Usefulness of strontium-89 for bone pain palliation in metastatic breast cancer patients

Targeted Radiopharmaceutical Therapy for Bone Metastases

Radiopharmaceutical approaches for targeting bone metastasis have traditionally focused on palliation of pain. Several agents have been clinically used over the last several decades and have proven value in pain palliation providing pain relief and improving quality of life. The role is well established across several malignancies, most commonly used in osteoblastic prostate cancer patients. These agents have primarily based on targeting and uptake in bone matrix and have mostly included beta emitting isotopes. The advent alpha emitter and FDA approval of 223Ra-dichloride has created a paradigm shift in clinical approach from application for pain palliation to treatment of bone metastasis. The approval of 223Ra-dichloride given the survival benefit in metastatic prostate cancer patients, led to predominant use of this alpha emitter in prostate cancer patients. With rapid development of radiopharmaceutical therapies and approval of other targeted agents such as 177Lu-PSMA the approach to treatment of bone metastasis has further evolved and combination treatments have increasingly been applied. Novel approaches are needed to improve and expand the use of such therapies for treatment of bone metastasis. Combination therapies with different targeting mechanisms, combining chemotherapies and cocktail of alpha and beta emitters need further exploration.

Palliative care in the treatment of women with breast cancer: A scoping review

OBJECTIVES

Recent studies on the quality of life in women with breast cancer show a high prevalence of signs and symptoms that should be the focus of palliative care (PC), leading us to question the current role they play in addressing breast cancer. Therefore, the objective of this review is to map the scope of available literature on the role of PC in the treatment of women with breast cancer.

METHODS

This is a methodologically guided scoping review by the Joanna Briggs Institute and adapted to the PRISMA Extension for Scoping Reviews (PRISMA-ScR) Checklist for report writing. Systematic searches were conducted in 8 databases, an electronic repository, and gray literature. The searches were conducted with the support of a librarian. The study selection was managed through the RAYYAN software in a blind and independent manner by 2 reviewers. The extracted data were analyzed using the qualitative thematic analysis technique and discussed through textual categories.

RESULTS

A total of 9,812 studies were identified, of which only 136 articles and 3 sources of gray literature are included in this review. In terms of general characteristics, the majority were published in the USA (35.7%), had a cross-sectional design (44.8%), and were abstracts presented at scientific events (19.6%). The majority of interventions focused on palliative radiotherapy (13.6%). Thematic analysis identified 14 themes and 12 subthemes.

SIGNIFICANCE OF RESULTS

Our findings offer a comprehensive view of the evidence on PC in the treatment of breast cancer. Although a methodological quality assessment was not conducted, these results could guide professionals interested in the topic to position themselves in the current context. Additionally, a quick synthesis of recommendations on different palliative therapies is provided, which should be critically observed. Finally, multiple knowledge gaps are highlighted, which could be used for the development of future studies in this field.

Pain associated with breast cancer: etiologies and therapies

Pain associated with breast cancer is a prevalent problem that negatively affects quality of life. Breast cancer pain is not limited to the disease course itself but is also induced by current therapeutic strategies. This, combined with the increasing number of patients living with breast cancer, make pain management for breast cancer patients an increasingly important area of research. This narrative review presents a summary of pain associated with breast cancer, including pain related to the cancer disease process itself and pain associated with current therapeutic modalities including radiation, chemotherapy, immunotherapy, and surgery. Current pain management techniques, their limitations, and novel analgesic strategies are also discussed.

Purification of 89Sr from FBTR irradiated Yttria target by extraction chromatography using HDEHP impregnated XAD-7 resin

89Sr is used in bone pain palliative care of cancer patients and the same is being produced presently via the 89Y(n, p)89Sr reaction by irradiating yttria target in Fast Breeder Test Reactor (FBTR). An efficient separation method was standardized for the removal of bulk yttrium target by extraction chromatography using di(2-ethylhexyl) phosphoric acid (HDEHP) impregnated on XAD-7 resin. In the present paper, the extraction behavior of Sr(II) and Y(III) was studied as a function of the concentration of nitric acid in the aqueous phase and concentration of HDEHP in the resin phase. The separation of Sr(II) and Y(III) was standardized using the above resins and the method was subsequently applied satisfactorily for the removal of yttrium from the dissolver solution of FBTR irradiated yttria pellet towards the purification of 89Sr. A baseline separation of 89Sr and Y was achieved. Leaching and breakthrough capacity studies were evaluated for the resins and it was established that the stability and capacity of the resins were satisfactory. The breakthrough capacity was found to be 12 mg Y(III) per gram of the HDHEP resin whereas the leaching studies established that the resins are stable for multiple cycle of operations.

Diagnosis and Treatment of Bone Metastases in Breast Cancer: Radiotherapy, Local Approach and Systemic Therapy in a Guide for Clinicians

The standard care for metastatic breast cancer (MBC) is systemic therapies with imbrication of focal treatment for symptoms. Recently, thanks to implementation of radiological and metabolic exams and development of new target therapies, oligometastatic and oligoprogressive settings are even more common-paving the way to a paradigm change of focal treatments role. In fact, according to immunophenotype, radiotherapy can be considered with radical intent in these settings of patients. The aim of this literature review is to analyze available clinical data on prognosis of bone metastases from breast cancer and benefits of available treatments for developing a practical guide for clinicians.

Bone metastases: a comprehensive review of the literature

The last report of the World Health Organization (WHO) stated that approximately four million people experience bone pain due to malignant diseases. Among them, metastatic bone pain is one of the most important sources of complaint. The estimated median survival in the presence of bone metastases ranks from 10 to 12 weeks. Bone represents a potential target of distant metastases for the majority of malignant tumours. However, the exact incidence of bone metastases is unknown. Bone metastases have an important socio-economic impact, and due to the enhancement of the overall survivorship, their incidence is increasing. Malignant neoplasms such as lung, thyroid, renal cancer, multiple myeloma, and melanoma often metastasize to the bone. Bone metastases commonly localize to the spinal column, pelvis, shoulder, and distal femur. The proper treatment for painful skeletal metastases is still unknown. Hence, the purpose of this review of the literature was to update current evidence concerning the aetiogenesis, biological behaviour, and treatment algorithms for painful skeletal metastases.

Biodistribution of strontium and barium in the developing and mature skeleton of rats

Bone acts as a reservoir for many trace elements. Understanding the extent and pattern of elemental accumulation in the skeleton is important from diagnostic, therapeutic, and toxicological perspectives. Some elements are simply adsorbed to bone surfaces by electric force and are buried under bone mineral, while others can replace calcium atoms in the hydroxyapatite structure. In this article, we investigated the extent and pattern of skeletal uptake of barium and strontium in two different age groups, growing, and skeletally mature, in healthy rats. Animals were dosed orally for 4 weeks with either strontium chloride or barium chloride or combined. The distribution of trace elements was imaged in 3D using synchrotron K-edge subtraction micro-CT at 13.5 µm resolution and 2D electron probe microanalysis (EPMA). Bulk concentration of the elements in serum and bone (tibiae) was also measured by mass spectrometry to study the extent of uptake. Toxicological evaluation did not show any cardiotoxicity or nephrotoxicity. Both elements were primarily deposited in the areas of active bone turnover such as growth plates and trabecular bone. Barium and strontium concentration in the bones of juvenile rats was 2.3 times higher, while serum levels were 1.4 and 1.5 times lower than adults. In all treatment and age groups, strontium was preferred to barium even though equal molar concentrations were dosed. This study displayed spatial co-localization of barium and strontium in bone for the first time. Barium and strontium can be used as surrogates for calcium to study the pathological changes in animal models of bone disease and to study the effects of pharmaceutical compounds on bone micro-architecture and bone remodeling in high spatial sensitivity and precision.

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

3-D localization of non-radioactive strontium in osteoarthritic bone: Role in the dynamic labeling of bone pathological changes

The study objective was to visualize regions of bone that undergo pathological mineralization and/or remodeling during pathogenesis of osteoarthritis, by employing non-radioactive strontium as a dynamic tracer of bone turnover. Post traumatic osteoarthritis was surgically induced in skeletally mature rats, followed by in vivo micro-CT imaging for 12 weeks to assess bone micro-structural changes. Rats either received strontium ranelate daily for the entire course of study or only last 10 days before euthanization. Distribution of strontium in bone was assessed in two and three dimensions, using electron probe micro-analysis (EPMA) and synchrotron dual energy K-edge subtraction micro-CT (SRμCT), respectively. Considerable early formation of osteophytes around the collateral ligament attachments and margins of articulating surfaces were observed, followed by subchondral sclerosis at the later stages. Accordingly, strontium was heavily incorporated by mineralizing osteophytes at 4, 8, and 12 weeks post-surgery, whereas subchondral bone only incorporated strontium between weeks 8-12.This study showed low dose stable strontium can effectively serve as a dynamic tracer of bone turnover to study pathological bone micro-structural changes, at resolution higher than nuclear medicine. Co-administration of strontium during therapeutic drug intervention may show enormous utility in assessing the efficacy of those compounds upon adaptive bone physiology.

The elements of life and medicines

Which elements are essential for human life? Here we make an element-by-element journey through the periodic table and attempt to assess whether elements are essential or not, and if they are, whether there is a relevant code for them in the human genome. There are many difficulties such as the human biochemistry of several so-called essential elements is not well understood, and it is not clear how we should classify elements that are involved in the destruction of invading microorganisms, or elements which are essential for microorganisms with which we live in symbiosis. In general, genes do not code for the elements themselves, but for specific chemical species, i.e. for the element, its oxidation state, type and number of coordinated ligands, and the coordination geometry. Today, the biological periodic table is in a position somewhat similar to Mendeleev's chemical periodic table of 1869: there are gaps and we need to do more research to fill them. The periodic table also offers potential for novel therapeutic and diagnostic agents, based on not only essential elements, but also non-essential elements, and on radionuclides. Although the potential for inorganic chemistry in medicine was realized more than 2000 years ago, this area of research is still in its infancy. Future advances in the design of inorganic drugs require more knowledge of their mechanism of action, including target sites and metabolism. Temporal speciation of elements in their biological environments at the atomic level is a major challenge, for which new methods are urgently needed.

Medical treatment of breast cancer bone metastasis: from bisphosphonates to targeted drugs

Breast cancer bone metastasis causing severe morbidity is commonly encountered in daily clinical practice. It causes pain, pathologic fractures, spinal cord and other nerve compression syndromes and life threatening hypercalcemia. Breast cancer metastasizes to bone through complicated steps in which numerous molecules play roles. Metastatic cells disrupt normal bone turnover and create a vicious cycle to which treatment efforts should be directed. Bisphosphonates have been used safely for more than two decades. As a group they delay time to first skeletal related event and reduce pain, but do not prevent development of bone metastasis in patients with no bone metastasis, and also do not prolong survival. The receptor activator for nuclear factor κB ligand inhibitor denosumab delays time to first skeletal related event and reduces the skeletal morbidity rate. Radionuclides are another treatment option for bone pain. New targeted therapies and radionuclides are still under investigation. In this review we will focus on mechanisms of bone metastasis and its medical treatment in breast cancer patients.

Minimally invasive local treatments for bone and pulmonary metastases

Surgery and chemotherapy have historically been the mainstay of treatment in patients with metastatic disease. However there are many alternative therapies available to relieve the symptoms and morbidity of metastases. In this paper, we review the role and highlight the advantages of minimally invasive techniques employed in patients with pulmonary and bone metastases.

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.

Radionuclide Therapy of Bone Metastases

The skeleton is a potential metastatic target of many malignant tumors. Up to 85% of prostate and breast cancer patients may develop bone metastases causing severe pain syndromes in many of them. In patients suffering from multilocular, mainly osteoblastic lesions and pain syndrome, radionuclide therapy is recommended for pain palliation. Low-energy beta-emitting radionuclides ((153)samarium-ethylenediaminetetrameth-ylenephosphonate (EDTMP) and (89)strontium) deliver high radiation doses to bone metastases and micrometastases in the bone marrow, but only negligible doses to the hematopoietic marrow. The response rate regarding pain syndrome is about 75%; about 25% of the patients may even become pain free. The therapy is repeatable, depending on cell counts. Concomitant treatment with modern bisphosphonates does not interfere with the treatment effects. Clinical trials using a new, not yet approved nuclide ((223)Radium) and/or combinations of chemotherapy and radionuclides are aiming at a more curative approach.

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.

Comparison of strontium-89 solution sources in UK hospitals, 2003

Concerns have been raised within the nuclear medicine field about the accuracy of measurements of 89Sr. The 85Sr impurity present in the 89Sr solution has a significant effect on the response of radionuclide calibrators used in hospitals. A comparison was conducted between the National Physical Laboratory (NPL) and the UK hospital physics community. Only 58% of the results were within 5% of the NPL value. Work at NPL has resulted in correction factors for the NPL secondary standard radionuclide calibrator and for Capintec calibrators, which will produce a significant improvement in performance.

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.

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.

Role of strontium-89 as adjuvant to palliative external beam radiotherapy is questionable: results of a double-blind randomized study

PURPOSE

To explore the efficacy of adjuvant (89)Sr applied with external beam radiotherapy (EBRT) to treat bone metastases.

METHODS AND MATERIALS

Ninety-five patients were randomized to (89)Sr (Arm A) or saline (Arm B) on Day 1 of EBRT to demonstrate a reduction in 3-month physician-assessed subjective progression from 70% to 45%.

RESULTS

At 3 and 6 months, no difference between treatment arms was observed in the progression rate. At 3 months, the physician-assessed response rate for all patients was 25%, with 46% of the patients progressing. The pretreatment use of opiates was independently associated with short progression-free survival. On the basis of the quality-of-life assessments, pain relief occurred in 50% of patients and 32% experienced improvement in global quality of life, without impact from (89)Sr. Differences were observed between the physician evaluation of radiotherapy efficacy and the patient assessment. In Arm A, serum alkaline phosphatase, but not serum prostate-specific antigen, decreased during the first 3 months after treatment.

CONCLUSION

(89)Sr, adjuvant to ERBT, does not seem to reduce the number of patients with subjective progression at 3 months. Patients should be referred for palliative RT before their bone pain requires high doses of opiates. In radiotherapy trials, the evaluation of pain and pain relief remains problematic because of the confounding use of analgesics.

Strategies for improving quality of life in older patients with metastatic breast cancer

Given both the increase in the mean age of the population of Western countries and the high incidence of breast cancer beyond the age of 65 years, it is evident that breast cancer in older women will be a very common problem for the medical oncologist. Metastatic breast cancer is still not amenable to a cure; therefore quality of life during therapy is an important issue, which until recently has been poorly investigated. Similarly, despite recent advances in breast cancer therapy, physicians have been reluctant to enrol older patients in clinical trials, and there is a lack of data regarding this population. This review focuses on quality-of-life issues during metastatic breast cancer treatment in geriatric patients, comparing the standard therapeutic options and newer approaches. Although first-line endocrine therapy with tamoxifen remains a standard treatment, the newer third-generation aromatase inhibitors provide similar or better efficacy with fewer adverse effects and a better quality of life. It has been a common belief that chemotherapy impairs quality of life, but recent studies in advanced breast cancer have shown that this therapy has a positive effect on quality of life, at least in responders. Consequently, chemotherapy should not be denied to elderly patients with metastatic breast cancer, provided a prior geriatric assessment is performed to evaluate the risk-benefit ratio. New chemotherapy strategies, such as the taxanes and orally administered chemotherapy, represent a very attractive alternative for a better quality of life in elderly patients with metastatic breast cancer.