Strontium-89--precursor targeted therapy for pain relief of blastic metastatic disease

The unexplored role of alkali and alkaline earth elements (ALAEs) on the structure, processing, and biological effects of bioactive glasses

Bioactive glass has been employed in several medical applications since its inception in 1969. The compositions of these materials have been investigated extensively with emphasis on glass network formers, therapeutic transition metals, and glass network modifiers. Through these experiments, several commercial and experimental compositions have been developed with varying chemical durability, induced physiological responses, and hydroxyapatite forming abilities. In many of these studies, the concentrations of each alkali and alkaline earth element have been altered to monitor changes in structure and biological response. This review aims to discuss the impact of each alkali and alkaline earth element on the structure, processing, and biological effects of bioactive glass. We explore critical questions regarding these elements from both a glass science and biological perspective. Should elements with little biological impact be included? Are alkali free bioactive glasses more promising for greater biological responses? Does this mixed alkali effect show increased degradation rates and should it be employed for optimized dissolution? Each of these questions along with others are evaluated comprehensively and discussed in the final section where guidance for compositional design is provided.

Strontium-89 chloride delivery for painful bone metastases in patients with a history of prior irradiation

BACKGROUND

Re-irradiation of a previously irradiated site must be done with careful consideration to minimize dose to organs at risk.

AIMS

To evaluate pain response and safety of Sr-89 administration for painful bone metastases after prior irradiation.

METHODS

We retrospectively reviewed patients with Sr-89 injection for painful bone metastasis in a previously irradiated site. All patients were seen in follow-up at 1, 2, 3, and 4 months after injection and every 6 months thereafter. Pain control, toxicity, and pain progression-free survival were analyzed. Correlation of pain relapse with the following characteristics was analyzed: gender, age, primary tumor, tumor pathology, baseline performance status, and baseline verbal rating scale.

RESULTS

Among 25 patients analyzed (10 male, 15 female), median age was 68 (range, 50-81) years. Primary tumor sites included lung (n = 11), breast (n = 3), uterine cervix (n = 3), prostate (n = 3), and others (n = 5). Median follow-up was 25 (range, 1-76) months. Pain relief was observed in 24 patients (96.0%). One- and 2-year pain progression-free survival rates in these patients were 54.5% and 48.4%, respectively. Median time to pain progression was 5 (range, 2-16) months. Statistically significantly lower pain progression-free survival was observed in patients with osteolytic bone metastases (p < 0.01). No grade 3 or worse adverse events were observed.

CONCLUSION

Sr-89 injection showed pain relief in most of our patients with painful bone metastases in a previously irradiated site and caused no grade 3 or worse adverse events. Sr-89 is an option for patients with a painful bone metastasis in a previously irradiated site.

Added value of hybrid SPECT with CT imaging for predicting poor therapeutic efficacy of 89Sr in patients with bone metastasis

To utilize single-photon emission computed tomography/computed tomography (SPECT/CT) scanning to investigate the usefulness of nerve root compression (NRC) and radioactive cold zone lesions (RCZLs) for predicting poor therapeutic efficacy of strontium-89 chloride (Sr-89) in patients with bone metastasis. Patients with bone metastatic neoplasms who had undergone baseline bone SPECT/CT scanning before Sr-89 therapy (148 MBq Sr-89 chloride by an intravenous injection for each patient) between July 2011 and July 2018 were included. Bone SPECT/CT images were assessed by two readers independently. Associations between imaging features and therapeutic efficacy were obtained via multivariate logistic regression analysis. Of 231 patients analyzed, 50 (21.6%) had NRC at baseline. Of 31 patients who experienced poor therapeutic efficacy, 29 (93.5%) had NRC. In multivariate logistic regression analysis baseline NRC independently predicted poor therapeutic efficacy. The sensitivity of NRC for predicting poor therapeutic efficacy was 93.5%, specificity was 89.5%, positive predictive value was 58.0%, and negative predictive value was 98.9%. RCZLs were detected in17 patients (7.4%), of whom 14 experienced poor Sr-89 therapeutic efficacy. The sensitivity of the presence of RCZLs for predicting poor therapeutic efficacy was 45.2%, specificity was 98.5%, positive predictive value was 82.4%, and negative predictive value was 92.1%. After adjusting for age, bone metabolism and lesion type, the significant independent predictors of poor Sr-89 therapeutic efficacy were presence of NRC (p < 0.001) and RCZL (p = 0.001). NRC and RCZL on baseline bone SPECT/CT are reliable independent predictors of poor Sr-89 therapeutic efficacy in patients with bone metastasis. These associations may facilitate the administration of more effective therapeutic interventions.

Radioisotopes in management of metastatic prostate cancer

INTRODUCTION

Metastatic prostate cancer continues to be a leading cause of morbidity and mortality in men with prostate cancer. Over the last decade, the treatment landscape for patients with castrate-resistant disease has drastically changed, with several novel agents demonstrating an improvement in overall survival in large, multi-institutional randomized trials. Traditional treatment with radioisotopes has largely been in the palliative setting. However, the first in class radiopharmaceutical radium-223 has emerged as the only bone-directed treatment option demonstrating an improvement in overall survival.

METHODS

Medline publications from 1990 to 2016 were searched and reviewed to assess the use of currently approved radioisotopes in the management of prostate cancer including emerging data regarding integration with novel systemic therapies. New positron emission tomography-based radiotracers for advanced molecular imaging of prostate cancer were also queried.

RESULTS

Radioisotopes play a crucial role in the diagnosis and treatment of prostate cancer in the definitive and metastatic setting. Molecular imaging of prostate cancer and theranostics are currently being investigated in the clinical arena.

CONCLUSIONS

The use of modern radioisotopes in selected patients with mCRPC is associated with improvements in overall survival, pain control, and quality of life.

Metabolism and pharmacokinetics of radium-223 in prostate cancer

INTRODUCTION

Prostate cancer metastatic to bone is a cause of significant morbidity and mortality. Bone pain and other skeletal events negatively impact the quality of life in patients who might otherwise be functioning well. As such, there has been intense interest in the development of strategies and pharmaceuticals to address this problem.

AREAS COVERED

The authors reviewed the current literature for articles relevant to metastatic prostate cancer, clinical radiopharmaceuticals, castrate-resistant prostate cancer and development of Radium-223 . The authors have referenced primary literature, clinical trials and relevant review articles that summarize the history, development and current utilization of radiopharmaceuticals for management of bone metastases from prostate cancer.

EXPERT OPINION

Radium-223 is the first radiopharmaceutical with an overall survival benefit approved for the treatment of patients with castration-resistant prostate cancer, symptomatic bone metastasis and no known visceral metastatic disease. The additional benefit of clinically significant improved overall survival should lead to exploration of whether this agent can be used earlier in the treatment algorithm or combined with chemotherapy or androgen deprivation therapy. An individualized approach needs to be tailored to each patient based on their overall symptoms, disease burden, hematologic profile and goals of care.

Strontium-89 therapy for the treatment of huge osseous metastases in prostate carcinoma: A case report

Prostate cancer is a growing public health problem. The palliation of pain in patients with painful bone metastases is of primary importance in the clinical management of advanced cancer. Internal therapy with radionuclides, which concentrate at sites of increased bone turnover, is used to control pain and improve quality of life as an alternative to conventional therapies. In the present study, we report the case of a 52-year-old male who had been diagnosed with prostate cancer. The patient presented with severe pain in multiple areas, but particularly in the right hip. A whole-body bone scan revealed that the right hip, ilium and ischium were covered with huge metastatic lesions. Treatment with radionuclide strontium-89 chloride ((89)Sr) resulted in a partial response which was confirmed by the successful relief of pain and other imaging modalities. No significant change in the leukocyte or thrombocyte levels was observed. The results of the present study indicate that systemic radionuclide therapy using (89)Sr is an effective, well-tolerated and safe palliative treatment in patients with huge osseous metastases in prostate carcinoma.

Radiopharmaceuticals for bone metastasis therapy and beyond: a voyage from the past to the present and a look to the future

Bone cancer can be divided into primary and secondary (metastatic) bone cancer. Osteosarcoma is the most common type of primary bone cancer, but still is a rare cancer. The development of bone metastases is a common event for the cancer patient and the main cause of treatment failure and death, being chronic pain syndrome the most important complication. There are currently several therapeutic modalities for the treatment of metastatic bone disease, including radiation therapy. Treatment with radionuclides (β- and α-particle emitters and Auger electron cascades) is a safe and effective tool of medicine. There is a great deal of interest in diphosphonic acids in nuclear medicine as ligands for radiometals in bone-seeking diagnostic and therapeutic agents. Several radiopharmaceuticals have been designed with the phosphonates as ligands. A recent approach to develop an effective radiopharmaceutical for therapy of bone cancer was the design of a water-soluble polymer that would exploit the disrupted vasculature in tumors according to the enhanced permeability and retention effect. To enhance the effect of radionuclide therapy on the cancer cells, new strategies have recently been investigated, such as the combined radionuclide and chemotherapy, high-dose radionuclide therapy, and repeated radionuclide therapy.

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.

Effective use of strontium-89 in osseous metastases

Bone is one of the organs to which cancer metastasizes most frequently. However, it is not a vital organ, therefore, survival after the occurrence of osseous metastasis is relatively favorable. Improvements of medical treatment bring prolonged survival to patients with osseous metastases. But this makes us to recognize the importance of quality of life (QOL) due to several factors, including pain. It is important for oncologists to know how to deal with such painful osseous metastases, as pain relief may enable patients to live their remaining lives to the fullest. Strontium-89 (89Sr) has been used worldwide as in Japan, while being reported to have positive effects on pain relief and QOL improvement in patients with osseous metastases. This review paper is aimed to present not only the history, roles, and medical characters of 89Sr, but also new aspects, such as how to use bone turnover markers, which location of osseous metastases is suitable for effective use of 89Sr.

New approach for treatment of vertebral metastases using intensity-modulated radiotherapy

PURPOSE

To perform aggressive radiotherapy for vertebral metastases. Using very steep dose gradients from intensity-modulated radiotherapy (IMRT), a protocol based on the concept of partial volume dose to the spinal cord was evaluated.

PATIENTS AND METHODS

50 patients with vertebral metastases were treated using IMRT. In previously unirradiated cases, where a prescribed dose of 80 Gy (BED10) was delivered, the constraint to the spinal cord should be less than 100 Gy (BED2). For previously irradiated cases, on the other hand, the dose is the same as in the previously unirradiated case; however, constraints for the spinal cord are a cumulative BED2 of less than 150 Gy, BED2 of less than 100 Gy in each instance, and a treatment gap of more than 6 months. There were 6 patients considered for a partial volume dose to the spinal cord. They all received higher BED2, ranging from 51-157 Gy of D1cc.

RESULTS

Among the 24 patients who survived longer than 1 year, there was 1 case of transient radiation myelitis. There were no other cases of spinal cord sequelae.

CONCLUSION

Based on the present results, we recommend a BED2 of 100 Gy or less at D1cc as a constraint for the spinal cord in previously unirradiated cases, and a cumulative BED2 of 150 Gy or less at D1cc in previously irradiated cases, when the interval was not shorter than 6 months and the BED2 for each session was 100 Gy or less. The prescribed BED10 of 80 Gy could be safely delivered to the vertebral lesions.

NCCN Task Force Report: Bone Health in Cancer Care

Bone health and maintenance of bone integrity are important components of comprehensive cancer care in both early and late stages of disease. Risk factors for osteoporosis are increased in patients with cancer, including women with chemotherapy-induced ovarian failure, those treated with aromatase inhibitors for breast cancer, men receiving androgen-deprivation therapy for prostate cancer, and patients undergoing glucocorticoid therapy. The skeleton is a common site of metastatic cancer recurrence, and skeletal-related events are the cause of significant morbidity. The National Comprehensive Cancer Network (NCCN) convened a multidisciplinary task force on Bone Health in Cancer Care to discuss the progress made in identifying effective screening and therapeutic options for management of treatment-related bone loss; understanding the factors that result in bone metastases; managing skeletal metastases; and evolving strategies to reduce bone recurrences. This report summarizes presentations made at the meeting.

Repeated bone-targeted therapy for hormone-refractory prostate carcinoma: tandomized phase II trial with the new, high-energy radiopharmaceutical rhenium-188 hydroxyethylidenediphosphonate

PURPOSE

We investigated the effect of repeated bone-targeted therapy with rhenium-188 hydroxyethylidenediphosphonate (HEDP) in patients with progressive, hormone-resistant prostate carcinoma and bone pain. The aim of this study was to determine the pain palliation and the antitumor effect of rhenium-188 HEDP treatments.

PATIENTS AND METHODS

Sixty-four patients were randomly assigned to one of two groups for radionuclide therapy with rhenium-188 HEDP; patients of group A received a single injection, patients of group B received two injections (interval, 8 weeks). After therapy, patients were followed-up by assessment of pain palliation and clinical outcome until death.

RESULTS

In both groups, toxicity was low, with moderate thrombopenia and leukopenia (maximum common toxicity criteria grade of 2). The effectiveness of rhenium-188 HEDP for pain palliation was better in the repeated treatment group (group B), with a response rate and time of response of 92% and 5.66 months, respectively (P =.006 and P =.001). In group B, 11 (39%) of 28 patients had a prostate-specific antigen decrease of more than 50% for at least 8 weeks, compared with two (7%) of 30 patients in the single-injection group (group A). The median times to progression of group A and group B were 2.3 months (range, 0 to 12.2 months) and 7.0 months (range, 0 to 24.1 months), respectively (P =.0013), and the median overall survival times were 7.0 months (range, 1.3 to 36.7 months) and 12.7 months (range, 4.1 to 32.2 months), respectively (P =.043).

CONCLUSION

Compared with single-injection therapy, repeated bone-targeted therapy with rhenium-188 HEDP administered to patients with advanced progressive hormone-refractory prostate carcinoma enhanced pain palliation and improved progression-free and overall survival. Larger studies are justified to further evaluate the use of rhenium-188 HEDP.

Antalgic treatment of pain associated with bone metastases

Pain from metastases of primitive cancer is the first symptom of disease in 15--20% of patients and remains the most common cause of cancer-related pain. 30--70% of patients have metastases at diagnosis, and 80% of them at the moment of death. Functional impairment of skeleton, neurologic symptoms, pathological fractures and pain are the most important indications for palliative treatment which should result in tumor regression, relief in cancer-related symptoms and maintainance of functional integrity. Bone metastases are treated with the systemic therapies including radiotherapy, hormonal manipulation, biphosphonates, calcitonin, surgical treatment, and chemotherapy. Conventional use of opioids or non-steroidal anti-inflammatory drugs does not always produce satisfactory analgesic result in treated patients because of incidental and intermittent nature of pain and unacceptable side effects. Alternative strategies (peripheric and central nerve blocks, neurolysis) are frequently required. A proper use of different modalities of treatment enhances the probability of achieving relief of pain and maintaining an acceptable quality of life.

Local and systemic radiation for palliation of metastatic disease

Many radiotherapeutic treatment options are available for the palliation of patients with metastatic prostate cancer. These include local field radiotherapy to symptomatic sites of metastasis and the use of radioisotope therapy either alone or in combination with local field radiotherapy. To date, the majority of patients treated with radioisotope therapy have been treated with 89Sr. Other agents, such as 153Sm-EDTMP are available now, also. Combined radioisotope therapy, cytotoxic chemotherapy, and biphosphonates hold great promise.

A chelate theory for the mechanism of action of aspirin-like drugs

Two hundred years after the discovery of the pharmaceutical usefulness of aspirin, it and aspirin-like drugs, a family with an ever-increasing number of members, are an indispensable part of modern life. However, the question as to how these drugs work in the body has remained unsettled. It is postulated here that this group of drugs may exert their therapeutic (and adverse) effects by chelating various physiologically important metallic cations in the body. The chelate theory is supported by the vast majority, if not all, of the observations on these drugs made in the past.

Strontium-89 therapy and imaging with bremsstrahlung in bone metastases

The bone-seeking radiopharmaceutical Sr-89 has been used as a palliative treatment for patients with bone pain caused by bone metastases. The authors report the results of nine patients (three with prostate cancer, four with breast cancer, one with thyroid cancer, and one with lung cancer) who underwent therapy with Sr-89 chloride for painful bone metastases, and evaluate Sr-89 imaging with bremsstrahlung. Two levels of dosage (1.5 and 2.2 MBq/kg) were used. Sr-89 imaging was performed in seven patients 1 week after injection. Abnormal uptake was seen in all and was consistent with the results of Tc-99m HMDP imaging. Six patients were assessed at 3 months and three patients toward the time they were terminal; 78% (seven of nine) derived some benefit. Two patients had a favorable clinical response and showed improvement on Tc-99m HMDP imaging.

Serum PICP as a bone formation marker in 89Sr and external beam radiotherapy of prostatic bony metastases

The clinical management of skeletal metastatic disease is problematic because of the difficulty in treating and accurately monitoring therapy impact and disease progression. This investigation measured serum procollagen type I C-terminal peptide (PICP) concentrations as a semi-quantitative index of bone turnover in patients with metastatic prostatic adenocarcinoma before and following palliative 89Sr chloride therapy. 10 patients with early stage (stage A2, B1 and B2) biopsy-confirmed prostatic adenocarcinoma were investigated (n = 10). Two groups of 10 patients each (n = 10 per group) with advanced (stage D) metastatic prostatic adenocarcinoma who had previously undergone hormonal manipulation were also investigated. One group of patients with scintigraphically documented metastatic bone disease received additional irradiation for new symptomatic bone metastases, whereas the other group received 89Sr chloride therapy. A radioimmunoassay for PICP was used to measure serum concentrations of patients in each of these groups as well as positive and negative controls. The concentration of serum PICP rose from 649 +/- 279 before treatment with external beam radiotherapy to 927 +/- 157 ng ml-1 4 months after therapy (p < 0.05). However, the results demonstrated a four-fold decrease (p < 0.001) in serum PICP in clinical responders to 89Sr chloride therapy versus baseline 4 months after the completion of treatment. The clinical non-responders demonstrated no significant change in PICP concentrations during that interval. This may be due to an increase in untreated bony metastases in the non-89Sr treated group. Although a relatively small representative group of patients was studied, these data demonstrate that serum PICP concentration correlates with clinical response to 89Sr chloride therapy. This objective laboratory technique may be useful for monitoring and predicting the need for 89Sr chloride therapy and optimizing palliative care. It may also be extremely useful in predicting a therapeutic response to such intervention.

Postoperative irradiation treatment and bioresorbable implants in orthopaedic surgery: an experimental in vitro study

The influence of applied radiation on the degradation of a polyglycolide (PGA) test specimen was studied in vitro. There was no significant difference in the time-dependent degradation behaviour between the irradiated test specimen and controls. Mandatory irradiation of an operation site following surgery therefore does not contradict the employment of bioresorbable implants in orthopaedic surgery.

Strontium-89 for symptomatic metastatic prostate cancer to bone: recommendations for hospice patients

In our institution, 4 mCi doses of the radiopharmaceutical strontium-89 (Sr89) have been given to 101 prostate cancer patients suffering from symptomatic bone metastases. Patients were prospectively analyzed for pain response, treatment-related hematologic toxicity, and survival. Pre-treatment clinical factors were correlated with outcome. Karnofsky Performance Scores (KPS) predicted for survival and pain response. Myelosuppression from the Sr89 treatment was minimal. Twenty-eight of the treated patients had a KPS of 60 or less. This group of patients had a median actuarial survival of 17.5 weeks, and collectively, met Hospice admission survival criteria. In a subset analysis of this group, patients with a KPS of 50 or less demonstrated a low pain response (40%) and average survival (12.5 weeks), both of which did not appear to justify the significant cost and risk of toxicity associated with Sr89 treatment. In these patients, opioids appeared to offer more cost-effective pain control. Patients with a pre-treatment KPS score of 60 had a mean survival of 20.5 weeks following Sr89 therapy, with 42 percent of patients experiencing a reduction in pain. We conclude that patients with a pretreatment KPS of 50 or less should not be treated with Sr89 and patients with a pretreatment KPS of 60 should be evaluated on a case-by-case basis to determine whether or not Sr89 represents the most reasonable treatment option for palliation of their bone pain.

Imaging of prostate cancer

Prostate cancer diagnosis and treatment is fast emerging as a major health care issue in the United States. However, there are great uncertainties about the value of specific tests and therapies. Imaging modalities play a major role in the current management of patients with prostate cancer and this role is likely to expand in the future. Transrectal ultrasound is used to identify nonpalpable lesions, direct systematic biopsies, determine gland volume and stage prostate cancers. For staging skeletal metastases, the bone scan is acknowledged as the best method, however controversy surrounds its routine use in patients with low prostate specific antigen (PSA) values. Computed tomography (CT) and transrectal ultrasound have limited value in detecting extracapsular disease but CT can be used in conjunction with percutaneous biopsy to identify nodal metastases. The role of Endorectal coil MRI is currently evolving in the wake of a disappointing multi-institutional trial but MRI still holds the most promise for accurately detecting local extent of prostate cancer. New radiolabeled techniques with monoclonal antibodies and peptide imaging are also having early but promising results. The role of imaging in prostate cancer is continuing to evolve as technology and knowledge about prostate cancer biology improves and health care economics force a more judicious use of imaging resources.

Bone pain palliation with strontium-89 in breast cancer patients with bone metastases and refractory bone pain

Fifteen patients with breast cancer and skeletal metastases who had bone pain refractory to opioid analgesics and who were not eligible for or had not responded to local field radiotherapy, were treated with strontium-89. All patients had received previous treatment with chemotherapy and radiotherapy for bone metastases. Severity of bone pain, sleeping pattern, mobility and dependency on analgesics were evaluated before and 4, 8 and 12 weeks after 89Sr administration. Patients received 2 MBq/kg (118-148 MBq) of 89Sr by i.v. injection. Pain relief and a reduction in analgesic requirements were observed in 7 of the 15 (47%) patients, with a reduction in the severity score from 34% to 71%. Duration of the response varied from 3 to 7 months. A decrease in peripheral blood cell count was observed in 11 patients: a 15%-66% reduction in white cell count and a 14%-75% reduction in platelet count were detected at 12 weeks after treatment in these patients. We conclude that 89Sr is effective (47% response rate) for bone pain palliation in patients with bone metastases from breast cancer. Dependency on opioid analgesics may be reduced in patients with refractory bone pain.