The use of strontium 89 for palliation of pain from bone metastases associated with hormone-refractory prostate cancer

Radionuclide Therapy for Bone Metastases: Utility of Scintigraphy and PET Imaging for Treatment Planning

The skeleton is a common site for cancer metastases. Bone metastases are a major cause of morbidity and mortality and associated with pain, pathologic fractures, spinal cord compression, and decreased survival. Various radionuclides have been used for pain therapy. Recently, an α-emitter has been shown to improve overall survival of patients with bone metastases from castration-resistant prostate cancer and was approved as a therapeutic agent. The aim of this article is to provide an overview regarding state of the art radionuclide therapy options for bone metastases, with focus on the role of PET imaging in therapy planning.

Preparation and evaluation of rhenium-188-pamidronate as a palliative treatment in bone metastasis

OBJECTIVE

Rhenium-188-hydroxyethylidene diphosphonate (¹⁸⁸Re-HEDP) as a first generation bisphosphonate has been widely used for bone seeking radiopharmaceutical in cases of metastatic bone disease. No study has been yet reported on preparing a complex of ¹⁸⁸Re with pamidronate (3-aminohydroxypropylidene-1,1-bisphosphonic acid) (PMA) as a second generation bisphosphonate. Based on this fact, it was hypothesized that a bone-seeking ¹⁸⁸Re-PMA radiopharmaceutical could be developed as an agent for palliative radiotherapy of bone pain due to skeletal metastases.

METHODS

Pamidronate was labeled with ¹⁸⁸ReO₄^- eluted from the alumina based ¹⁸⁸W/¹⁸⁸Re generator. Labeling was optimized, and radiochemical analysis was performed by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). Biodistribution of this radioconjugate was evaluated and verified further in mice.

RESULTS

¹⁸⁸Re-PMA was prepared successfully in a high labeling yield (˃95%) corresponding to a specific activity of 124MBq/μmol and good in vitro stability, but it is likely to consist of multiple species. In biodistribution studies selective uptake and retention of activity in the skeletal system (0.81±0.25% ID/g and 0.57±0.16 at 4 and 48h in bone post injection respectively) followed by clearance in the soft tissues were observed.

CONCLUSION

These results show that due to its biological capabilities it would be advantageous to use ¹⁸⁸Re-PMA for bone pain palliation therapy.

Targeted α-particle therapy of bone metastases in prostate cancer

Medical oncology is moving toward personalized and precision treatments. This evolution is spearheaded by ongoing discoveries on the fundamental machinery that controls tumor and hosts microenvironment biological behavior. α-Particles with their high energy and short range had long been recognized as potentially useful in the treatment of cancer. More than a century after the discovery of radium by the Curies, 223Ra dichloride is now available in the expanding armamentarium of therapies for metastatic castration-resistant prostate cancer. This advance occurs in the context of several other novel therapeutics in advanced prostate cancer that include more effective androgen receptor pathway inhibition, better chemotherapy, and immunotherapy. We present a concise review on the therapeutic use of 223Ra dichloride in this clinically important setting including excerpts on the radium history, physical properties, the alpharadin in symptomatic prostate cancer clinical trial, and practical information on its use in the clinic. It is anticipated that, with the current emergence of 223Ra as a viable form of therapy, interest in and use of α-particle therapy in the management of cancer will grow.

Prospective Evaluation of Samarium-153-EDTMP Radionuclide Treatment for Bone Metastases in Patients with Hormone-Refractory Prostate Cancer

PURPOSE

Bone is a common site of metastatic disease and the most frequent site of metastatic spread in patients with prostate cancer. Most patients with bone metastases complain of bone pains. This pain may be alleviated or eliminated by administration of radiotherapy at the site of metastases. Currently, two forms of radiotherapy administration exist: external-beam irradiation or intravenous administration of bone-seeking therapeutic radiopharmacon such as samarium-153-ethylene-diamino-tetramethylene-phosphonate (EDTMP). This radiopharmacon produces beta-particles and concentrates in the areas of enhanced osteoblastic activity. The aim of this study was to assess the efficacy of (153)Sm-EDTMP therapy.

MATERIALS AND METHODS

32 men (aged 50-83, mean 70 years) with bone disseminated hormone-refractory prostate cancer and bone pain received (153)Sm-EDTMP. Mean applied dosage was 40 MBq/kg of the patient's body weight. Karnofsky performance status, pain score (numerical rating scale), analgesic score (WHO) and blood count were evaluated before, and 1 and 3 months after the treatment.

RESULTS

Significant pain relief was observed in 44 and 38% of patients, mild relief in 31 and 34% and no effect in 25 and 28% of patients, 1 and 3 months after administration, respectively. Pain palliation was accompanied by an improvement in mobility and a decrease in necessary dosage of analgesics. Mild and transient bone marrow suppression was observed as a side effect of (153)Sm-EDTMP treatment. None of the patients showed hematological toxicity grade 4, and only 2 showed grade 3 (NCI CTC). The majority of the patients had hematological toxicity grade 1 or 2.

CONCLUSION

After (153)Sm-EDTMP administration, bone pain palliation was observed in 72% of patients for 3 months. Hematological toxicity after (153)Sm-EDTMP treatment was mild and transient.

Rhenium-188-HEDP in the palliative treatment of bone metastases

INTRODUCTION

Rhenium-188-HEDP (188Re-HEDP) is a new and attractive radiopharmaceutical for the treatment of bone pain due to metastases. As a product of a 188W/188Re generator it is convenient for clinical use. With a short physical half life of 16.9 hours and a maximal beta-energy of 2.1 MeV, it is suitable for therapy.

METHODS

We investigated the influence of 188Re-HEDP on pain relief, analgesic intake and impairment of bone marrow function in 15 patients. All patients were interviewed using standardized questions before, and 1, 2, 3, 4, 8, and 12 weeks after therapy. Blood samples were drawn weekly for 12 weeks, and a blood count was performed. Patients underwent gamma camera imaging to determine the radionuclide accumulation 4, 20, and 28 hours after therapy. The patients were treated with 1600 to 3459 MBq of 188Re-HEDP.

RESULTS

Patients showed an improvement of the Karnofsky performance index from 74 +/- 8% to 84 +/- 11% 12 weeks after therapy. This improvement was statistically significant (p = 0.001). Eighty percent of the patients described pain relief and reduction of analgesics. Twenty percent of the patients could discontinue their analgesics. Mean platelet count decreased from (284 +/- 84)*10(3)/microliter to (205 +/- 62)*10(3)/microliter, and mean leukocyte count from (7.5 +/- 1.5)*10(3)/microliter to (5.9 +/- 2.1)*10(3)/microliter after therapy. The maximal differences between the values of platelets and leukocytes before and after therapy were not statistically significant (p = 0.021 and p = 0.094). Prostate specific antigen decreased from 95 +/- 83 ng/ml to 41 +/- 21 ng/ml, the difference was not statistically significant (p = 0.443). The bone accumulation 4, 20, and 28 hours after therapy was 1.3 +/- 0.5%, 0.6 +/- 0.3%, and 0.45 +/- 0.2% of the injected dose of a single metastasis, and 57 +/- 17%, 15.5 +/- 2% and 11 +/- 3% in the whole body, respectively. The effective half-life of 188Re-HEDP was 15.3 +/- 3.0 hours in the bone metastases, and 11.4 +/- 2.8 hours in the whole body. This corresponds to a residence time of 0.22 +/- 0.25 hours in the bone metastases, and of 10.54 +/- 2.59 hours in the whole body.

CONCLUSION

In a small patient population, 188Re-HEDP therapy for bone pain palliation was effective and was associated with minimal toxicity.

Radiotherapy for the palliation of prostate cancer

The large population of men who will develop metastatic prostate cancer creates a strong need for good palliative care. For many men, androgen ablation works well; however, when this fails, the quality of a man's life can quickly degrade. Pain from skeletal metastases, neurologic involvement, bleeding, and obstruction can all occur. Radiotherapy has long been the gold standard for palliation of symptomatic disease. However, a new approach using hemibody irradiation (HBI) earlier in the disease course, as well as more effective and tolerable dose and fractionation schemes for local field radiation, are providing excellent amelioration of symptoms and the possibility of living longer and more comfortably to many men with metastatic prostate cancer. The indications and use of therapeutic systemic radioisotopes to help achieve these objectives are also discussed.

Symptomatic metabolic radiotherapy (with Sr-89) of bone metastases in prostatic cancer. Personal experience

The authors report their experience with 20 patients subjected to metabolic radiotherapy with Sr-89 for palliation of bone metastases in advanced prostatic cancer. Sr-89 is an effective symptomatic treatment, generally well tolerated, with minimal adverse effects.

Selected topics in orthopedic nuclear medicine

Nuclear medicine provides information about bone physiology that complements anatomic imaging modalities. Following a review of the principles of bone scintigraphy, scintigraphic imaging of orthopedic problems, such as primary and secondary neoplastic disease of the skeleton, occult fracture, stress fracture, and osteomyelitis are discussed.

Advanced prostate cancer. Endocrine therapies and palliative measures

Management of patients with metastatic prostate cancer differs from that of patients with other metastatic solid tumors. Because the treating physician is usually the patient's urologist, the primary care physician's main role may be to relieve pain and treat the patient for common side effects of hormone therapies. By being familiar with the forms of systemic treatment-including orchiectomy and the use of estrogens, luteinizing hormone-releasing hormone agonists, and antiandrogens-the primary care physician can also assist patients in making treatment decisions that are individualized to the specifics of disease state, comorbid conditions, age, and value systems.

Treatment of Androgen-Independent Prostate Cancer

Androgen-ablative therapy for metastatic prostate cancer is effective for 60%-80% of men, but its effects are always finite and the majority of men develop androgen-independent disease within two years. Although current therapies for androgen-independent disease have not been shown to impact on survival, recent clinical and laboratory insights offer hope for effective therapy. For instance, recent data indicate that androgen-independent disease may still be dependent on hormonal stimulation, suggesting that hormonally based therapies may provide continued benefit. Chemotherapy, especially with estramustine and etoposide, seems to be an effective combination for a majority of patients. Treatment with suramin had been hampered by its side effects, but new dosing schedules are effectively circumventing toxicity. Radioisotopes such as strontium 89 have been shown to provide effective palliation for a majority of androgen-independent patients. Overall, these and other emerging efforts may be the foundation for therapies that offer hope for a significant survival benefit.