four consecutive patients with painful bone metastases were treated with Sr-89 chloride at the National Cancer Center Hospital East between March 2009 and July 2011, consisting of 26 with breast/prostate cancer and 28 with other malignancies (lung 8, head and neck 6, colorectal 6, others 8). Thirteen (24 %) patients experienced a transient increase in pain, which was categorized as a flare-up response. Grade 3-4 anemia was observed in 6 patients, 3 of whom required blood transfusion. Regarding efficacy, response rates and complete response rates were 71.2 % and 34.6 %, respectively, and time to response from the initiation of treatment was 36 days (range, 13-217). No significant difference in response rates was seen between patients with breast/prostate cancer and other cancers (breast/prostate 69.2 %, other 73.1 %; p = 0.76).

CONCLUSIONS

As in patients with breast and prostate cancer, Sr-89 chloride is a promising agent for the treatment of painful bone metastases in patients with various other malignancies.

Therapeutic strategies for bone metastases and their clinical sequelae in prostate cancer

OPINION STATEMENT

Skeletal metastases threaten quality of life, functionality, and longevity in patients with metastatic castration-resistant prostate cancer (mCRPC). Therapeutic strategies for bone metastases in prostate cancer can palliate pain, delay/prevent skeletal complications, and prolong survival. Pharmacologic agents representing several drug classes have demonstrated the ability to achieve these treatment goals in men with mCRPC. Skeletal-related events such as fracture and the need for radiation can be delayed using drugs that target the osteoclast/osteoblast pathway. Cancer-related bone pain can be palliated using beta-emitting bone-seeking radiopharmaceuticals such as samarium-153 EDTMP and strontium-89. Also, prospective randomized studies have demonstrated that cytotoxic chemotherapy can palliate bone pain. For the first time, bone-directed therapy has been shown to prolong survival using the novel alpha-emitting radiopharmaceutical radium-223. Given these multifold clinical benefits, treatments targeting bone metabolism, tumor-bone stromal interactions, and bone metastases themselves are now central elements of routine clinical care. Decisions about which agents, alone or in combination, will best serve the patient's and clinician's clinical goals is contingent on the treatment history to date, present disease manifestations, and symptomatology. Clinical trials exploring novel agents such as those targeting c-Met and Src are under way, using endpoints that directly address how patients feel, function, and survive.

Bone-targeting radiopharmaceuticals for the treatment of prostate cancer with bone metastases

Patients with castration-resistant prostate cancer (CRPC) frequently have metastases to the bone, which may cause pain and lead to a deterioration in quality-of-life. Bone-seeking radiopharmaceuticals are agents which, when administered systemically, localize to the site of bone metastases and deliver focal radiation there. In this review, we will summarize the current literature on bone-targeting radiopharmaceuticals for CRPC, focusing on strontium-89, samarium-153, rhenium-186 and radium-223. We will discuss their indications, clinical efficacy, and toxicities and highlight some of the challenges in optimizing treatment with these agents. Historically, clinical trials with these drugs have failed to demonstrate survival improvements, restricting their use for palliative purposes only. Radium-223 is the first agent in this class to show an overall survival advantage in CRPC patients with bone metastases. This landmark finding will likely have a considerable impact on the treatment paradigm of bone-metastatic CRPC, and will pave the way for further developments in the future.

The Role of Bone-Seeking Radionuclides in the Palliative Treatment of Patients with Painful Osteoblastic Skeletal Metastases

Background

Pain from skeletal metastases represents a major burden of advanced disease from solid tumors. Analgesic medications, bisphosphonates, hormonal agents, cytotoxic chemotherapy, and external beam radiotherapy are all effective treatments. However, patients often suffer from diffuse painful metastases and respond poorly to these standard therapies. Bone-seeking radionuclides can specifically target osteoblastic lesions to offer palliation of pain.

Methods

This article offers a narrative review of bone-seeking radionuclides, examines the evidence of safety and efficacy for the treatment of painful skeletal metastases, and presents guidelines for their appropriate use in this patient population.

Results

Seven bone-seeking radionuclides have shown evidence of both safety and efficacy in reducing pain from diffuse skeletal metastases. 153Sm-EDTMP and 89Sr are most commonly used in the United States and have been safely utilized for both repeat dosing as well as concurrent dosing with cytotoxic chemotherapy.

Conclusions

Targeted bone-seeking radionuclides are underutilized in the treatment of painful diffuse osteoblastic metastases. Several new agents are in active clinical investigation, and the pending approval of the first alpha-emitting radionuclide (223Ra) may offer a new class of agents that provide greater efficacy and less toxicity than those currently available for routine clinical use.

Systemic metabolic radiopharmaceutical therapy in the treatment of metastatic bone pain

Bone pain due to skeletal metastases constitutes the most common type of chronic pain among patients with cancer. It significantly decreases the patient's quality of life and is associated with comorbidities, such as hypercalcemia, pathologic fractures and spinal cord compression. Approximately 65% of patients with prostate or breast cancer and 35% of those with advanced lung, thyroid, and kidney cancers will have symptomatic skeletal metastases. The management of bone pain is extremely difficult and involves a multidisciplinary approach, which usually includes analgesics, hormone therapies, bisphosphonates, external beam radiation, and systemic radiopharmaceuticals. In patients with extensive osseous metastases, systemic radiopharmaceuticals should be the preferred adjunctive therapy for pain palliation. In this article, we review the current approved radiopharmaceutical armamentarium for bone pain palliation, focusing on indications, patient selection, efficacy, and different biochemical characteristics and toxicity of strontium-89 chloride, samarium-153 lexidronam, and rhenium-186 etidronate. A brief discussion on the available data on rhenium-188 is presented focusing on its major advantages and disadvantages. We also perform a concise appraisal of the other available treatment options, including pharmacologic and hormonal treatment modalities, external beam radiation, and bisphosphonates. Finally, the available data on combination therapy of radiopharmaceuticals with bisphosphonates or chemotherapy are discussed.

Leptomeningeal metastases from prostate cancer: an emerging clinical conundrum

Leptomeningeal metastases from solid tumors are relatively uncommon events with dismal prognosis. They can be seen mainly in patients with breast and lung cancer, and malignant melanoma, but have also been described in a variety of other tumor types. Leptomeningeal carcinomatosis from prostate cancer is an extremely rare complication, but as patients' survival is prolonged due to more effective treatments, it is expected that more patients will present with leptomeningeal involvement in advanced stages of the disease. In these cases high levels of prostate-specific antigen can be found in the cerebrospinal fluid. This comprehensive review presents the recent findings from the literature.

Serum Hemoglobin Levels Predict Response to Strontium-89 and Rhenium-186-HEDP Radionuclide Treatment for Painful Osseous Metastases in Prostate Cancer

OBJECTIVE

Retrospective comparative analysis of strontium-89 chloride (Sr89) and rhenium-186-hydroxyethylidene diphosphonate (Re186-HEDP) radionuclide treatment to find predictors of response in patients with painful metastases from hormone refractory prostate cancer.

PATIENTS AND METHODS

Clinical data from 60 hormone refractory PCA patients (i.e. rising PSA at castrate testosterone serum levels) was obtained. Twenty-nine were treated with Sr89, 31 were treated with Re186-HEDP for painful osseous metastasis. Response was defined as a patient-reported decrease in pain and/or reduction in pain medication with stable pain level. Hematological parameters and serum levels of PSA, alkaline phosphatase, and lactate dehydrogenase were assessed prior to and at 4-week intervals after treatment.

RESULTS

Median survival of all patients was 7 months (95% CI: 6-9 months). Overall, 33/60 (55%) patients reported a decrease in pain after the first radionuclide treatment. This percentage was similar for patients treated with Re168-HEDP and Sr89. Mean duration of reported pain response was 75 days (+/- 68 days) for Sr89 and 61 days (+/- 56 days) for Re186-HEDP, which was not significantly different. A lower blood hemoglobin concentration was associated with a lower pain response rate. In a multivariate Cox regression analysis, pain response to radionuclide treatment predicted longer survival after treatment.

CONCLUSIONS

Pain response was present in 55% of patients. Serum hemoglobin concentration prior to radionuclide treatment predicted pain response for both Re186-HEDP and Sr89. A reduction in pain upon radionuclide treatment was associated with a longer survival after treatment.

Cancer-related pain and quality of life in prostate cancer patients: assessment using the Functional Assessment of Prostate Cancer Therapy

The objective of this study was to assess disease-associated pain and quality of life (QOL) in patients with prostate cancer (PC). A total of 102 PC patients (clinical stage B, C: 20, D2: 82) patients were enrolled. QOL was assessed using the Functional Assessment of Cancer Therapy, General and Prostate (FACT-G/P). Disease-specific pain response was assessed using the visual analog scale and the face rating scale. In patients with stage D2 PC, mean age, serum prostate-specific antigen level, and performance status were 72.5 +/- 7.1 years (range, 55-88), 217 +/- 467 ng/mL (range, 0.1-2600), and 1.4 (0-4), respectively. The score of physical well-being and FACT-P was significantly lower in stage D2 patients, compared with those of stage B/C (P = 0.02, 0.0088, respectively). Performance status, extent of disease, and the visual analog scale were related with a poor QOL score (P = 0.0054, 0.01, <0.0001, respectively). Thirty-two patients (39%) had disease-specific pain, and 25 patients received a related treatment. Ten patients under morphine analgesics maintained better QOL in almost all domains, compared with the seven patients without any painkillers. Combined use of FACT and pain scales enhances the objective assessment of QOL and pain status in PC patients. Control of disease-associated pain is crucial to improving QOL in stage D2 PC patients.

EANM procedure guideline for treatment of refractory metastatic bone pain

INTRODUCTION

Bone pain is a common symptom of metastatic disease in cancer, experienced with various intensities by about 30% of cancer patients, during the development of their disease, up to 60-90% in the latest phases.

DISCUSSION

In addition to other therapies, such as analgesics, bisphosphonates, chemotherapy, hormonal therapy and external beam radiotherapy, bone-seeking radiopharmaceuticals are also used for the palliation of pain from bone metastases. Substantial advantages of bone palliation radionuclide therapy include the ability to simultaneously treat multiple sites of disease with a more probable therapeutic effect in earlier phases of metastatic disease, the ease of administration, the repeatability and the potential integration with the other treatments.

CONCLUSION

The Therapy, Oncology and Dosimetry Committees have worked together to revise the EANM guidelines on the use of bone-seeking radiopharmaceuticals. The purpose of this guideline is to assist the nuclear medicine physician in treating and managing patients undergoing such treatment.

Increased detections of leptomeningeal presentations in men with hormone refractory prostate cancer: an effect of improved systemic therapy?

Metastases from prostate cancer occur largely in bone through a haematogenous route. Metastatic spread of prostate cancer to the leptomeninges was rarely seen in the past. However, there has been a recent increase in presentations of leptomeningeal spread from prostate cancer in our institutions. Between 2004 and 2006, four patients were diagnosed with metastatic prostate cancer with leptomeningeal metastases in our centres. All four patients had hormone refractory prostate cancer and had previously had chemotherapy. The median survival of these patients was approximately 15 months from the time of hormone refractoriness. The prognosis of leptomeningeal metastasis secondary to metastatic prostate cancer is poor, ranging from 2 to 7 months as seen in our series. New cases of leptomeningeal metastases seen in our series are hypothesized to be secondary to the use of effective modern systemic treatments. A parallel might be drawn with the increased rate of central nervous system metastases in breast cancer since the introduction of effective cytotoxic treatments and more recently targeted therapies. We suggest the clinicians to be aware of the potential change of natural history and pattern of progression in metastatic prostate cancer.

Quality of life measurement in bone metastases: A literature review

Quality of life (QOL) has become an important consideration in the care of patients with bone metastases as prevalence, incidence and patient survival are on the rise. As a result, more interventional studies now measure patient’s QOL as a meaningful endpoint. However, well-developed bone metastases specific quality of life instruments are lacking. A literature review was conducted to better understand the nature of QOL instruments used in bone metastases trials. A total of 47 articles evaluating QOL in patients with bone metastases were identified. Twenty-five different instruments were used to evaluate QOL with study-designed questionnaires and the EORTC QLQ-C30 being most commonly employed. Many studies used more than one scale or instrument to measure QOL. This makes it difficult to compare QOL in bone metastases patients across studies and come to any formal conclusions. Therefore, this review demonstrates the need to develop a bone module that can be used across countries in future clinical trials.

The management of painful bone metastases with an emphasis on radionuclide therapy

OBJECTIVE

This review provides an update on the management of painful bone metastases, with an emphasis on radionuclide therapy, and introduces oligometastases and quantitative imaging evaluations for clinical trials.

METHODS

The current use of radionuclides, alone and in combination with chemotherapy and radiation therapy for painful bone metastases, is discussed, including toxicity, cost and overall outcomes.

RESULTS

Radionuclide therapy is shown to be a useful and cost-effective means of alleviating bone pain in metastatic disease and may be more effective when combined with chemotherapy, bisphosphonates and radiation therapy. Early use of radionuclides in pain therapy may limit cancer progression by inhibiting oligometastases development. Thus, radionuclides can significantly decrease patient morbidity, prolong patient survival, and may decrease the occurrence of new bone metastases.

CONCLUSION

Palliative pain therapy is critical for effectively managing bone metastases, with treatment options including analgesics, external beam radiotherapy, chemotherapy and radionuclides. Radionuclide therapy is underutilized. Recent studies using radionuclides with chemotherapy and bisphosponates, or using newer radionuclides or combinations of radionuclides and treatment paradigms (e.g., higher activities, repetitive or cyclic administration, chemo sensitization, chemo supplementation), are encouraging. A comprehensive, inter-disciplinary clinical approach is needed. Clinical collaborations will optimize radionuclide therapy for pain palliation and increase awareness of its benefits.

Palliative radiation therapy in oncology

Palliative radiation therapy is considered when the incurable cancer patient has symptoms specifically related to a malignancy that may be relieved by localized treatment of the primary tumor or metastatic lesions. Developing a treatment plan with radiation in the palliative setting may be more difficult than the curative setting, where there are clear guidelines for many situations. Radiation therapy has been used successfully in the management of a variety of pain syndromes. Radiation also has proven effective in the management of other tumor-related symptoms, including bleeding, neurologic compromise, dysphagia, and airway obstruction. Palliative radiation can be delivered using a variety of techniques: external beam radiation therapy, intraluminal brachytherapy (radioactive seed delivery), and systemic radionucleotides.

Vertebral tumors: surgical versus nonsurgical treatment

The treatment of spinal tumors represents a challenge to spine care professionals. Fortunately, the incidence of new cases of primary malignant bone tumors is lower compared with that of other tumors. In the United States approximately 2000 malignant bone tumors of 7000 new sarcomas are diagnosed each year. Of these, 4% to 20% (80-400 tumors) of bone tumors are spinal tumors. Metastatic tumors are the most frequent tumor of bone and the most frequent tumor of the spinal column regardless of the origin of the primary tumor. More than 90% of spinal tumors are metastatic. Thirty to seventy percent of patients who die from cancer have evidence of vertebral metastases visible on careful postmortem examination, with the potential that this number could reach 85% in patients with breast cancer. Less than 10% of patients with spinal tumors present with spinal instability requiring surgical treatment; this accounts for approximately 18,000 new cases yearly. We will focus on the most recent advances in nonsurgical and surgical treatment of vertebral tumors. In surgical treatment, the evaluation and selection of patients, indications and surgical strategies, open and minimally invasive techniques, outcomes and complications will be discussed.

LEVEL OF EVIDENCE

Level V (expert opinion). See the Guidelines for Authors for a complete description of the levels of evidence.

Recent Developments in Nuclear Medicine in the Management of Bone Metastases

OBJECTIVE

To review recent developments and to examine the role of nuclear medicine-based radionuclide therapy in the management of bone metastases.

METHODS

Recent developments in the use of radionuclides were broadly reviewed in the context of treatment paradigms, radionuclide toxicity, cost, and overall outcomes, and an impression of the use of radionuclides in metastatic bone disease was derived.

RESULTS

Through a number of studies, radionuclide therapy has been shown to be an efficacious and cost-effective means of alleviating bone pain in metastatic disease. Moreover, its early use in pain therapy may limit cancer progression by inhibiting oligometastases. Thus, radionuclides can significantly decrease patient morbidity, increase patient survival, and perhaps attenuate the aggressiveness of cancer. Nonetheless, in comparison with analgesics, external beam radiotherapy, or surgery, it still appears to have lower priority among medical oncologists.

CONCLUSION

Bone pain palliation is critical for cancer patients afflicted with bone metastases, but radionuclides remain underutilized in such treatments. The authors propose that physician education regarding radionuclide therapy be improved and additional investigations to evaluate newer radionuclides and treatment paradigms (eg, higher activities, repetitive or cyclic administration, chemosensitization, or chemosupplementation) be strongly encouraged. A comprehensive and an interdisciplinary clinical approach toward increasing the use of radionuclides in alleviating metastatic bone pain is proposed. Data from clinical collaborations will help optimize radiopharmaceutical therapy for pain palliation, increase its awareness among oncologists, and contribute effectively to patient palliation and quality-of-life improvements.

Prognostic model of event-free survival for patients with androgen-independent prostate carcinoma

BACKGROUND

The current study was conducted to develop a prognostic model of event-free survival (EFS) in men with androgen-independent prostate carcinoma (AIPC).

METHODS

Data from 160 patients diagnosed with AIPC between 1989-2002 were reviewed. No patient had received cytotoxic chemotherapy. A univariate Cox proportional hazards model identified significant predictors of EFS. Recursive partitioning analysis divided these significant variables into prognostic risk groups. The final prognostic model was tested with a Cox proportional hazards model.

RESULTS

The final prognostic risk model included the presence of metastatic disease at the time of androgen-independent disease progression (P = 0.040), time to prostate-specific antigen (PSA) recurrence (P = 0.043), and PSA doubling time (P < 0.01). Three highly independent risk groups were identified. The observed median EFSs were 6.1 months (95% confidence interval [95= CI], 3.4-8.8 months), 33.6 months (95= CI, 25.3-41.9 months), and 96.1 months (95= CI, 57.9-134.3 months) for the low-risk, intermediate-risk, and high-risk groups, respectively. Each risk group was found to be independently predictive of EFS (P < 0.01). Patients who died of prostate carcinoma experienced significantly more clinical events than those who died of other causes (P < 0.01).

CONCLUSIONS

The prognostic model in the current study stratified patients into three highly significant and independent risk groups for EFS. A detailed PSA history and knowledge of metastatic disease are sufficient to risk-stratify patients with AIPC. One very unique aspect of this model was that it was developed from a patient cohort that never received chemotherapy.

Teletherapy and radiopharmaceutical therapy of painful bone metastases

Bone pain from metastatic disease is most common in cancers of the breast, prostate, and lung. Despite the World Health organization algorithm for treating such pain, the outcomes are not often satisfactory. In 2005, there will be 3 radiopharmaceuticals available in the United States that can reduce or relieve bone pain caused by osteoblastic metastases with apparently equal efficacy. Phosphorus-32 as sodium phosphate, strontium-89 ( 89Sr) as the chloride, and samarium-153 lexidronam may all be given intravenously (and 32P also orally) in patients where bone scintigraphy demonstrates a metastatic lesion causing the patient's bone pain. Side effects are usually mild and include pancytopenia with leukocyte and platelet nadirs at approximately 50% of baseline, and a mild-to-moderate, but brief, increase in pain ("flare") in approximately 10% of patients. At least 1 of these radiotracers, 89Sr, has the availability to reduce the incidence of new bone metastases as well, but, given alone, none prolong life. In a few studies in which 89Sr has been combined with chemotherapy, prolongation of patient survival has been demonstrated. Many questions remain as to the optimization of use of this group of radiopharmaceuticals, including whether combinations of radiopharmaceuticals with each other, with bisphosphonates or with chemotherapy can improve the therapeutic outcomes even more.

Radioisotopes for the palliation of metastatic bone cancer: a systematic review

Strontium-89 and samarium-153 are radioisotopes that are approved in the USA and Europe for the palliation of pain from metastatic bone cancer, whereas rhenium-186 and rhenium-188 are investigational. Radioisotopes are effective in providing pain relief with response rates of between 40% and 95%. Pain relief starts 1-4 weeks after the initiation of treatment, continues for up to 18 months, and is associated with a reduction in analgesic use in many patients. Thrombocytopenia and neutropenia are the most common toxic effects, but they are generally mild and reversible. Repeat doses are effective in providing pain relief in many patients. The effectiveness of radioisotopes can be greater when they are combined with chemotherapeutic agents such as cisplatin. Some studies with 89Sr and 153Sm indicate a reduction of hot spots on bone scans in up to 70% of patients, and suggest a possible tumoricidal action. Further studies are needed to address the questions of which isotope to use, what dose and schedule to use, and which patients will respond.

Radiopharmaceuticals for the palliation of painful bone metastases—a systematic review

BACKGROUND AND PURPOSE

The purpose was to develop a systematic review that would address the following question: what is the role of radiopharmaceuticals in the palliation of metastatic bone pain in adults with uncomplicated, multifocal painful bone metastases whose pain is not controlled with conventional analgesic regimens? The outcomes of interest are pain response, analgesic consumption, overall survival, adverse effects and quality of life.

MATERIALS AND METHODS

A systematic review of the English published literature was undertaken to provide evidence relevant to the above outcomes.

RESULTS

Six randomized phase III trials, two randomized phase II trials and one randomized crossover trial of strontium-89 were reviewed. A randomized phase III trial comparing strontium-89 plus cisplatin with strontium-89 plus placebo reported a significantly higher proportion of patients experiencing pain relief for a significantly longer duration with strontium-89 plus cisplatin. A randomized phase III trial comparing adjuvant strontium-89 with placebo following radiotherapy reported a higher proportion of pain-free patients with strontium-89. Patients who received strontium-89 also experienced fewer new sites of bone pain. A second, but underpowered study failed to confirm these results. In one randomized trial of strontium-89 versus radiotherapy (hemibody or local), patients treated with strontium-89 developed fewer new sites of pain. In a second trial comparing strontium-89 versus local radiotherapy, median overall survival was improved with radiotherapy, while pain response and time-to-progression were similar in the two groups. One randomized phase III trial reported no difference in pain relief between strontium-89 and placebo. Three randomized phase III trials and two randomized phase II trials investigating samarium-153 were reviewed. In a randomized phase III trial of three different doses of samarium-153, the pain responses were similar for all three doses. In a randomized phase III trial of two different doses of samarium-153 versus placebo, the complete pain response rate was significantly higher with the higher dose of samarium-153 compared with placebo. In a randomized phase III trial comparing samarium-153 with placebo, significant differences favouring samarium-153 were reported for pain and opiate use. In addition, one randomized phase III trial, two randomized phase II trials, one randomized crossover trial and 13 phase II or phase I trials of rhenium, one phase I trial of tin-117 m and one phase II trial of phosphorus-32 were reviewed. The majority of patients treated in trials of radiopharmaceuticals where histology was specified had metastatic breast cancer (approximately 5-10% of patients reported), metastatic hormone-refractory prostate cancer (80-90% of patients reported) or metastatic lung cancer (5-10% of patients reported). Information on histologic subtype was not available for a significant proportion of patients treated on trials (30-40% of patients reported).

CONCLUSIONS

Use of single-agent radiopharmaceuticals (strontium-89 and samarium-153) should be considered as a possible option for the palliation of multiple sites of bone pain from metastatic cancer where pain control with conventional analgesic regimens is unsatisfactory and where activity on a bone scan of the painful lesions is demonstrated. Ongoing clinical research should seek to establish the benefit of newer radiopharmaceuticals and radiopharmaceuticals in combination with other systemic therapies.

Targeting osseous metastases: rationale and development of radio-immunotherapy for prostate cancer

For patients with metastatic prostate cancer, bone is the primary site of tumor localization and the major cause of disease-related morbidity and mortality. Hormonal therapy and chemotherapy alone cannot eradicate disease harbored in bone. The delivery of radiotherapy to the reservoir of disease is an approach previously only achievable using bone-seeking radiopharmaceuticals. Now, however, with the identification of tumor-specific targets, antibodies are being used to deliver radiotherapy to these sites. In this article, we review the rationale behind this approach, the targets being explored, the radiation sources available, and the antibodies currently under clinical development.

Cancer pain assessment in clinical trials. A review of the literature (1999-2002)

The aim of this review was to evaluate the methods of pain measurement in controlled clinical trials in oncology published between 1999 and 2002. An electronic literature search strategy was used according to established criteria applied to the Medline database and PubMed search engine. Articles were selected to include only studies that had chronic cancer pain as the primary or secondary objective of a controlled clinical trial. A specific evaluation scheme was used to examine how pain measurement methods were chosen and implemented in the study procedures. The search strategy identified 613 articles, and 68 were selected for evaluation. Most articles (69%) chose unidimensional pain measurement tools, such as visual analogue scales, numerical rating scales and verbal rating scales, whereas others used questionnaires. The implementation of the pain assessment method was problematic in many studies, especially as far as time frame of pain assessment (70%), administration modalities (46%), and use of non-validated measurement methods (10%). Design of study and data analysis were often unclear about the definition of pain outcome measure (40%), patient compliance with pain assessment (98%), and impact of missing data (56%). Statistical techniques were seldom appropriate to the type of data collected and often inadequate to describe the pain variable under study. It is clear from this review that most authors were aware of the need of valid pain measurement tools to be used in clinical trials. However, too often these tools were not appropriately used in the trial, or at least their use was not described with sufficient accuracy in the trial methods.

Pain flare following external beam radiotherapy and meaningful change in pain scores in the treatment of bone metastases

BACKGROUND AND PURPOSE

To examine the incidence of pain flare following external beam radiotherapy and to determine what constitutes a meaningful change in pain scores in the treatment of bone metastases.

PATIENTS AND METHODS

Patients with bone metastases treated with external beam radiotherapy were asked to score their pain on a scale of 0-10 before the treatment (baseline), daily during the treatment and for 10 days after completion of external beam radiation. Pain flare was defined as a two-point increase from baseline pain in the pain scale of 0-10 with no decrease in analgesic intake or a 25% increase in analgesic intake employing daily oral morphine equivalent with no decrease in pain score. To distinguish pain flare from progression of pain, we required the pain score and analgesic intake to return back to baseline levels after the increase/flare. They were also asked to indicate if their pain changed during that time compared to pre-treatment level. The change in pain score was compared with patient perception.

RESULTS

Eighty-eight patients were evaluated in this study. There were 49 male and 39 female patients with the median age of 70 years. Twelve of 88 patients (14%) had pain flare on day 1. The overall incidence of pain flare during the study period ranged from 2 to 16%. A total of 797 pain scorings were obtained. Patients perceived an improvement in pain when their self-reported pain score decreased by at least two points.

CONCLUSIONS

Our study confirms the occurrence of pain flare following the external beam radiotherapy in the treatment of bone metastases. Further studies are required to predict who are at risk for flare. Appropriate measures can be taken to alleviate the pain flare. The finding in the meaningful change in pain scores supports the investigator-defined partial response used in some clinical trials.

Palliation of bone pain in prostate cancer using chemotherapy and strontium-89. A randomized phase II study

Strontium-89 is an established alternative for the alleviation of bone pain in prostate cancer. There are few data evaluating the effect on pain of palliative chemotherapy. The aim of this randomized phase II study was to assess and compare the analgesic efficacy of strontium-89 and chemotherapy (FEM=5-FU, epirubicin, and mitomycin C) in 35 patients with disseminated, hormone-refractory prostate cancer suffering from persisting bone pain despite analgesic treatment. In order to minimize the risk for imbalances regarding the two patient groups, a double-blind randomization was performed. A significant reduction in pain intensity and pain frequency was registered in both patient groups (P < 0.01 in both groups after 3 weeks). Side effects were generally mild in the strontium-89 group and significantly more severe in the FEM group. The effect of FEM on pain is surprising as chemotherapy has generally only limited effect on tumor growth in bone metastases due to prostate cancer. A possible explanation is that FEM has an inhibitory activity on the inflammatory component of metastases.

The Correlation Between Palliation of Bone Pain by Intravenous Strontium-89 and External Beam Radiation to Linked Field in Patients With Osteoblastic Bone Metastases

We studied the correlation between the efficacy of local external beam radiotherapy and the efficacy of strontium-89 in the palliation of osteoblastic metastatic bone pain in 43 patients with cancer. All 43 had been treated with hormonal or chemotherapy according to the primary malignancies and analgetic pharmacotherapy as needed, 36 received local external beam radiotherapy as a palliative before strontium-89 injection, and all 43 were ultimately treated with strontium-89 as salvage therapy. Responses to the first strontium treatment, and to the first radiation treatment if given, were taken from patient files. Pain was evaluated by Karnofsky performance status, analgesic dosage, and duration of response to treatment translated into numeric scores on a pain duration scale and an integrated response scale. The efficacy of limited field external radiation in metastatic bone pain palliation was 80.6% versus 58.1% for strontium-89. Patients treated with both external radiation and strontium had a positive correlation of 0.4 with a probability of P = 0.0158 between the responses to the 2 treatments, indicating that response to external radiotherapy could be viewed as an indicator of strontium-89 efficacy in metastatic osteoblastic bone pain palliation in the same patient. No significant correlation was found between strontium efficacy and gender, location of metastases to weight-bearing bones, duration of hormonal therapy or chemotherapy, or type of primary neoplasm.

Targeting osseous metastases: rationale and development of radio-immunotherapy for prostate cancer

For patients with metastatic prostate cancer, bone is the primary site of tumor localization and the major cause of disease-related morbidity and mortality. Hormonal therapy and chemotherapy alone cannot eradicate disease harbored in bone. The delivery of radiotherapy to the reservoir of disease is an approach previously only achievable using bone-seeking radiopharmaceuticals. Now, however, with the identification of tumor-specific targets, antibodies are being used to deliver radiotherapy to these sites. In this article, we review the rationale behind this approach, the targets being explored, the radiation sources available, and the antibodies currently under clinical development.