Causes and treatment of bone pain of malignant origin

Defining Spine Cancer Pain Syndromes: A Systematic Review and Proposed Terminology

STUDY DESIGN

Systematic Review.

OBJECTIVES

Formalized terminology for pain experienced by spine cancer patients is lacking. The common descriptors of spine cancer pain as mechanical or non-mechanical is not exhaustive. Misdiagnosed spinal pain may lead to ineffective treatment recommendations for cancer patients.

METHODS

We conducted a systematic review of pain terminology that may be relevant to spinal oncology patients. We provide a comprehensive and unbiased summary of the existing evidence, not limited to the spine surgery literature, and subsequently consolidate these data into a practical, clinically relevant nomenclature for spine oncologists.

RESULTS

Our literature search identified 3515 unique citations. Through title and abstract screening, 3407 citations were excluded, resulting in 54 full-text citations for review. Pain in cancer patients is typically described as nociceptive pain (somatic vs visceral), neurologic pain and treatment related pain.

CONCLUSIONS

We consolidate the terminology used in the literature and consolidated into clinically relevant nomenclature of biologic tumor pain, mechanical pain, radicular pain, neuropathic pain, and treatment related pain. This review helps standardize terminology for cancer-related pain which may help clinicians identify pain generators.

Effectiveness of advanced nursing care (ANC) on bone cancer pain, psychological disorders and quality of life in patients with primary bone cancers: A protocol for a PRISMA-compliant meta-analysis

BACKGROUND

Advanced nursing care (ANC) has been reported to effectively relieve bone cancer pain, prevent psychological disorders and improve the quality of life (QoL) in patients with primary bone cancers (PBC) during the treatment. However, the exact effect of ANC remains controversial. This systematic review will aimed to assess the effectiveness of ANC on bone cancer pain, psychological disorders and QoL in patients with PBC.

METHODS

Eligible randomized controlled trials (RCTs) and high-quality prospective cohort studies were searched from Excerpt Medica Database (Embase), PubMed, Google Scholar, Medline, Cochrane Library, Web of Science (WOS), China National Knowledge Infrastructure (CNKI), Chinese Bio Medical Database (CBM), China Scientific Journal Database (CSJD), and Wanfang Database. Papers in English or Chinese published from January 2000 to July 2020 will be included without any restrictions. The clinical outcomes including bone cancer pain, psychological disorders, QoL, and adverse events of ANC in patients with PBC were systematically evaluated.Two reviewers will separately carry out study selection and data extraction. Stata 14.0 and Review Manager 5.3 were used for data analysis. Methodological quality for each eligible clinical trial will be assessed by using Cochrane risk of bias tool. Subgroup and meta-regression analysis will be carried out depending on the availability of sufficient data.

RESULTS

This study will comprehensively summarize all potential evidence to systematically investigate the effects and safety of ANC on bone cancer pain, psychological disorders and QoL in patients with PBC.

CONCLUSION

The findings of this study will help to determine whether ANC is effective or not on bone cancer pain, psychological disorders and QoL in patients with PBC.

INPLASY REGISTRATION NUMBER

INPLASY202090037.

Mitochondrial genome of a multiple myeloma bone cancer disease model rat strain (Muridae; Rattus)

We sequenced the complete mitochondrial genome sequencing of a multiple myeloma bone cancer disease model rat strain for the first time. The total length of the mitogenome was 16,302 bp and coding 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes.

Comparison of single versus multiple fractions for palliative treatment of painful bone metastasis: first study from north west India

Background:

Bone metastasis is a usual cause of pain in advanced cancer. Conventional radiation schedules require larger hospital stay and thus are not suitable for patients with poor general condition. This prospective observational study aims to compare the pain-relieving efficacy of different radiation fractionation schedules, i.e., 8 Gy administered in a single fraction versus 30 Gy administered in 10 fractions.

Materials and Methods:

Two hundred and fifty consecutive patients of bone metastasis were evaluated for the study, with 63 patients being excluded due to non-fulfillment of the inclusion criteria. The response to radiotherapy leading to pain relief as per the Visual Analog Scale was recorded at the end of treatment, 8 days, 15 days and 1 month during the follow-up visits.

Results:

Sixty-two percent of the patients received a single fraction while the remaining received 10 fractions. In the 10-fraction group, overall response was present in 60% of the patients. Stable pain was present in 23% of the patients while 9% patients had progressive pain. At 1 month of completion of treatment, 9% patients were lost to follow-up. In the single-fraction arm, overall response was seen in 58%, stable pain in 27% and progressive pain in 7% of the patients. Six percent of the patients were lost to follow-up.

Conclusions:

Single-fraction treatment for bony metastasis is as effective as multiple fractions to relieve bony pain and provides treatment convenience to both the patient and the caregiver.

Hypalgesia effect of IL-24, a quite new mechanism for IL-24 application in cancer treatment

Tumor suppressor melanoma differentiation-associated gene-7/interleukin-24 (mda-7/IL-24) has been extensively regarded as an anti-oncogene; however, that whether IL-24, as a member of IL-10 family, is involved in cancer pain was seldom reported before. In this study, we found that IL-24 mediated by adenovirus could significantly increase the plantar mechanical pain threshold in both operation side and contralateral side of the animal models, which were established by injecting 5×103 Walker 256 rat breast cancer ascitic tumor cells into rats' tibia bone medullary canals; IL-24 could also suppress in vitro Walker 256 cells growth by inducing cell apoptosis. Pathologically, IL-24 could protect bone trabecula and substantia corticalis ossium from being completely destructed. Enzyme-linked immunosorbent assay (ELISA) showed that IL-24 treatment could increase the β-endorphin levels and decrease the IL-6 concentration in plasma of animals. Our study indicated that IL-24 has a potential treatment effect on cancers not only by inhibiting tumor proliferation, but also by the promotion of β-endorphin synthesis, inhibition of IL-6 secretion to relieve cancer pain.

Involvement of lysophosphatidic acid in bone cancer pain by potentiation of TRPV1 via PKCε pathway in dorsal root ganglion neurons

Background

It has been demonstrated that lysophosphatidic acid (LPA) released from injury tissue and transient receptor potential vanilloid 1 (TRPV1) receptor are implicated in the induction of chronic pain. In the present study we examined whether an interaction between LPA receptor LPA₁ and TRPV1 in dorsal root ganglion (DRG) neurons contributes to the development of bone cancer pain.

Results

Bone cancer was established by injection of mammary gland carcinoma cells into the rat tibia. Following the development of bone cancer pain, the TRPV1 expression and capsaicin-evoked currents were up-regulated in rat DRG neurons at L_4-6 segments. Immunohistochemistry staining revealed a high co-localization of LPA₁ with TRPV1 in DRG neurons. In isolated DRG neurons, whole-cell patch recording showed that capsaicin-induced currents were potentiated by LPA in a dose-dependent manner. The potentiation was blocked by either LPA₁ antagonist, protein kinase C (PKC) inhibitor or PKCϵ inhibitor, but not by protein kinase A (PKA) inhibitor or Rho inhibitor. In the behavioral tests, both mechanical allodynia and thermal hyperalgesia in bone cancer rats were attenuated by LPA₁ antagonist.

Conclusion

LPA potentiates TRPV1 current via a PKCϵ-dependent pathway in DRG neurons of rats with bone cancer, which may be a novel peripheral mechanism underlying the induction of bone cancer pain.

Structural pathology in a rodent model of osteoarthritis is associated with neuropathic pain: increased expression of ATF-3 and pharmacological characterisation

Intra-articular injection of mono-iodoacetate (MIA) in the rat knee joint induces a histopathology with similarities to osteoarthritis (OA). Typically, a synovitis (days 1-3) is observed followed by thinning of articular cartilage and subsequent lesion of subchondral bone at days 8-14 onwards. Behaviourally, weight-bearing asymmetry is observed, which is sensitive to anti-inflammatory pharmacology at early but not later (days 14+) time points. As subchondral bone is densely innervated, an intriguing possibility is that focal bone pathology may cause neuropathy in this model. In male Wistar rats, activating transcription factor (ATF)-3-immunofluorescence was used as a marker of nerve injury in lumber (L)4 and L5 dorsal root ganglia of the ipsilateral knee. Significantly increased ATF-3-immunoreactivity following MIA treatment was measured in L5 on days 8 and 14 (P<0.05, Kruskal-Wallis and Mann-Whitney U-test), compared to saline controls. Furthermore, in an additional study animals were orally dosed vehicle (5 ml/kg), naproxen (0.3-10 mg/kg), celecoxib (1-10 mg/kg), amitriptyline (3-30 mg/kg) and gabapentin (10-100mg/kg) and evaluated for weight-bearing asymmetry on days 14, 21 and 28 post-MIA. Significant resolution of weight-bearing was observed at high and intermediate doses of amitriptyline and gabapentin at all time points (P<0.05, ANOVA, post-hoc Bonferroni's, vs pre-dose measurements). Transient and weak effects were observed with naproxen (10mg/kg) on days 14 and 28, whereas celecoxib showed no significant effects. Collectively, these data suggest that this putative model of OA is associated with an early phase neuropathy in the L5 innervation territory of the knee.

Evaluation of pain-related behavior, bone destruction and effectiveness of fentanyl, sufentanil, and morphine in a murine model of cancer pain

The present study was conducted to evaluate the pain development and bone destruction during bone cancer growth in a murine model of bone cancer pain and to evaluate the analgesic efficacy of fentanyl, sufentanil, and morphine in this model. C3H/HeNCrl mice were inoculated into the intramedullary space of the femur with osteolytic NCTC 2472 fibrosarcoma cells, and followed during a 3-week period to assess pain behaviors (spontaneous lifting and limb-use during forced ambulation on rotarod) and bone destruction (parameters indicative of bone lesions determined by microCT-scans of the tumor-bearing bones) during bone cancer growth. The results showed that in this murine model of cancer-induced bone pain, behavioural manifestations of pain emerge in parallel with the progression of bone destruction. The subcutaneous administration of fentanyl (0.025-0.64 mg/kg), sufentanil (0.005-0.04 mg/kg), and morphine (2.5-40 mg/kg) on the test days 15 and 22 post-inoculation reduced pain-related behaviors in a dose dependent manner. A complete relief from pain-related behaviors was achieved with the following doses: > or =0.16 mg/kg fentanyl, 0.02 mg/kg sufentanil, and 20 mg/kg morphine. In conclusion, the results showed a clear link between tumor growth-induced bone destruction and behavioral pain manifestations, the latter was effectively controlled by the opioids fentanyl, sufentanil, and morphine.

Randomized Clinical Trial of the Effectiveness of a Self-Care Intervention to Improve Cancer Pain Management

Purpose

This randomized clinical trial tested the effectiveness of the PRO-SELF Pain Control Program compared with standard care in decreasing pain intensity scores, increasing appropriate analgesic prescriptions, and increasing analgesic intake in oncology outpatients with pain from bone metastasis.

Patients and Methods

Patients were randomly assigned to the PRO-SELF intervention (n = 93) or standard care (n = 81). Patients in the standard care arm were seen by a research nurse three times and were called three times by phone between the home visits. PRO-SELF group patients were seen by specially trained intervention nurses and received a psychoeducational intervention, were taught how to use a pillbox, and were given written instructions on how to communicate with their physician about unrelieved pain and the need for changes in their analgesic prescriptions. Patients were coached during two follow-up home visits and three phone calls on how to improve their cancer pain management.

Results

Pain intensity scores decreased significantly from baseline (all P < .0001) in the PRO-SELF group (ie, least pain, 28.4%; average pain, 32.5%; and worst pain, 27.0%) compared with the standard care group (ie, least increased by 14.6%, average increased by 1.9%, and worst decreased by 1.2%). The percentage of patients in the PRO-SELF group with the most appropriate type of analgesic prescription increased significantly from 28.3% to 37.0% (P = .008) compared with a change from 29.6% to 32.5% in the standard care group.

Conclusion

The use of a psychoeducational intervention that incorporates nurse coaching within the framework of self-care can improve the management of cancer pain.

Endothelin and the tumorigenic component of bone cancer pain

Tumors including sarcomas and breast, prostate, and lung carcinomas frequently grow in or metastasize to the skeleton where they can induce significant bone remodeling and cancer pain. To define products that are released from tumors that are involved in the generation and maintenance of bone cancer pain, we focus here on endothelin-1 (ET-1) and endothelin receptors as several tumors including human prostate and breast have been shown to express high levels of ETs and the application of ETs to peripheral nerves can induce pain. Here we show that in a murine osteolytic 2472 sarcoma model of bone cancer pain, the 2472 sarcoma cells express high levels of ET-1, but express low or undetectable levels of endothelin A (ETAR) or B (ETBR) receptors whereas a subpopulation of sensory neurons express the ETAR and non-myelinating Schwann cells express the ETBR. Acute (10 mg/kg, i.p.) or chronic (10 mg/kg/day, p.o.) administration of the ETAR selective antagonist ABT-627 significantly attenuated ongoing and movement-evoked bone cancer pain and chronic administration of ABT-627 reduced several neurochemical indices of peripheral and central sensitization without influencing tumor growth or bone destruction. In contrast, acute treatment (30 mg/kg, i.p.) with the ETBR selective antagonist, A-192621 increased several measures of ongoing and movement evoked pain. As tumor expression and release of ET-1 has been shown to be regulated by the local environment, location specific expression and release of ET-1 by tumor cells may provide insight into the mechanisms that underlie the heterogeneity of bone cancer pain that is frequently observed in humans with multiple skeletal metastases.

Anti-hyperalgesic activity of the cox-2 inhibitor lumiracoxib in a model of bone cancer pain in the rat

Chronic pain resulting from metastatic bone cancer remains poorly understood and resistant to treatment. Here we have examined the effect of the novel COX-2 enzyme inhibitor lumiracoxib in a model of bone cancer pain in the rat. Lumiracoxib was administered orally twice daily from day 10 to day 20 after injection of MRMT-1 tumour cells into one tibia. Mechanical hyperalgesia, measured as the reduction in weight-bearing of the ipsilateral limb, and the development of static and dynamic allodynia were significantly inhibited by repeated lumaricoxib administration. A similar reduction in hyperalgesia and allodynia was noted after twice daily administration of another COX-2 inhibitor, valdecoxib, whilst a single acute administration of either drug on day 20, produced no anti-nociceptive activity. Bone mineral density measurements, radiological scores and histological analysis showed that chronic lumaricoxib treatment also significantly attenuated bone destruction induced by tumour cell injection. These data indicate that lumiracoxib and other COX-2 inhibitors have potential therapeutic benefit in the treatment of bone cancer pain.

Double-blind evaluation of short-term analgesic efficacy of orally administered dexketoprofen trometamol and ketorolac in bone cancer pain

The analgesic efficacy and safety of dexketoprofen trometamol (the active enantiomer of the racemic compound ketoprofen) (25mg q.i.d.) vs. ketorolac (10mg q.i.d.) was assessed in 115 patients with bone cancer pain included in a multicenter, randomized, double-blind, parallel group study. A level of >/=40 mm on the 100 mm visual analog scale (VAS) and >/=10 in the pain rating index were required for inclusion. At the end of treatment on day 7 (+1 day), mean values of VAS were 32+/-24 mm for dexketoprofen and 40+/-30 mm for ketorolac (P=0.12) but the pain rating index was significantly lower in patients given dexketoprofen (8.5+/-2.3 vs. 9.7+/-2.9, P=0.04). Moreover, most of the patients reached a pain intensity difference from baseline >/=20 mm (75% of patients for dexketoprofen and 65% of patients for ketorolac). Around half of patients in both treatments had a pain intensity <30 mm on VAS at the end of treatment (55% for dexketoprofen and 47% for ketorolac). In the overall assessment of efficacy, a higher percentage of both patients and physicians rated dexketoprofen as 'quite effective' or 'very effective' compared to ketorolac. The percentage of patients withdrawn from the study for any reason as well as for insufficient therapeutic effect or due to adverse events was lower in the dexketoprofen group than in the ketorolac group. Treatment-related adverse events occurred in 16% of patients given dexketoprofen and in 24% given ketorolac. Serious adverse events occurred in 3.5% of patients from both groups but only one case of gastrointestinal hemorrhage was considered related to ketorolac. We conclude that dexketoprofen trometamol 25 mg q.i.d. oral route is a good analgesic therapy in the treatment of bone cancer pain, comparable to ketorolac 10 mg q.i.d., with a good tolerability profile.

Different tumors in bone each give rise to a distinct pattern of skeletal destruction, bone cancer-related pain behaviors and neurochemical changes in the central nervous system

Pain is the most common presenting symptom in patients with bone cancer and bone cancer pain can be both debilitating and difficult to control fully. To begin to understand the mechanisms involved in the generation and maintenance of bone cancer pain, we implanted 3 well-described murine tumor cell lines, 2472 sarcoma, B16 melanoma and C26 colon adenocarcinoma into the femur of immunocompromised C3H-SCID mice. Although each of the tumor cell lines proliferated and completely filled the intramedullary space of the femur within 3 weeks, the location and extent of bone destruction, the type and severity of the pain behaviors and the neurochemical reorganization of the spinal cord was unique to each tumor cell line injected. These data suggest that bone cancer pain is not caused by a single factor such as increased pressure induced by intramedullary tumor growth, but rather that multiple factors are involved in generating and maintaining bone cancer pain.

Disease modifying and anti-nociceptive effects of the bisphosphonate, zoledronic acid in a model of bone cancer pain

Inoculation of syngeneic MRMT-1 mammary tumour cells into one tibia of female rats produced tumour growth within the bone associated with a reduction in bone mineral density (BMD) and bone mineral content (BMC), severe radiological signs of bone destruction, together with the development of behavioural mechanical allodynia and hyperalgesia. Histological and radiological examination showed that chronic treatment with the bisphosphonate, zoledronic acid (30 microg/kg, s.c.), for 19 days significantly inhibited tumour proliferation and preserved the cortical and trabecular bone structure. In addition, BMD and BMC were preserved and a dramatic reduction of tartrate resistant acid phosphatase-positive polykaryocytes (osteoclasts) was observed. In behavioural tests, chronic treatment with zoledronic acid but not the significantly less effective bisphosphonate, pamidronate, or the selective COX-2 inhibitor, celebrex, attenuated mechanical allodynia and hyperalgesia in the affected hind paw. Zoledronic acid also attenuated mechanical hyperalgesia associated with chronic peripheral neuropathy and inflammation in the rat. In contrast, pamidronate or clodronate did not have any anti-hyperalgesic effect on mechanical hyperalgesia in the neuropathic and inflammatory pain models. We conclude that zoledronic acid, in addition to, or independent from, its anti-metastatic and bone preserving therapeutic effects, is an anti-nociceptive agent in a rat model of metastatic cancer pain. This unique property of zoledronic acid amongst the bisphosphonate class of compounds could make this drug a preferred choice for the treatment of painful bone metastases in the clinic.

Origins of skeletal pain: sensory and sympathetic innervation of the mouse femur

Although skeletal pain plays a major role in reducing the quality of life in patients suffering from osteoarthritis, Paget's disease, sickle cell anemia and bone cancer, little is known about the mechanisms that generate and maintain this pain. To define the peripheral fibers involved in transmitting and modulating skeletal pain, we used immunohistochemistry with antigen retrieval, confocal microscopy and three-dimensional image reconstruction of the bone to examine the sensory and sympathetic innervation of mineralized bone, bone marrow and periosteum of the normal mouse femur. Thinly myelinated and unmyelinated peptidergic sensory fibers were labeled with antibodies raised against calcitonin gene-related peptide (CGRP) and the unmyelinated, non-peptidergic sensory fibers were labeled with the isolectin B4 (Bandeira simplicifolia). Myelinated sensory fibers were labeled with an antibody raised against 200-kDa neurofilament H (clone RT-97). Sympathetic fibers were labeled with an antibody raised against tyrosine hydroxylase. CGRP, RT-97, and tyrosine hydroxylase immunoreactive fibers, but not isolectin B4 positive fibers, were present throughout the bone marrow, mineralized bone and the periosteum. While the periosteum is the most densely innervated tissue, when the total volume of each tissue is considered, the bone marrow receives the greatest total number of sensory and sympathetic fibers followed by mineralized bone and then periosteum. Understanding the sensory and sympathetic innervation of bone should provide a better understanding of the mechanisms that drive bone pain and aid in developing therapeutic strategies for treating skeletal pain.

A rat model of bone cancer pain

This study describes the first known model of bone cancer pain in the rat. Sprague-Dawley rats receiving intra-tibial injections of syngeneic MRMT-1 rat mammary gland carcinoma cells developed behavioural signs indicative of pain, including: mechanical allodynia, difference of weight bearing between hind paws and mechanical hyperalgesia. The development of the bone tumour and structural damage to the bone was monitored by radiological analysis, quantitative measurement of mineral content and histology. Intra-tibial injections of 3 x 10(3) or 3 x 10(4) syngeneic MRMT-1 cells produced a rapidly expanding tumour within the boundaries of the tibia, causing severe remodelling of the bone. Radiographs showed extensive damage to the cortical bone and the trabeculae by day 10-14 after inoculation of 3 x 10(3) MRMT-1 cells, and by day 20, the damage was threatening the integrity of the tibial bone. While both mineral content and mineral density decreased significantly in the cancerous bone, osteoclast numbers in the peritumoural compact bone remained unchanged. However, tartarate-resistant acid phosphatase staining revealed a large number of polykariotic cells, resembling those of osteoclasts within the tumour. No tumour growth was observed after the injection of heat-killed MRMT-1 cells. Intra-tibial injections of 3 x 10(3) or 3 x 10(4) MRMT-1 cells, heat-killed cells or vehicle did not show changes in body weight and core temperature over 19-20 days. The general activity of animals after injection with live or heat-killed MRMT-1 cells was higher than that of the control group, however, the activity of the MRMT-1 treated group declined during the progress of the disease. Rats receiving intra-tibial injections of MRMT-1 cells displayed the gradual development of mechanical allodynia and mechanical hyperalgesia/reduced weight bearing on the affected limb, beginning on day 12-14 or 10-12 following injection of 3 x 10(3) or 3 x 10(4) cells, respectively. These symptoms were not observed in rats receiving heat-killed cells or vehicle. Behavioural data suggest a reasonable time window for evaluation of anti-nociceptive agents between day 14 and 20 after cancer cell inoculation in this model. Acute treatment with morphine (1-3mg/kg, subcutanously (s.c.)) produced a dose-dependent reduction in the response frequency of hind paw withdrawal to von Frey filament stimulation 17 or 19 days following intra-tibial injections of 3 x 10(3) MRMT-1 cells. A significant reduction in the difference in hind limb weight bearing was also observed. Acute treatment with celebrex (10-30 mg/kg, s.c.) did not affect mechanical allodynia or difference in weight bearing in rats 20 days following treatment with 3 x 10(3) MRMT-1 cells. Although the pathophysiology of cancer pain is largely unknown, significant enhancement of glial fibrillary acidic protein (GFAP) staining in the corresponding segments of the ipsilateral spinal cord highlights the possible involvement of astrocytes. In summary, the induction of bone cancer in the rat by the syngeneic MRMT-1 mammary tumour cell line provides a valid pre-clinical model for pain associated with bone metastases. Significant mechanical hyperalgesia and allodynia develops in association with the progression of the tumour in the bone marrow cavity, while the general condition of the animal remains satisfactory. While acute treatment with morphine has some analgesic effect on hind limb sparing the selective COX-2 inhibitor, celebrex, has no influence on the pain-related behavioural changes in this model.

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.

Influence of antineoplastic drugs on morphine analgesia and on morphine tolerance

The possible influence of cisplatin, methotrexate, adriamycin and vincristine on thermal pain threshold, morphine analgesia and development of morphine tolerance was investigated in mice. In the hot-plate test, the nociceptive threshold was not affected by acute or repeated administration of any of the antineoplastic drugs used. The analgesic activity of morphine was significantly reduced by pretreatment with cisplatin, intraperitoneally (i.p.) injected at the dose of 2 mg/kg. In contrast, methotrexate, subcutaneously (s.c.) injected at the dose of 1 and 5 mg/kg, adriamycin (1 and 3 mg/kg s.c.), vincristine (0.25 and 0.5 mg/kg i.p.) and a lower dose of cisplatin (1 mg/kg i.p.) had no effect. The development of tolerance to morphine analgesia was delayed by adriamycin but was not influenced by the other antineoplastic drugs used. These data show that, of the four antineoplastic agents used in this study, cisplatin may interfere in the mechanism of action of morphine, and that adriamycin may delay the development of opiate tolerance.

Reactor-produced radioisotopes from ORNL for bone pain palliation

The treatment of painful skeletal metastases is a common clinical problem, and the use of therapeutic radionuclides which localize at metastatic sites has been found to be an effective method for treatment of pain, especially for multiple sites for which the use of external beam irradiation is impractical. There are currently several metastatic-targeted agents radiolabeled with various therapeutic radionuclides which are in various stages of clinical investigation. Since neutron-rich radionuclides are produced in research reactors and often decay by emission of beta- particles, most radionuclides used for bone pain palliation are reactor-produced. Key examples of radionuclides produced by single neutron capture of enriched targets include rhenium-186 and samarium-153. In addition, generator systems are also of interest which provide therapeutic daughter radionuclides from the decay of reactor-produced parent radionuclides. One important example is rhenium-188, available from generators via decay of reactor-produced tungsten-188. Tin-117m is an example of a reactor-produced radionuclide which decays with the emission of low-energy conversion electrons rather than by beta- decay. Each of these agents and/or radionuclides has specific advantages and disadvantages, however, the ideal agent for bone pain palliation has not yet been identified. The goal of this paper is to briefly review the production and use of several reactor-produced radionuclides for bone pain palliation, and to discuss the role of the ORNL High Flux Isotope Reactor (HFIR) for the production of many of these radionuclides.