Samarium for osteoblastic bone metastases and osteosarcoma

Radium-223 Treatment Produces Prolonged Suppression of Resident Osteoblasts and Decreased Bone Mineral Density in Trabecular Bone in Osteoblast Reporter Mice

Radium 223 (Ra-223) is an α-emitting bone-homing radiopharmaceutical that targets tumor-induced osteoblasts and is used to reduce bone pain and prolong overall survival in men with bone-metastatic, castrate-resistant prostate cancer. However, increased fracture risk in skeletal sites with no bone metastasis has been observed in patients treated with Ra-223. Both luciferase- or green fluorescence protein (GFP)-labeled osteoblast reporter mice were used to monitor the effect of Ra-223 on resident osteoblasts and normal bone structure. Upon Ra-223 treatment, 70% of resident osteoblasts were reduced within 2 days, and the osteoblast reduction lasted for at least 18 weeks without detectable recovery, as measured by in vivo bioluminescent imaging. In GFP-labeled osteoblast reporter mice, Ra-223 mainly reduced osteoblasts localized in the trabecular bone areas; the osteoblasts in the growth plates were less affected. Micro-computed tomography analyses showed that Ra-223 significantly reduced bone mineral density and bone microstructure in the trabecular area of femurs but not in the cortical bone. Tumor-induced bone was generated by inoculating osteogenic TRAMP-BMP4 prostate cancer cells into the mouse femurs; Ra-223 treatment significantly reduced tumor-induced osteoblasts. Our study shows that Ra-223 affects bone structures that are not involved in bone metastasis. Strategies that improve bone health may reduce fracture risk in patients receiving Ra-223.

Combination Therapy, a Promising Approach to Enhance the Efficacy of Radionuclide and Targeted Radionuclide Therapy of Prostate and Breast Cancer

In recent years, radionuclide therapy (RT) and targeted radionuclide therapy (TRT) have gained great interest in cancer treatment. This is due to promising results obtained in both preclinical and clinical studies. However, a complete response is achieved in only a small percentage of patients that receive RT or TRT. As a consequence, there have been several strategies to improve RT and TRT outcomes including the combination of these treatments with other well-established anti-cancer therapies, for example, chemotherapy. Combinations of RT and TRT with other therapies with distinct mechanisms of action represent a promising strategy. As for prostate cancer and breast cancer, the two most prevalent cancer types worldwide, several combination-based therapies have been evaluated. In this review, we will provide an overview of the RT and TRT agents currently used or being investigated in combination with hormone therapy, chemotherapy, immunotherapy, and external beam radiation therapy for the treatment of prostate cancer and breast cancer.

Neutron Activated 153Sm Sealed in Carbon Nanocapsules for in Vivo Imaging and Tumor Radiotherapy

Radiation therapy along with chemotherapy and surgery remain the main cancer treatments. Radiotherapy can be applied to patients externally (external beam radiotherapy) or internally (brachytherapy and radioisotope therapy). Previously, nanoencapsulation of radioactive crystals within carbon nanotubes, followed by end-closing, resulted in the formation of nanocapsules that allowed ultrasensitive imaging in healthy mice. Herein we report on the preparation of nanocapsules initially sealing "cold" isotopically enriched samarium (152Sm), which can then be activated on demand to their "hot" radioactive form (153Sm) by neutron irradiation. The use of "cold" isotopes avoids the need for radioactive facilities during the preparation of the nanocapsules, reduces radiation exposure to personnel, prevents the generation of nuclear waste, and evades the time constraints imposed by the decay of radionuclides. A very high specific radioactivity is achieved by neutron irradiation (up to 11.37 GBq/mg), making the "hot" nanocapsules useful not only for in vivo imaging but also therapeutically effective against lung cancer metastases after intravenous injection. The high in vivo stability of the radioactive payload, selective toxicity to cancerous tissues, and the elegant preparation method offer a paradigm for application of nanomaterials in radiotherapy.

Radiopharmaceuticals for Treatment of Osteosarcoma

Although trace amounts of radioactivity are routinely used to detect osteosarcoma, the use of larger therapeutic amounts of radiation is often an unrecognized opportunity to treat metastatic osteosarcoma. This chapter will review a number of approaches to use ionizing radiation in the form of injectable radiopharmaceuticals. Since bone metastases are a common pattern of metastatic spread of cancer in general, a number of bone-seeking radiopharmaceuticals have been developed and FDA approved for treatment of bone metastases. Although osteosarcoma, a bone-forming cancer, would seem ideally suited to be treated with bone seekers, patterns of relapse involving non-ossifying metastases remain a major problem to be overcome. Thus, this review will not only describe experience using a number of bone-seeking radiopharmaceuticals such as 153-samarium-EDTMP, 153-samarium-DOTMP, and 223-radium against osteosarcoma, but also approaches to identify patients who may benefit as well as some means to the improve overall efficacy including combination therapy with routine agents and using nuclear imaging to develop best strategy for use. These include imaging with not only ^99mTc-MDP standard bone scans, but also ^99mTc-MDP bone scans with SPECT CT, bone-specific sodium fluoride PET-CT (Na¹⁸F), and ¹⁸FDG-PET-CT. Accurate knowledge of oligometastatic active disease can facilitate more effective use of combination therapy, including radiosensitizers and local control measures, for example, stereotactic body radiotherapy (SBRT) and/or cryoablation to reduce disease burden as well as manage and prevent micrometastatic disease from growing and metastasizing. Finally, a new tumor-specific radiopharmaceutical, CLR 131, may also provide another radiopharmaceutical to treat both osteoblastic and non-ossifying areas of osteosarcoma.

Alpha Particle Radium 223 Dichloride in High-risk Osteosarcoma: A Phase I Dose Escalation Trial

PURPOSE

The prognosis of metastatic osteosarcoma continues to be poor. We hypothesized that alpha-emitting, bone-targeting radium 223 dichloride (²²³RaCl₂) can be safely administered to patients with osteosarcoma and that early signals of response or resistance can be assessed by quantitative and qualitative correlative imaging studies and biomarkers.

PATIENTS AND METHODS

A 3+3 phase I, dose-escalation trial of ²²³RaCl₂ (50, 75, and 100 kBq/kg) was designed in patients with recurrent/metastatic osteosarcoma aged ≥15 years. Objective measurements included changes in standardized uptake values of positron emission tomography (PET; 18FDG and/or NaF-18) and single-photon emission CT/CT (99mTc-MDP) as well as alkaline phosphatase and bone turnover markers at baseline, midstudy, and the end of the study.

RESULTS

Among 18 patients enrolled (including 15 males) aged 15-71 years, tumor locations included spine (n = 12, 67%), pelvis (n = 10, 56%), ribs (n = 9, 50%), extremity (n = 7, 39%), and skull (n = 2, 11%). Patients received 1-6 cycles of ²²³RaCl₂; cumulative doses were 6.84-57.81 MBq. NaF PET revealed more sites of metastases than did FDG PET. One patient showed a metabolic response on FDG PET and NaF PET. Four patients had mixed responses, and one patient had a response in a brain metastasis. Bronchopulmonary hemorrhage from Grade 3 thrombocytopenia (N = 1) was a DLT. The median overall survival time was 25 weeks.

CONCLUSIONS

The first evaluation of the safety and efficacy of an alpha particle in high-risk osteosarcoma shows that the recommended phase II dose for ²²³RaCl₂ in osteosarcoma is 100 kBq/kg monthly (twice the dose approved for prostate cancer), with minimal hematologic toxicity, setting the stage for combination therapies.

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.

Lanthanide complexes with phenanthroline-based ligands: insights into cell death mechanisms obtained by microscopy techniques

The biological properties of four lanthanide complexes with phenanthroline derivatives in ovarian cancer cells.

Current therapeutic options in metastatic castration-resistant prostate cancer

BACKGROUND

The tumors of many patients with prostate cancer eventually become refractory to androgen deprivation therapy with progression to metastatic castration-resistant disease. Significant advances in the treatment of metastatic castration-resistant prostate cancer (mCRPC) have been made in recent years, and new treatment strategies have recently been made available. The aim of this report was to schematically review all the approved pharmacologic treatment options for patients with mCRPC through 2018, analyzing the efficacy and possible side effects of each therapy to assist clinicians in reaching an appropriate treatment decision. New biomarkers potentially of aid in the choice of treatment in this setting are also briefly reviewed.

METHODS

We performed a literature search of clinical trials of new drugs and treatments for patients diagnosed with mCRPC published through 2018.

RESULTS

Two new hormonal drugs, abiraterone acetate and enzalutamide have been approved by FDA in 2011 and 2012, respectively for the treatment of patients with mCRPC and have undergone extensive testing. While these treatments have shown a benefit in progression-free and overall survival, the appropriate sequencing must still be determined so that treatment decisions can be made based on their specific clinical profile. Cabazitaxel has been shown to be an efficient therapeutic option in a postdocetaxel setting, while its role in chemotherapy-naïve patients must still be determined. Sipuleucel-T and radium-223 have been studied in patients without visceral metastases and have achieved overall survival benefits with good safety profiles. The feasibility and efficacy of combinations of new treatments with other known therapies such as chemotherapy are currently under investigation.

CONCLUSIONS

Drug development efforts continue to attempt to prolong survival and improve quality of life in the mCRPC setting, with several therapeutic options available. Ongoing and future trials are needed to further assess the efficacy and safety of these new drugs and their interactions, along with the most appropriate sequencing.

Treatment of Metastatic Bone Disease and the Emerging Role of Radium-223

Bone metastases are common in advanced malignancy and, despite the developments in both anticancer and bone-targeted therapies in recent years, new therapeutic strategies are still needed. Traditionally, radioisotopes have been rarely used in part owing to concerns about bone marrow toxicity that limits retreatment and may prevent safe administration of subsequent chemotherapy. Radium-223 dichloride (Ra-223) is a calcium mimetic that binds preferentially to newly formed bone in areas of bone metastases, is the first alpha-emitting radionuclide to be developed for clinical use, and is approved for treatment of castration-resistant prostate cancer and symptomatic bone metastases. In this setting, it improves overall survival and delays symptomatic skeletal complications. The high linear energy transfer of the emitted alpha particles causes predominantly nonrepairable double-stranded deoxyribonucleic acid breaks in tumor cells, and the large size of the alpha particle, compared with other forms of radiation, results in a short path length and highly localized tissue destruction. As a result, Ra-223 has a highly favorable safety profile with a low level of myelosuppression. The role of Ra-223 in malignancy is discussed and the prospects for future development outlined.

Bone Sarcomas in Pediatrics: Progress in Our Understanding of Tumor Biology and Implications for Therapy

The pediatric bone sarcomas osteosarcoma and Ewing sarcoma represent a tremendous challenge for the clinician. Though less common than acute lymphoblastic leukemia or brain tumors, these aggressive cancers account for a disproportionate amount of the cancer morbidity and mortality in children, and have seen few advances in survival in the past decade, despite many large, complicated, and expensive trials of various chemotherapy combinations. To improve the outcomes of children with bone sarcomas, a better understanding of the biology of these cancers is needed, together with informed use of targeted therapies that exploit the unique biology of each disease. Here we summarize the current state of knowledge regarding the contribution of receptor tyrosine kinases, intracellular signaling pathways, bone biology and physiology, the immune system, and the tumor microenvironment in promoting and maintaining the malignant phenotype. These observations are coupled with a review of the therapies that target each of these mechanisms, focusing on recent or ongoing clinical trials if such information is available. It is our hope that, by better understanding the biology of osteosarcoma and Ewing sarcoma, rational combination therapies can be designed and systematically tested, leading to improved outcomes for a group of children who desperately need them.

Recent advances in the management of osteosarcoma and forthcoming therapeutic strategies

Osteosarcoma is the most frequent primary bone tumor and occurs mainly in young patients (average age: 18 years). No evolution of the survival rates has been recorded for two decades in response to current treatment, associating often toxic and badly tolerated cures of chemotherapy (given a significant rate of bad responders) with preserving surgery. Among the proposed innovative strategies, immune-based therapy, antiangiogenesis agents, tumor-suppressor or suicide gene therapy, or anticancer drugs not commonly used in osteosarcoma are presented. A further strategy is to target the tumor microenvironment rather than the tumor itself.

Bone-seeking radiopharmaceuticals as targeted agents of osteosarcoma: samarium-153-EDTMP and radium-223

Osteosarcoma is a cancer characterized by formation of bone by malignant cells. Routine bone scan imaging with Tc-99m-MDP is done at diagnosis to evaluate primary tumor uptake and check for bone metastases. At time of relapse the Tc-99m-MDP bone scan also provides a specific means to assess formation of bone by malignant osteosarcoma cells and the potential for bone-seeking radiopharmaceuticals to deliver radioactivity directly into osteoblastic osteosarcoma lesions. This chapter will review and compare a bone-seeking radiopharmaceutical that emits beta-particles, samarium-153-EDTMP, with an alpha-particle emitter, radium-223. The charged alpha particles from radium-223 have far more mass and energy than beta particles (electrons) from Sm-153-EDTMP. Because radium-223 has less marrow toxicity and more radiobiological effectiveness, especially if inside the bone forming cancer cell than samarium-153-EDTMP, radium-223 may have greater potential to become widely used against osteosarcoma as a targeted therapy. Radium-223 also has more potential to be used with chemotherapy against osteosarcoma and bone metastases. Because osteosarcoma makes bone and radium-223 acts like calcium, this radiopharmaceutical could possibly become a new targeted means to achieve safe and effective reduction of tumor burden as well as facilitate better surgery and/or radiotherapy for difficult to resect large, or metastatic tumors.

Beyond Palliation: Therapeutic Applications of 153Samarium-EDTMP

Primary and metastatic malignant bone lesions result in significant pain and disability in oncology patients. Targeted bone-seeking radioisotopes including ¹⁵³Samarium ethylene-diamine-tetramethylene-phosphonic acid (¹⁵³Sm-EDTMP) have been shown to effectively palliate bone pain, often when external beam radiotherapy (EBRT) is not feasible. However, recent evidence also suggests ¹⁵³Sm-EDTMP has cytotoxic activity either alone or in combination with chemotherapy or EBRT. ¹⁵³Sm-EDTMP may be useful as anti-neoplastic therapy apart from pain palliation in a variety of malignancies. For prostate cancer patients, several phase I and II clinical trials have shown that combined ¹⁵³Sm-EDTMP and docetaxel-based chemotherapy can result in >50% decrease in prostate-specific antigen with manageable myelosuppression. In hematologic malignancies, ¹⁵³Sm-EDTMP produced clinical responses when combined with bortezomib in multiple myeloma. ¹⁵³Sm-EDTMP also can be used with myeloablative chemotherapy for marrow conditioning prior to stem cell transplant. In osteosarcoma, ¹⁵³Sm-EDTMP infusion delivers radiation to multiple unresectable lesions simultaneously and provides local cytotoxicity without soft tissue damage that can be combined with chemotherapy or radiation. Prior to routine incorporation of ¹⁵³Sm-EDTMP into therapeutic regimens, we must learn how to ensure optimal delivery to tumors, determine which patients are likely to benefit, improve our ability to assess clinical response in bone lesions and further evaluate the efficacy ¹⁵³Sm-EDTMP in combination with chemotherapy, radiation and novel targeted agents.

A pilot safety trial investigating a vector-based vaccine targeting carcinoembryonic antigen in combination with radiotherapy in patients with gastrointestinal malignancies metastatic to the liver

OBJECTIVE

Previous studies have demonstrated the ability of non-lethal doses of radiation to alter the phenotype of tumor cells to facilitate immune mediated killing. This pilot study evaluated the tolerability of a vector-based vaccine targeting carcinoembryonic antigen (CEA) in combination with radiation therapy in patients with gastrointestinal malignancies metastatic to the liver.

METHODS

Patients enrolled had progressive CEA(+) tumors with metastatic liver lesions. Patients had received a median of three previous chemotherapy regimens, with a median of 2 months since their last chemotherapy regimen. Only 58% had metastatic disease limited to the liver. Vaccination commenced day 1 with biweekly boosters and split-course radiation (total 32 Gy) starting on day 21. Blood was collected at baseline and day 91 for immunological analysis.

RESULTS/CONCLUSION

A total of 12 patients were enrolled. There were no grade 3 or greater toxicities or grade 2 or greater hepatic toxicities. Median time on-study was 3 months, with the longest time on treatment being 5 months (n = 2). Immunological analysis was limited to two patients; neither showed an increase above baseline in CEA-specific T cells post-therapy. CEA/TRICOM vaccination in combination with low-dose radiation therapy is safe. There was limited evidence of activity in this patient population.

Phase 2 trial of two courses of cyclophosphamide and etoposide for relapsed high-risk osteosarcoma patients

BACKGROUND

A phase 2 trial was carried out to assess the antineoplastic activity of 2 courses of cyclophosphamide-etoposide in relapsed osteosarcoma patients.

METHODS

Twenty-six relapsed osteosarcoma patients with a median age of 18.5 years (8.3-47.1) were enrolled. Seven patients were in first relapse (27%), 11 in second relapse (42%), 7 in third relapse (27%), and 1 in fourth relapse (4%). Eighteen patients had bone metastasis at study entry (69%). Cyclophosphamide was given at 4 g/m(2) on Day 1 followed by etoposide at 200 mg/m(2) on Days 2, 3, and 4. Second cyclophosphamide and etoposide was planned at 21 days to 28 days from the previous one. The primary endpoint of the study was the clinical benefit at 4 months measured as progression-free survival.

RESULTS

Progression-free survival at 4 months was 42%. Five patients achieved responses (19%), 9 patients had stable disease (35%), and 12 had tumor progression (46%). Overall survival (OS) at 1 year was 50%. The only grade 4 extrahematological toxicities were fever (5%), acute bronchospasm (4%) and stomatitis (18%). Six patients (23%) underwent radical surgery after cyclophosphamide and etoposide x2.

CONCLUSIONS

Cyclophosphamide and etoposide x2 may arrest osteosarcoma progression in a significant number of patients (54%). Osteosarcoma progression arrest after cyclophosphamide and etoposide x2 translates in a better OS. Cyclophosphamide and etoposide x2 had good tolerability and the toxicity was time-limited and resolved in all cases.

Non-surgical treatment of pulmonary and extra-pulmonary metastases

Studies have demonstrated that chemotherapy alone is usually unsuccessful as exclusive therapy for osteosarcoma (Cancer 95:2202-2201, 2002). Information will be presented for situations where non-surgical alternatives could be considered as useful, if not necessary, adjuncts to chemotherapy. In the thorax these include treatment of pleural effusions, chest wall lesions, central lung or mediastinal osteosarcoma, as well as recurrences in patients with limited pulmonary reserve. Other situations include too many metastases to easily resect, axial osteosarcomas, bone metastases, liver and brain metastases. Non-surgical local control measures include radiation with chemotherapy for radiosensitization, bone-seeking radioisotopes (e.g., 153Sm-EDTMP, 223Ra), bisphosphonates, heat (radiofrequency ablation), freezing and thawing (cryoablation), and intracavitary or regional (aerosol) therapy. Because of the predictable and common pattern of pulmonary metastases in osteosarcoma, aerosol therapy also offers an attractive regional treatment strategy. Principles and use of aerosol cytokines (e.g., GM-CSF, IL-2), and aerosol chemotherapy with gemcitabin will be discussed. Individual cases illustrating strategy and techniques will be presented.

Multimodality treatment of osteosarcoma: radiation in a high-risk cohort

PURPOSE

Chemotherapy during radiation and/or bone-seeking radioisotope therapy (153-samarium; 1 mCi/kg) during radiation may improve osteosarcoma cancer control.

PATIENTS AND METHODS

We analyzed our preliminary radiation experience in high-risk, metastatic, and/or recurrent patients during a consecutive period of 20 months (May 2005-December 2006).

RESULTS

Thirty-nine high-risk osteosarcoma patients had radiotherapy; 119 sites were irradiated. A median four sites were irradiated per patient (range 1-14). The median radiation dose and number of fractions of radiation was 30 Gy in 10 fractions (range 10-70 Gy in 4-35 fractions). Chemotherapy, most commonly ifosfamide or methotrexate, was used in 80% (100/119) radiotherapy courses. Of 38 painful sites, 29 had improvement (76%), 4 had no change (10%), and 5 had more pain (13%). Objective and potentially durable responses were documented using PET-CT and bone scans with persistent and sustained reduction of standard uptake values (SUVs; initial SUV of indication lesion 9.5 became <4 at all subsequent time points) and serial bone scans [improvement in 29/39 (72%); stable 10/39 (25%), worse 1/39 (3%)]. The actuarial 4-year survival from development of metastasis was 39%.

CONCLUSIONS

Our early results suggest that the use of multimodality therapy including chemotherapy with radiation in unresectable osteosarcoma may be beneficial.

Effects of increasing doses of samarium-153-ethylenediaminetetramethylene phosphonate on axial and appendicular skeletal growth in juvenile rabbits

INTRODUCTION

Targeted radiotherapy using samarium-153-ethylenediaminetetramethylene phosphonate (153 Sm-EDTMP) is currently under investigation for treatment of osteosarcoma. Osteosarcoma often occurs in children, and previous studies on a juvenile rabbit model demonstrated that clinically significant damage to developing physeal cartilage may occur as a result of systemic 153 Sm-EDTMP therapy. The aim of this study was to evaluate the late effects of 153 Sm-EDTMP on skeletal structures during growth to maturity and to determine if there is a dose response of 153 Sm-EDTMP on growth of long bones.

METHODS

Female 8-week-old New Zealand white rabbits were divided into three treatment groups plus controls. Each rabbit was intravenously administered a predetermined dose of 153 Sm-EDTMP. Multiple bones of each rabbit were radiographed every 2 months until physeal closure, with subsequent measurements made to assess for abbreviated bone growth. Statistical analyses were performed to determine the differences in bone length between groups, with significance set at P<.05.

RESULTS

Significant differences in lengths of multiple bones were detected between the high-dose group and other treatment groups and controls at each time interval. A significant difference in lengths of the tibias was also noted in the medium-treatment group, compared to controls. Mean reduction of bone length was first detected at 4 months and did not increase significantly over time.

CONCLUSIONS

These data suggest that clinically significant bone shortening may occur as a result of high-dosage administration of 153 Sm-EDTMP. Further investigation regarding the effects of bone-seeking radiopharmaceuticals on bone growth and physeal cartilage is warranted.

Samarium lexidronam (153Sm-EDTMP): skeletal radiation for osteoblastic bone metastases and osteosarcoma

Radiation therapy can be an effective means to treat bone metastases, which occur in more than 50% of cancer patients. (153)Samarium lexidronam ((153)Sm-EDTMP; Quadramet, Cytogen) is a radiopharmaceutical designed for deposition into bone metastases. Bone scans can identify patients that may benefit from targeted radiation therapy with (153)Sm-EDTMP. As an unsealed source of radiation therapy, (153)Sm-EDTMP is simple to administer: 1 mCi/kg is given in a similar fashion to a bone scan injection ((99m)Tc-MDP bone scan injection is given at 0.2-0.35 mCi/kg. Therefore, both are administered intravenously. However, the radiation-absorbed dose and radiopharmaceutical energy are different). Nevertheless, despite simplicity of administration, (153)Sm-EDTMP is underutilized for improving cancer pain in the skeleton. Repeated cycles and combined treatment with other modalities such as bisphosphonates, chemotherapy and/or external beam radiation are possible. (153)Sm-EDTMP combined with bisphosphonates, chemotherapy and/or radiation may provide better palliation of bone metastases and also in bone-forming tumors (osteosarcoma). Encouraging experience using high-dose (153)Sm-EDTMP for total marrow irradiation in hematologic malignancies involving the bones (e.g., myeloma or acute leukemia) is also reviewed.

Outpatient Chemotherapy plus Radiotherapy in Sarcomas: Improving Cancer Control with Radiosensitizing Agents

Background

Cancer control by radiotherapy (RT) can be improved with concurrent chemotherapy. Outpatient strategies for sarcomas that combine chemotherapy and RT are possible since supportive care and RT techniques have improved.

Methods

The current status of non-anthracycline chemotherapy in combination with radiation for high-risk sarcoma is reviewed.

Results

Ifosfamide with mesna and newer activated ifosfamide agents (ZIO-201 and glufosfamide) have high potential to improve sarcoma cancer control. In Ewing's sarcoma and osteosarcoma, high-dose ifosfamide with mesna (2.8 g/m2/day of each x 5 days; mesna day 6) can be safely given to outpatients using continuous infusion. Reducing ifosfamide nephrotoxicity and central nervous system side effects are discussed. Other outpatient radiosensitization regimens include gemcitabine (600–1000 mg/m2/dose IV over 1 hour weekly x 2–3 doses), temozolomide (75 mg/m2/daily x 3–6 weeks), or temozolomide (100 mg/m2/dose daily x 5) + irinotecan (10 mg/m2/dose daily x 5 x 2 weeks). In osteosarcoma with osteoblastic metastases on bone scan, samarium (1 mCi/kg; day 3 of RT) and gemcitabine (600 mg/m2 IV over 1 hour day 9 of RT) is a radiosensitization strategy. Future drugs for radiosensitization include beta-D-glucose targeted activated ifosfamide (glufosfamide) and sapacitabine, an oral nucleoside with in vitro activity against solid tumors including sarcomas.

Conclusions

The potential to treat major causes of sarcoma treatment failure (local recurrence and distant metastases) with concurrent chemotherapy during radiation should be considered in high-grade sarcomas.

Clinical benefit of bone-targeted radiometabolic therapy with 153Sm-EDTMP combined with chemotherapy in patients with metastatic hormone-refractory prostate cancer

BACKGROUND

Bone metastases are responsible for most of the morbidity associated with hormone-refractory prostate cancer (HRPC). 153Sm-ethylenediaminetetramethylene phosphonate (153Sm-EDTMP) has been approved for palliation of painful skeletal metastases. We retrospectively investigated the possible synergistic effect on survival of 153Sm-EDTMP (given to HRPC patients for bone pain palliation) and chemotherapy.

METHODS

Forty-five HRPC patients were evaluated, with a median age of 71 years. The number of metastatic bone sites was <or=10 in 25 patients and >10 in 20 patients. Median serum PSA was 224 ng/ml. Bone pain was mild in 6 patients, moderate in 16, severe in 22 and intolerable in 1. Fifteen patients were only treated with 153Sm-EDTMP (group A), while 30 patients also received chemotherapy (estramustine phosphate or mitoxantrone plus prednisone) at variable times: between 3 and 5 months after 153Sm-EDTMP (14 patients, group B) or within 1 month after 153Sm-EDTMP (16 patients, group C).

RESULTS

Haematological toxicities observed after either regimen were in general mild, consistent with common observations after either 153Sm-EDTMP or chemotherapy, and without any additive adverse effects in the patients receiving both 153Sm-EDTMP and chemotherapy. Bone pain palliation to some degree was induced by 153Sm-EDTMP in 32/45 patients (71.1%), the proportion of patients with a favourable clinical response being significantly higher in group C than in group A (87.5% vs 53.3%, p = 0.0388). Also in terms of biochemical response (serum PSA levels), patients of group C performed significantly better than patients of group A (p = 0.0235). Overall median survival from the time of administration of 153Sm-EDTMP was 15 months in the total cohort of 45 patients, and was significantly longer in group C than in either group B (30 months vs 11 months, p = 0.023) or group A (30 months vs 10 months, p = 0.008).

CONCLUSION

The results of this study confirm that 153Sm-EDTMP is effective in terms of pain relief and PSA response, with minimal toxicity. When it was administered in combination with chemotherapy, prolonged survival indicated actual clinical benefit, while there were no additive toxicities. These results provide the rationale for future prospective evaluation of combined therapeutic strategies.

Improving outcomes in difficult bone cancers using multimodality therapy, including radiation: Physician and nursing perspectives

Principles of therapy are similar for Ewing's sarcoma and osteosarcoma. Chemotherapy or surgery alone cures few patients. Multimodality measures are needed for durable response. Quality of life and function are very important short- and long-term considerations. The spine, sacrum, pelvis, ankle, hand, mediastinum, pulmonary hilum, and chest wall are examples of bone cancer locations for which surgery is difficult. Patients with positive margins may need radiation and may experience systemic therapy delay, recurrence, loss of function, or any combination of these. When radiation is used as a means of local control, concomitant chemotherapy can increase its effectiveness. Options for difficult Ewing's sarcoma and osteosarcoma situations and multimodality solutions, including 1 mCi/kg of samarium and proton therapy, are discussed. Combination radiation and chemotherapy regimens are summarized, and organization of patients, caregivers, and medical teams for multimodality therapy is described, along with tools used in our institution that aid in this process.