Management of painful bone metastases

Cabozantinib inhibits prostate cancer growth and prevents tumor-induced bone lesions

PURPOSE

Cabozantinib, an orally available multityrosine kinase inhibitor with activity against mesenchymal epithelial transition factor (MET) and VEGF receptor 2 (VEGFR2), induces resolution of bone scan lesions in men with castration-resistant prostate cancer bone metastases. The purpose of this study was to determine whether cabozantinib elicited a direct antitumor effect, an indirect effect through modulating bone, or both.

EXPERIMENTAL DESIGN

Using human prostate cancer xenograft studies in mice, we determined the impact of cabozantinib on tumor growth in soft tissue and bone. In vitro studies with cabozantinib were performed using (i) prostate cancer cell lines to evaluate its impact on cell growth, invasive ability, and MET and (ii) osteoblast cell lines to evaluate its impact on viability and differentiation and VEGFR2.

RESULTS

Cabozantinib inhibited progression of multiple prostate cancer cell lines (Ace-1, C4-2B, and LuCaP 35) in bone metastatic and soft tissue murine models of prostate cancer, except for PC-3 prostate cancer cells in which it inhibited only subcutaneous growth. Cabozantinib directly inhibited prostate cancer cell viability and induced apoptosis in vitro and in vivo and inhibited cell invasion in vitro. Cabozantinib had a dose-dependent biphasic effect on osteoblast activity and inhibitory effect on osteoclast production in vitro that was reflected in vivo. It blocked MET and VEGFR2 phosphorylation in prostate cancer cells and osteoblast-like cells, respectively.

CONCLUSION

These data indicate that cabozantinib has direct antitumor activity, and that its ability to modulate osteoblast activity may contribute to its antitumor efficacy.

Pathobiology and management of prostate cancer-induced bone pain: recent insights and future treatments

Prostate cancer (PCa) has a high propensity for metastasis to bone. Despite the availability of multiple treatment options for relief of PCa-induced bone pain (PCIBP), satisfactory relief of intractable pain in patients with advanced bony metastases is challenging for the clinicians because currently available analgesic drugs are often limited by poor efficacy and/or dose-limiting side effects. Rodent models developed in the past decade show that the pathobiology of PCIBP comprises elements of inflammatory, neuropathic and ischemic pain arising from ectopic sprouting and sensitization of sensory nerve fibres within PCa-invaded bones. In addition, at the cellular level, PCIBP is underpinned by dynamic cross talk between metastatic PCa cells, cellular components of the bone matrix, factors associated with the bone microenvironment as well as peripheral components of the somatosensory system. These insights are aligned with the clinical management of PCIBP involving use of a multimodal treatment approach comprising analgesic agents (opioids, NSAIDs), radiotherapy, radioisotopes, cancer chemotherapy agents and bisphosphonates. However, a major drawback of most rodent models of PCIBP is their short-term applicability due to ethical concerns. Thus, it has been difficult to gain insight into the mal(adaptive) neuroplastic changes occurring at multiple levels of the somatosensory system that likely contribute to intractable pain at the advanced stages of metastatic disease. Specifically, the functional responsiveness of noxious circuitry as well as the neurochemical signature of a broad array of pro-hyperalgesic mediators in the dorsal root ganglia and spinal cord of rodent models of PCIBP is relatively poorly characterized. Hence, recent work from our laboratory to develop a protocol for an optimized rat model of PCIBP will enable these knowledge gaps to be addressed as well as identification of novel targets for drug discovery programs aimed at producing new analgesics for the improved relief of intractable PCIBP.

High-intensity focused ultrasound plus concomitant radiotherapy: a new weapon in oncology?

The potential impact of high-intensity focused ultrasound (HIFU) to general medicine and oncology seems very high. However, while in the research area, the development of this technique is very rapid and unchallenged. The direct application of HIFU to human tumour therapy is hampered by various technical difficulties, which may confine its role to a marginal device in the surgery armamentarium. To deploy the full potential of focused ultrasound in oncology, it seems necessary to review the basic relationship between HIFU and external beam radiotherapy. This is the aim of the present work.

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.

Intense focused ultrasound preferentially stimulates subcutaneous and focal neuropathic tissue: preliminary results

OBJECTIVE

Potential peripheral sources of pain from subcutaneous tissue can require invasive evocative tests for their localization and assessment. Here, we describe studies whose ultimate goal is development of a noninvasive evocative test for subcutaneous, painful tissue.

DESIGN

We used a rat model of a focal and subcutaneous neuroma to test the hypothesis that intense focused ultrasound can differentiate focal and subcutaneous neuropathic tissue from control tissue. To do so, we first applied intense focused ultrasound (2 MHz, with individual pulses of 0.1 second in duration) to the rat's neuroma while the rat was under light anesthesia. We started with low values of intensity, which we increased until intense focused ultrasound stimulation caused the rat to reliably flick its paw. We then applied that same intense focused ultrasound protocol to control tissue away from the neuroma and assayed for the rat's response to that stimulation.

RESULTS

Intense focused ultrasound of sufficient strength (I(SATA) of 600 +/- 160 W/cm(2) ) applied to the neuroma caused the rat to flick its paw, while the same intense focused ultrasound applied millimeters to a centimeter away failed to induce a paw flick.

CONCLUSION

Successful stimulation of the neuroma by intense focused ultrasound required colocalization of the neuroma and intense focused ultrasound supporting our hypothesis.

A micro-imaging study linking bone cancer pain with tumor growth and bone resorption in a rat model

Bone metastases represent a frequent complication of advanced breast cancer. As tumor growth-induced bone remodeling progresses, episodes of severe pain and fractures of weight-bearing limbs increase. All of these skeletal-related events influence the patient's quality of life and survival. In the present study, we sought to determine whether some of these pain-related behaviors could be directly correlated to tumor progression and bone remodeling. For this purpose, we used a rat model of bone cancer pain based on the implantation of mammary carcinoma cells in the medullary cavity of the femur. The bone content and tumor growth were monitored over time by magnetic resonance imaging (MRI) and micro X-ray computed tomography (μCT). The same animals were evaluated for changes in their reflexive withdrawal responses to mechanical stimuli (allodynia) and weight-bearing deficits. As assessed by MRI, we found a negative correlation between tumor volume and allodynia or postural deficits throughout the experiment. Using μCT, we found that the bone volume/total volume (BV/TV) ratios for trabecular and cortical bone correlated with both mechanical hypersensitivity and weight-bearing impairment. However, whereas trabecular BV/TV stabilized between days 7 and 10 post-tumor detection, the cortical bone loss reached its maximum at that time. Our imaging approach also allowed us to consistently detect the tumor before the onset of pain, paving the way for the preemptive identification of at-risk patients. Altogether, these results improve our understanding of the events leading to tumor-induced bone pain and could eventually help in the design of novel strategies for the management of bone diseases.

[Evaluation of professional practices: improving cancer related-pain management in radiation oncology]

Radiation oncologist often faced cancer pain, regardless the stage of cancer. Given the high prevalence of cancer pain, and its potential for profound adverse consequences, all patients with active malignancy should be routinely screened and treated for pain. Using a questionnaire developed by the pain center of the Institut de cancérologie de la Loire, we questioned in a routine day 154 patients receiving radiation in our department. On 154 assessed patients, 92% (n = 143) were treated with curative intent and 8% (n = 11) with analgesic intent. Sixty-seven (44%) and 14 (9%) declared to feel pain outside and during radiotherapy, respectively. Using the visual analogic scale, 39, 41 and 20% rated their pain between 1 and 3, 4 and 6 and more than 7, respectively. One third of patients suffering from pain had no analgesic treatment and 55% of patients felt inadequately relieved. Almost all (97%) of these noted an impact on their quality of life. Half of them (54%) were aware of a specific consultation for pain. A pain consultation was offered to 19% of respondents and 26% of patients were referred for a specialized consultation at the end of the investigation. Despite the existence of a pain center in the Institute, the pain seems insufficiently assessed and supported for patients receiving radiation therapy. Better communication between caregivers and better information should enable a more comprehensive assessment and specific treatment for cancer-pain related.

Spinal metastasis in thyroid cancer

BACKGROUND

Thyroid carcinoma generally responds well to treatment and spinal metastasis is an uncommon feature. Many studies have looked at the management of spinal metastasis and proposed treatments, plans and algorithms. These range from well-established methods to potentially novel alternatives including bisphosphonates and vascular endothelial growth factor (VEGF) therapy, amongst others.The purposes of this systematic review of the literature are twofold. Firstly we sought to analyse the proposed management options in the literature. Then, secondly, we endeavoured to make recommendations that might improve the prognosis of patients with spinal metastasis from thyroid carcinomas.

METHODS

We conducted an extensive electronic literature review regarding the management of spinal metastasis of thyroid cancer.

RESULTS

We found that there is a tangible lack of studies specifically analysing the management of spinal metastasis in thyroid cancer. Our results show that there are palliative and curative options in the management of spinal metastasis, in the forms of radioiodine ablation, surgery, selective embolisation, bisphosphonates and more recently the VEGF receptor targets.

CONCLUSIONS

The management of spinal metastasis from thyroid cancer should be multi-disciplinary. There is an absence; it seems, of a definitive protocol for treatment. Research shows increased survival with 131I avidity and complete bone metastasis resection. Early detection and treatment therefore are crucial. Studies suggest in those patients below the age of 45 years that treatment should be aggressive, and aim for cure. In those patients in whom curative treatment is not an option, palliative treatments are available.

[Management of painful bone metastases]

Bone metastases are frequently symptomatic. The pain is specific due to its pathophysiology, characteristics and treatment. Conventional antalgic pain management may be insufficient and management should be multifacetted, global and multidisciplinary. Interventional radiology procedures widen the range of possible antalgic therapies. Their role in the management of patients should be defined by a multidisciplinary team on a case-by-case review, based on the patient's symptoms and fracture risk. Additional scientific validation of the effectiveness of such therapies is needed. Recommendations on the role of interventional radiology procedures in the management of patients with symptomatic bone metastases are needed to standardize the different practices and increase the role of interventional radiology in the management of symptomatic bone metastases at the national level. Implementation of the cancer 2009-2012 project could facilitate the availability of these therapies to patients with cancer pain.

Percutaneous magnetic resonance imaging-guided bone tumor management and magnetic resonance imaging-guided bone therapy

Magnetic resonance imaging (MRI) is promising tool for image-guided therapy. In musculoskeletal setting, image-guided therapy is used to direct diagnostic and therapeutic procedures and to steer patient management. Studies have demonstrated that MRI-guided interventions involving bone, soft tissue, joints, and intervertebral disks are safe and in selected indications can be the preferred action to manage clinical situation. Often, these procedures are technically similar to those performed in other modalities (computed tomography, fluoroscopy) for bone and soft tissue lesions. However, the procedural perception to the operator can be very different to other modalities because of the vastly increased data.Magnetic resonance imaging guidance is particularly advantageous should the lesion not be visible by other modalities, for selective lesion targeting, intra-articular locations, cyst aspiration, and locations adjacent to surgical hardware. Palliative tumor-related pain management such as ablation therapy forms a subset of procedures that are frequently performed under MRI. Another suitable entity for MRI guidance are the therapeutic percutaneous osseous or joint-related benign or reactive conditions such as osteoid osteoma, epiphyseal bone bridging, osteochondritis dissecans, bone cysts, localized bone necrosis, and posttraumatic lesions. In this article, we will describe in detail the technical aspects of performing MRI-guided therapeutic musculoskeletal procedures as well as the clinical indications.

Emerging therapies in metastatic bone pain

INTRODUCTION

Current treatment for metastatic bone pain is mainly palliative. Recent insights into the molecular mechanisms involved in bone metastases have led to the identification of promising therapeutic targets. This review offers an update of preclinical and clinical data on new drugs for metastatic bone pain.

AREAS COVERED

Biphosphonates are the gold standard of bone-targeted therapy in bone metastases, for their anti-resorptive and analgesic effects. New drugs aim at breaking the 'vicious cycle' of bone metastatic disease, due to the bidirectional interaction between cancer cells and bone microenvironment. Osteoprotegerin, RANK/RANKL interaction, cathepsin K, the Wnt/beta-catenin pathway and sclerostin are emerging targets for modulation of cancer-induced bone desorption. Other promising targets are those expressed in cancer cells that metastasize to bone, including Src, nerve growth factor, endothelin A, TGF-beta and CXCR4. Interesting therapeutic options include targets on nociceptors that innervate the bone, such as TPRV1, Trk and cannabinoid receptors.

EXPERT OPINION

Emerging therapies promise, in the next 10 years, a significant expansion in the array of therapeutic options for bone metastases. Most of these drugs are still in an early phase of development. Further clinical trials are needed to support the evidence of their efficacy and tolerability profile.

Anesthesia for patients undergoing orthopedic oncologic surgeries

When planning an anesthetic for patients undergoing orthopedic oncologic surgeries, numerous factors must be considered. Preoperative evaluation may elucidate significant co-morbidities or side effects secondary to chemotherapy or radiation, which can affect anesthetic choices. Procedures vary in length and complexity and pose challenges in both positioning and in planning to minimize blood loss. Many anesthetic techniques are available to provide both intraoperative anesthesia and postoperative analgesia, while the type of thromboprophylaxis and analgesic adjuvants that will be administered needs to be defined. This review focuses on approaches to use when caring for patients undergoing orthopedic oncologic procedures.

Additive inhibitory effects of calcitonin and capsaicin on voltage activated calcium channel currents in nociceptive neurones of rat

Calcitonin, a peptide hormone expressed in C-cells of the thyreoid gland, as well as capsaicin, isolated from chili, both, modify intracellular signalling in nociceptive neurones. The pathways triggered by the activation of either of these receptors results in a modulation of the intracellular calcium ([Ca(2+)](i)) concentration. While the regulation of [Ca(2+)](i) depends on many factors, voltage activated calcium channels (VACCs) are a major gate for the calcium entry into neurones. Here we describe the changes of voltage gated calcium channel currents (I(Ca(V))) induced by calcitonin and/or capsaicin. Currents were recorded using adequate solutions and voltage protocols with the whole cell patch-clamp technique. When the channels were opened by a depolarisation to 0 mV, both substances reduce the peak I(Ca(V)) (calcitonin (10nM): 29.3 ± 3.9%; capsaicin (0.5 μM): 41.1 ± 7.7%). While the effect of calcitonin was voltage dependent, capsaicin shifted the largest current to the more hyperpolarizing range (peak current from -10 to -20 mV). A subsequent co-application of either of the two substances (with a pre-application of either 3 min or 60 min) results in an additive reduction of the currents, and prevents the capsaicin-induced shift of the current-voltage relation. Therefore, we hypothesize, that the activation of either of the two receptors reduces I(Ca(V)) by different cellular binding sites of the channel protein triggering channel opening. These findings may be useful to understand cellular mechanisms of pain modulation and might help to find better treatments for neuropathic pain.

Antinociceptive effect of intrathecal cannabinoid receptor agonist WIN 55,212-2 in a rat bone tumor pain model

Bone tumor pain is a poorly controlled pain comprising background and severe pain on moving or weight-bearing postures that decreases the quality of life for cancer patients; thus, more effective analgesics are clearly needed. This study evaluated the efficacy of a cannabinoid (CB) receptor agonist (WIN 55,212-2) on bone tumor pain in the spinal cords of rats, and clarified the roles of the CB1 and CB2 receptors in WIN 55,212-2-induced antinociception at the spinal level. Bone tumor pain was induced by injecting MRMT-1 tumor cells (1×10(5)) into the right tibias of female Sprague-Dawley rats under sevoflurane anesthesia. Bone tumor development was monitored radiologically. Under sevoflurane anesthesia, a polyethylene catheter was inserted into the intrathecal space for drug administration. To assess pain, the withdrawal threshold was measured by applying a von Frey filament to the tumor cell inoculation site. The effect of intrathecal WIN 55,212-2 was investigated. Next, the WIN 55,212-2-mediated antinociception was reversed using CB1 (AM 251) and CB2 (AM 630) receptor antagonists. The intratibial injection of MRMT-1 tumor cells produced radiologically confirmed bone tumors. The paw withdrawal threshold decreased significantly (mechanical allodynia) with tumor development; however, intrathecal WIN 55,212-2 dose-dependently increased the withdrawal threshold. The antinociceptive effect of WIN 55,212-2 was reversed by both CB1 and CB2 receptor antagonists. Intrathecal WIN 55,212-2 reduced bone tumor-related pain behavior mediated via spinal CB1 and CB2 receptors. Therefore, spinal CB receptor agonists may be novel analgesics in the treatment of bone tumor pain.

Analgesic effect of intrathecal ginsenosides in a murine bone cancer pain

BACKGROUND

Bone cancer pain has a disruptive effect on the cancer patient's quality of life. Although ginsenosides have been used as traditional medicine in Eastern Medicine, the effect on bone cancer pain has not been thoroughly studied. The aim of this study was to determine whether ginsenosides may alter the bone cancer pain at the spinal level.

METHODS

NCTC 2472 tumor cells (2.5 × 10(5)) were injected into the femur of adult male C3H/HeJ mice to evoke bone tumor and bone cancer pain. To develop bone tumor, radiologic pictures were obtained. To assess pain, the withdrawal threshold was measured by applying a von Frey filament to the tumor cells inoculation site. The effect of intrathecal ginsenosides was investigated. Effect of ginsenosides (150, 500, 1,000 µg) was examined at 15, 30, 60, 90, 120 min after intrathecal delivery.

RESULTS

The intrafemoral injection of NCTC 2472 tumor cells induced a radiological bone tumor. The withdrawal threshold with tumor development was significantly decreased compared to the sham animals. Intrathecal ginsenosides effectively increased the withdrawal threshold in the bone cancer site.

CONCLUSIONS

NCTC 2472 tumor cells injection into the mice femur caused bone tumor and bone cancer pain. Intrathecal ginsenosides attenuated the bone cancer-related pain behavior. Therefore, spinal ginsenosides may be an alternative analgesic for treating bone cancer pain.

Behavioral, medical imaging and histopathological features of a new rat model of bone cancer pain

Pre-clinical bone cancer pain models mimicking the human condition are required to respond to clinical realities. Breast or prostate cancer patients coping with bone metastases experience intractable pain, which affects their quality of life. Advanced monitoring is thus required to clarify bone cancer pain mechanisms and refine treatments. In our model of rat femoral mammary carcinoma MRMT-1 cell implantation, pain onset and tumor growth were monitored for 21 days. The surgical procedure performed without arthrotomy allowed recording of incidental pain in free-moving rats. Along with the gradual development of mechanical allodynia and hyperalgesia, behavioral signs of ambulatory pain were detected at day 14 by using a dynamic weight-bearing apparatus. Osteopenia was revealed from day 14 concomitantly with disorganization of the trabecular architecture (µCT). Bone metastases were visualized as early as day 8 by MRI (T(1)-Gd-DTPA) before pain detection. PET (Na(18)F) co-registration revealed intra-osseous activity, as determined by anatomical superimposition over MRI in accordance with osteoclastic hyperactivity (TRAP staining). Pain and bone destruction were aggravated with time. Bone remodeling was accompanied by c-Fos (spinal) and ATF3 (DRG) neuronal activation, sustained by astrocyte (GFAP) and microglia (Iba1) reactivity in lumbar spinal cord. Our animal model demonstrates the importance of simultaneously recording pain and tumor progression and will allow us to better characterize therapeutic strategies in the future.

Intraperitoneal injection of thalidomide attenuates bone cancer pain and decreases spinal tumor necrosis factor-α expression in a mouse model

Background

Tumor necrosis factor α (TNF-α) may have a pivotal role in the genesis of mechanical allodynia and thermal hyperalgesia during inflammatory and neuropathic pain. Thalidomide has been shown to selectively inhibit TNF-α production. Previous studies have suggested that thalidomide exerts anti-nociceptive effects in various pain models, but its effects on bone cancer pain have not previously been studied. Therefore, in the present study, we investigated the effect of thalidomide on bone cancer-induced hyperalgesia and up-regulated expression of spinal TNF-α in a mouse model.

Results

Osteosarcoma NCTC 2472 cells were implanted into the intramedullary space of the right femurs of C3H/HeJ mice to induce ongoing bone cancer related pain behaviors. At day 5, 7, 10 and 14 after operation, the expression of TNF-α in the spinal cord was higher in tumor-bearing mice compared to the sham mice. Intraperitoneal injection of thalidomide (50 mg/kg), started at day 1 after surgery and once daily thereafter until day 7, attenuated bone cancer-evoked mechanical allodynia and thermal hyperalgesia as well as the up-regulation of TNF-α in the spinal cord.

Conclusions

These results suggest that thalidomide can efficiently alleviate bone cancer pain and it may be a useful alternative or adjunct therapy for bone cancer pain. Our data also suggest a role of spinal TNF-α in the development of bone cancer pain.

Spine metastases: current treatments and future directions

Spinal metastases are the most frequently encountered spinal tumour and can affect up to 50% of cancer patients. Both the incidence and prevalence of metastases are thought to be rising due to better detection and treatment options of the systemic malignancy resulting in increased patient survival. Further, the development and access to newer imaging modalities have resulted in easier screening and diagnosis of spine metastases. Current evidence suggests that pain, neurological symptoms and quality of life are all improved if patients with spine metastases are treated early and aggressively. However, selection of the appropriate therapy depends on several factors including primary histology, extent of the systemic disease, existing co-morbidities, prior treatment modalities, patient age and performance status, predicted life expectancy and available resources. This article reviews the currently available therapeutic options for spinal metastases including conventional external beam radiation therapy, open surgical decompression and stabilisation, vertebral augmentation and other minimally invasive surgery (MIS) options, stereotactic spine radiosurgery, bisphosphonates, systemic radioisotopes and chemotherapy. An algorithm for the management of spine metastases is also proposed. It outlines a multidisciplinary and integrated approach to these patients and it is hoped that this along with future advances and research will result in improved patient care and outcomes.

A cannabinoid 2 receptor agonist attenuates bone cancer-induced pain and bone loss

AIMS

Cannabinoid CB(2) agonists have been shown to alleviate behavioral signs of inflammatory and neuropathic pain in animal models. AM1241, a CB(2) agonist, does not demonstrate central nervous system side effects seen with CB(1) agonists such as hypothermia and catalepsy. Metastatic bone cancer causes severe pain in patients and is treated with analgesics such as opiates. Recent reports suggest that sustained opiates can produce paradoxical hyperalgesic actions and enhance bone destruction in a murine model of bone cancer. In contrast, CB(2) selective agonists have been shown to reduce bone loss associated with a model of osteoporosis. Here we tested whether a CB(2) agonist administered over a 7day period inhibits bone cancer-induced pain as well as attenuates cancer-induced bone degradation.

MAIN METHODS

A murine bone cancer model was used in which osteolytic sarcoma cells were injected into the intramedullary space of the distal end of the femur. Behavioral and radiographic image analysis was performed at days 7, 10 and 14 after injection of tumor cells into the femur.

KEY FINDINGS

Osteolytic sarcoma within the femur produced spontaneous and touch evoked behavioral signs of pain within the tumor-bearing limb. The systemic administration of AM1241 acutely or for 7days significantly attenuated spontaneous and evoked pain in the inoculated limb. Sustained AM1241 significantly reduced bone loss and decreased the incidence of cancer-induced bone fractures.

SIGNIFICANCE

These findings suggest a novel therapy for cancer-induced bone pain, bone loss and bone fracture while lacking many unwanted side effects seen with current treatments for bone cancer pain.

Involvement of the spinal NMDA receptor/PKCγ signaling pathway in the development of bone cancer pain

N-methyl-d-aspartate (NMDA) receptor and protein kinase C (PKC) play important roles in the induction and maintenance of central sensitization during pain states. It has been shown that spinal NMDA receptor-dependent activation of PKCgamma facilitates nociception during neuropathic and inflammatory pain, but its involvement in bone cancer pain has not previously been established. The aim of this study was to examine the potential role of the spinal NMDA receptor/PKCgamma signaling pathway in the development of bone cancer pain. Osteosarcoma NCTC 2472 cells were implanted into the intramedullary space of the right femurs of C3H/HeJ mice to induce ongoing bone cancer-related pain behaviors. At day 7, 10 and 14 after operation, the expression of PKCgamma mRNA in the spinal cord was higher in tumor-bearing mice compared to the sham mice. At day 14, intrathecal administration of 5 microg of NR2B subunit-specific NMDA receptor antagonist ifenprodil attenuated the up-regulation of PKCgamma mRNA in the spinal cord as well as bone cancer-evoked thermal hyperalgesia and mechanical allodynia. Furthermore, intrathecal injection of 10 microg of PKC inhibitor H-7 attenuated cancer-evoked thermal hyperalgesia and mechanical allodynia at day 14. These results suggest that the NMDA receptor/PKCgamma signaling pathway may participate in the development of bone cancer pain, and ifenprodil may be a useful alternative or adjunct therapy for bone cancer pain.

Patterns of pain and interference in patients with painful bone metastases: a brief pain inventory validation study

Bone metastases are prevalent, painful, and carry a poorer prognosis for pain control compared with other cancer pain syndromes. Standard tools to measure pain have not been validated in this patient population, and particular subgroups with more challenging symptoms have yet to be identified and studied. The objectives of this study were 1) to validate the psychometric properties of the Brief Pain Inventory (BPI) and its Pain and Interference subscales in patients with clinically significant metastatic bone pain requiring palliative radiotherapy and 2) to examine differences in BPI subscales among predefined subgroups of bone metastases patients. A total of 258 patients evaluated and treated through a rapid access radiation therapy clinic between July 2002, and November 2006, were included in the analysis. High internal consistency of the BPI subscales of Pain, Activity interference, and Affect interference was demonstrated by Cronbach's alpha between 0.81 and 0.89. Removing sleep interference improved model fit in confirmatory factor analysis. The BPI revealed an alarming pattern in patients with lower body metastases, who reported substantial interference of activity even though pain levels were mild or moderate. Such patients may require prompt clinical attention to better meet their needs. Finally, the allocation of interference from sleep within the BPI framework, in our population of pain patients, requires further study.

Multispecies animal investigation on biodistribution, pharmacokinetics and toxicity of 177Lu-EDTMP, a potential bone pain palliation agent

INTRODUCTION

Radionuclide therapy (RNT) is an effective method for bone pain palliation in patients suffering from bone metastasis. Due to the long half-life, easy production and relatively low beta- energy, (177)Lu [T(1/2)=6.73 days, E(beta max)=497 keV, E(gamma)=113 keV (6.4%), 208 keV (11%)]-based radiopharmaceuticals offer logistical advantage for wider use. This paper reports the results of a multispecies biodistribution and toxicity studies of (177)Lu-EDTMP to collect preclinical data for starting human clinical trials.

METHODS

(177)Lu-EDTMP with radiochemical purity greater than 99% was formulated by using a lyophilized kit of EDTMP (35 mg of EDTMP, 5.72 g of CaO and 14.1 mg of NaOH). Biodistribution studies were conducted in mice and rabbits. Small animal imaging was performed using NanoSPECT/CT (Mediso, Ltd., Hungary) and digital autoradiography. Gamma camera imaging was done in rabbits and dogs. Four levels of activity (9.25 through 37 MBq/kg body weight) of (177)Lu-EDTMP were injected in four groups of three dogs each to study the toxicological effects.

RESULTS

(177)Lu-EDTMP accumulated almost exclusively in the skeletal system (peak ca. 41% of the injected activity in bone with terminal elimination half-life of 2130 and 1870 h in mice and rabbits, respectively) with a peak uptake during 1-3 h. Excretion of the radiopharmaceutical was through the urinary system. Imaging studies showed that all species (mouse, rat, rabbit and dog) take up the compound in regions of remodeling bone, while kidney retention is not visible after 1 day postinjection (pi). In dogs, the highest applied activity (37 MBq/kg body weight) led to a moderate decrease in platelet concentration (mean, 160 g/L) at 1 week pi with no toxicity.

CONCLUSION

The protracted effective half-life of (177)Lu-EDTMP in bone supports that modifying the EDTMP molecule by introducing (177)Lu does not alter its biological behaviour as a specific bone-seeking tracer. Species-specific pharmacokinetic behavior differences were observed. Toxicity studies in dogs did not show any biological adverse effects. The studies demonstrate that (177)Lu-EDTMP is a promising radiopharmaceutical that can be further evaluated for establishing as a radiopharmaceutical for human use.

Clinical outcomes after percutaneous vertebroplasty for pathologic compression fractures in osteolytic metastatic spinal disease

OBJECTIVE

Percutaneous vertebroplasty (VP) can provide immediate stabilization in pathologic fractures of spinal tumors. However, long term follow-up data in cases of pathologic fractures are lacking. The authors report follow-up results of VP in 185 pathologic fractures of 102 spinal tumor patients.

METHODS

Percutaneous VP was performed at 185 vertebral bodies of 102 patients from 2001 to 2007. Retrospective analysis was done with medical records and radiological data. The change of visual analogue score (VAS), vertebral body (VB) height and kyphotic angle were measured preoperatively and on postoperative one day and at 3, 6, and 12 months.

RESULTS

The patients were composed of metastatic spine tumors (81%) and multiple myeloma (19%). Involved spinal segments were between T6 and L5. Mean follow-up period was 12.2 months. VAS for back pain was 8.24 preoperatively, 3.59 (postoperative one day), 4.08 (three months) and 5.22 (one year). VB compression ratio changed from 21.33% preoperatively to 13.82% (postoperative one day), 14.36% (three month), and 16.04% (one year). Kyphotic angle changed from 15.35 degrees preoperatively to 12.03 degrees (postoperative one day), 13.64 degrees (three month), and 15.61 degrees (one year).

CONCLUSION

Immediate pain relief was definite after VP in pathologic compression fracture of osteolytic spinal disease. Although VAS was slightly increased on one year follow-up, VP effect was maintained without significant change. These results indicate that VP could be a safe and effective procedure as a palliative treatment of the spinal tumor patients.