The management of intractable bone pain: a clinician's perspective

The Role of procollagen type 1 amino-terminal propertied (P1NP) Cytochrome P450 (CYPs) and Osteoprotegerin (OPG) as Potential Bone function markers in Prostate Cancer Bone Metastasis

Background: Procollagen type I amino-terminal propeptide (PINP) is often present during osteoblast development and could be a biomarker of early bone development. Osteoprotegerin (OPG) may protect tumor cells from apoptosis. Cytochrome P450 enzymes help tumor development and treatment (CYPs). Cytochrome P450 activates and deactivates anticancer drugs and procarcinogens.

Objective: The study examined the amounts of a diagnostic marker of bone formation, the amino terminal propeptide of type I procollagen (PINP), Osteoprotegerin (OPG), and P450, in prostate cancer patients at different stages and its ability to detect osteoblastic metastases.

Methods: ELISA was used to measure PINP, OPG, and P450 levels in 30 prostate cancer patients. (n = 32) and healthy men’s serum (n = 36).

Results: Prostate cancer patients had higher blood levels of PINP, OPG, and P450 than healthy persons (301.3±134.9, 980±467.2, and 84.2±28.4 pg/mL, respectively). Compared to I+II prostate cancer patients, III+IV patients showed higher serum PINP, OPG, and P450 levels (P 0.001). OPG, P450, and PINP had statistically significant Area under the ROC curve (0.9467, P= 0.0001, 0.91, P= 0.0001, and 0.6977, P= 0.4035) in prostate cancer patients.

Conclusions: Metastatic prostate cancer patients had greater PINP, OPG, and P450 levels, according to our findings. PINP, OPG, and P450 levels may affect prostate cancer progression. These findings imply that serum PINP, OPG, and P450 levels may predict and diagnose prostate cancer.

Feasibility study for production and quality control of Yb-175 as a byproduct of no carrier added Lu-177 preparation for radiolabeling of DOTMP

Skeletal uptake of β^- emitters of DOTMP complexes is used for the bone pain palliation. In this study, two moderate energy β^- emitters, ¹⁷⁷Lu (T_1/2 = 6.7 days, E_βmax = 497 keV) and ¹⁷⁵Yb (T_1/2 = 4.2 days, E_βmax = 480 keV), are considered as potential agents for the development of the bone-seeking radiopharmaceuticals. Since the specific activity of the radiolabelled carrier molecules should be high, the non-carrier-added (NCA) radionuclides have an effective role in nuclear medicine. Many researchers have presented the synthesis of NCA ¹⁷⁷Lu. Among these separation techniques, extraction chromatography has been considered more capable than other methods. In this study, a new approach, in addition to production of NCA ¹⁷⁷Lu by EXC procedure is using pure ¹⁷⁵Yb that was usually considered as a waste material in this method but because of high radionuclidic purity of ¹⁷⁵Yb produced by this method we used it for radiolabeling as well as NCA ¹⁷⁷Lu. To obtain optimum conditions, some effective factors on separation of Lu/Yb by EXC were investigated. The NCA ¹⁷⁷Lu and pure ¹⁷⁵Yb were produced with radionuclidic purity of 99.99 and 99.97% respectively by irradiation of enriched ¹⁷⁶Yb target in thermal neutron flux of 5 × 10¹³ n/cm² s for 14 days. ¹⁷⁷Lu-DOTMP and ¹⁷⁵Yb-DOTMP were obtained with high radiochemical purities (> 95%) under optimized reaction conditions. Two radiolabeled complexes exhibited excellent stability at room temperature. Biodistribution studies in rats showed favorable selective skeletal uptake with rapid clearance from blood along with insignificant accumulation of activity in other non-target organs for two radiolabelled complexes.

Production and quality control 177Lu (NCA)-DOTMP as a potential agent for bone pain palliation

Skeletal uptake of radiolabeled-1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetramethylene phosphoric acid (e.g., 177Lu-DOTMP) complex, is used for bone pain palliation. The moderate energy of β-emitting 177Lu (T½ = 6.7 d, Eβmax = 497keV) has been considered as a potential radionuclide for development of the bone-seeking radiopharmaceutical. Since the specific activity of the radiolabeled carrier molecules should be high, the "no-carrier-added radionuclides" have sig-nificant roles in nuclear medicine. Many researchers illustrated no-carrier-added 177Lu production; among these separation techniques such as ion exchange chromatography, reversed phase ion-pair, and electrochemical method, extraction chromatography has been considered more capable than other methods. In order to optimize the conditions, some effective factors on separation of Lu/Yb were investigated by EXC. The NCA 177Lu, produced by this method, was mixed with 300 μl of DOTMP solution (20 mg in 1 mL of 0.5 M NaHCO3, pH = 8) and incu-bated under stirring at room temperature for 45 min. Radiochemical purity of the 177Lu-DOTMP complex was determined using radio-thin-layer chromatography (RTLC) method. The complex was injected to wild-type rats and biodistribution was then studied for seven days. The NCA 177Lu was produced with specific activ-ity of 48 Ci/mg and with a radinuclidic purity of 99.99% through irradiation of enriched 176Yb target (1 mg) in a thermal neutron flux of 4 × 1013 n.cm-2.s-1 for 14 days. 177Lu-DOTMP was obtained with high radiochemical purities (> 98%) under optimized reaction conditions. The radiolabeled complex exhibited excellent stability at room temperature. Biodistribution of the radiolabeled complex studies in rats showed favorable selective skeletal uptake with rapid clearance from blood along with insignificant accumulation within the other nontargeted organs.

Study of Bone Surface Absorbed Dose in Treatment of Bone Metastases via Selected Radiopharmaceuticals: Using MCNP4C Code and Available Experimental Data

Bone metastases are major clinical concern that can cause severe problems for patients. Currently, various beta emitters are used for bone pain palliation. This study, describes the process for absorbed dose prediction of selected bone surface and volume-seeking beta emitter radiopharmaceuticals such as (32)P, (89)SrCl2,(90)Y-EDTMP,(153)Sm-EDTMP, (166)Ho-DOTMP, (177)Lu-EDTMP,(186)Re-HEDP, and (188)Re-HEDP in human bone, using MCNP code. Three coaxial sub-cylinders 5 cm in height and 1.2, 2.6, and 7.6 cm in diameter were used for bone marrow, bone, and muscle simulation respectively. The *F8 tally was employed to calculate absorbed dose in the MCNP4C simulations. Results show that with injection of 1 MBq of these radiopharmaceuticals given to a 70 kg adult man, (32)P, (89)SrCl2, and (90)Y-EDTMP radiopharmaceuticals will have the highest amount of bone surface absorbed dose, where beta particles will have the greatest proportion in absorbed dose of bone surface in comparison with gamma radiation. These results demonstrate moderate agreement with available experimental data.

Development of (166)Holmium-1,2 Propylene Di-amino Tetra (Methy1enephosphonicacid) as a Possible Bone Palliation Agent

¹⁶⁶Holmium-1,2-propylene di-amino tetra (methy1enephosphonicacid) (¹⁶⁶ Ho-PDTMP) complex was prepared successfully using an in-house synthesized PDTMP ligand and ¹⁶⁶ HoCl ₃ . Ho-166 chloride was obtained by thermal neutron irradiation (1 × 10 ¹³ n/cm ² /s) of natural Ho (NO ₃ ) ₃ samples (specific activity = 3-5 GBq/mg), dissolved in acidic media. Radiochemical purity of ¹⁶⁶ Ho-PDTMP was checked by instant thin layer chromatography (>99%). Stability studies of the complex in the final preparation and in the presence of human serum were performed up to 72 h. The biodistribution of ¹⁶⁶ Ho-PDTMP and ¹⁶⁶ HoCl ₃ in wild-type rats was checked in animal tissues up to 48 h. The produced ¹⁶⁶ Ho-PDTMP properties suggest a possible new bone palliative therapeutic to overcome the metastatic bone pains.

The synthesis, radiolabeling and first biological evaluation of a new 166Ho-complex for radiotherapy of bone metastases

In this study, the 166Ho-triethylene tetramine hexa (methylene phosphonic acid) (166Ho-TTHMP) complex was prepared as a bone palliation agent. The complex was successfully prepared using an in-house synthesized TTHMP ligand and [166Ho]HoCl3. Ho-166 chloride was obtained by thermal neutron irradiation (1×1013 n cm−2 s−1) of natural Ho(NO3)3 samples, followed by radiolabeling and stability studies. Biodistribution studies were also performed in wild type rats. The complex was prepared with the specific activity of 3–5 GBq/mg and a high radiochemical purity > 99%, (checked by ITLC). The 166Ho-TTHMP complex was stable in the final preparation and in the presence of human serum (> 90%) up to 72 h. The biodistribution of 166Ho-TTHMP in wild-type rats demonstrated significant bone uptake compared to 166HoCl3 up to 48 h. SPECT imaging of the radiolabeled compound was demonstrated to be in complete accordance with the biodistribution data. The major uptake was observed for long bones including thigh bones as well as skull and also knee and vertebrae. Primary properties of 166Ho-TTHMP demonstrate that this new therapeutic agent can be a good choice for metastatic bone pains.

Palliation of painful metastatic disease involving bone with imaging-guided treatment: comparison of patients' immediate response to radiofrequency ablation and cryoablation

OBJECTIVE

The purpose of this article was to compare periprocedural analgesic requirements and hospital length of stay for treatment of patients with painful metastatic tumors involving bone using either percutaneous radiofrequency ablation (RFA) or cryoablation.

MATERIALS AND METHODS

A retrospective review was conducted of patients who underwent either imaging-guided cryoablation or imaging-guided RFA for painful metastatic tumors involving bone. The total analgesic usage for 24 hours after the procedure was expressed as a standard morphine-equivalent dose. Analgesic usage at admission served as a baseline for comparison. Total hospital stay was used as an additional measurement of procedure-related morbidity.

RESULTS

Fifty-eight patients underwent either cryoablation (n = 36) or RFA (n = 22) for painful metastatic tumors involving bone. Twenty-two primary tumors were treated. The most common treatment site was the pelvis (n = 31). There was no significant difference between the two groups with regard to tumor histologic type (p = 0.52) and location (p = 0.72). The median tumor diameter was 4.4 cm for the cryoablation group and 5.0 cm for the RFA group (p = 0.63). Pretreatment pain scores, measured on a scale of 0 to 10, were not significantly different between the two groups: 6.5 for cryoablation and 6.0 for RFA (p = 0.78). Analgesic use in the 24 hours immediately after the procedure decreased significantly by 24 morphine-equivalent doses after cryoablation, whereas it increased by a median of 22 morphine-equivalent doses after RFA (p = 0.03). Total hospital length of stay for patients undergoing cryoablation was a median of 2.5 days less than that for patients receiving RFA (p = 0.003).

CONCLUSION

The use of cryoablation compared with RFA is associated with a greater reduction in analgesic dose and shorter hospital stays after the procedure in the perioperative time frame.

Pharmacological treatment of neuropathic cancer pain: a comprehensive review of the current literature

Neuropathic cancer pain (NCP), commonly encountered in clinical practice, may be cancer-related, namely resulting from nervous system tumor invasion, surgical nerve damage during tumor removal, radiation-induced nerve damage and chemotherapy-related neuropathy, or may be of benign origin, unrelated to cancer. A neuropathic component is evident in about 1/3 of cancer pain cases. Although from a pathophysiological perspective NCP may differ from chronic neuropathic pain (NP), such as noncancer-related pain, clinical practice, and limited publications have shown that these two pain entities may share some treatment modalities. For example, co-analgesics have been well integrated into cancer pain-management strategies and are often used as First-Line options for the treatment of NCP. These drugs, including antidepressants and anticonvulsants, are recommended by evidence-based guidelines, whereas, others such as lidocaine patch 5%, are supported by randomized, controlled, clinical data and are included in guidelines for restricted conditions treatment. The vast majority of these drugs have already been proven useful in the management of benign NP syndromes. Treatment decisions for patients with NP can be difficult. The intrinsic difficulties in performing randomized controlled trials in cancer pain have traditionally justified the acceptance of drugs already known to be effective in benign NP for the management of malignant NP, despite the lack of relevant high quality data. Interest in NCP mechanisms and pharmacotherapy has increased, resulting in significant mechanism-based treatment advances for the future. In this comprehensive review, we present the latest knowledge regarding NCP pharmacological management.

Production, quality control and pharmacokinetic studies of Ho-EDTMP for therapeutic applications

¹⁶⁶Ho-EDTMP is a major therapeutic agent which is widely used in bone palliation therapy. In this study, a ¹⁶⁶Ho-EDTMP complex was prepared successfully using an in-house synthesized EDTMP ligand and ¹⁶⁶HoCl₃. Ho-166 chloride was obtained by thermal neutron irradiation (1 × 10¹³ ncm⁻²s⁻¹) of natural Ho(NO₃)₃ samples (specific activity = 3–5 GBq/mg), dissolved in acidic media. The radiochemical purity of ¹⁶⁶Ho-EDTMP was checked by ITLC (>99%) and stability studies in presence of human serum and final preparation were performed. The biodistribution of ¹⁶⁶Ho-EDTMP and ¹⁶⁶HoCl₃ in wild-type rats was checked by scarification. SPECT imaging of ¹⁶⁶Ho-EDTMP was also performed in wild-type rats. A comparative accumulation study for ¹⁶⁶Ho-EDTMP and ¹⁶⁶HoCl₃ was performed for vital organs up to 48h. Significant bone accumulation (>70%) of the tracer in 48h was observed.

Complexation of 188Re-phosphonates: in vitro and in vivo studies

MDP (methylenediphosphonate) and HEDP (hydroxyethylidene diphosphonate), both diphosphonates, and EDTMP (ethylenediamine tetramethylene phosphonic acid), a tetraphosphonate ligand, have been previously labeled with 188Re for use in metastatic bone-pain palliation. The aim of this study was a comparison between the three complexes 188Re-MDP, 188Re-HEDP and 188Re-EDTMP concerning the complexation conditions, in order to achieve maximum yield, stability and bone uptake. Methods: MDP was dissolved in water and HEDP and EDTMP were dissolved in NaOH 1N followed by reduction of pH with HCl 1N. To all mixtures stannous chloride and 188Re4 - were added in a nitrogen atmosphere. The preparations were heated in boiling water bath for 15min. Yield as well as radiochemical stability was estimated by ITLC. Different concentrations of phosphonates and stannous chloride were evaluated. Biodistribution studies in Swiss mice were done for the three 188Re-phosphonates that presented the best radiochemical yield. The optimal ligand concentration for maximum complexation was 85.2mM for MDP, 72.8mM for HEDP and 45.8mM for EDTMP. The best amount of SnCl2·2H2O} was 1.5mg/mL for 188Re-HEDP and 1mg/mL for both 188Re-MDP and 188Re-EDTMP. In these conditons the three complexes showed a complexation rate above 95. Reasonable radiochemical stability for 24 hours was achieved by 188Re-EDTMP when employing ascorbic acid. All products showed a great uptake by the kidneys. 188Re-EDTMP had the greatest uptake by femur (3.1±0.2 ID/g) followed by 188Re-MDP (1.2±0.1 ID/g) and 188Re-HEDP (1.0±0.1 ID/g), 4 hours post injection. 188Re-EDTMP displayed a femur bone/muscle ratio of 28.5, 188Re-MDP 4.9 and 188Re-HEDP 4.9. In conclusion 188Re-EDTMP demonstrated the best potential as a radiopharmaceutical for bone cancer pain relief, encouraging further dosimetric studies and clinical trials.

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.

Changes in the Levels of CD4+ and CD8+ T-Lymphocytes After Strontium-89 Chloride Therapy for Painful Bone Metastases in Patients Correlate with Treatment Efficacy

The aim of this study was to evaluate changes in the peripheral blood CD(4)(+) and CD(8)(+) T-lymphocyte populations following strontium-89 chloride ((89)SrCl(2)) therapy for painful bone metastases and to relate these changes to a therapeutic response. Forty-two (42) patients with painful bone metastases were treated with 148 MBq (4 mCi) of (89)SrCl(2). Blood samples were drawn before and monthly for 6 months after the treatment. CD(4)(+) and CD(8)(+) T-lymphocyte levels were measured using flow cytometry. The number of bone metastases and the pain score were used to assess the effect of therapy. Before the administration of (89)SrCl(2), the ratio of CD(4)(+) to CD(8)(+) T-lymphocytes was lower in patients with bone metastases than in the control subjects (p < 0.01); after therapy, the ratio increased up to the fourth month and then gradually declined to pretreatment levels. Responders had higher post-therapeutic ratios of CD(4)(+) to CD(8)(+) than nonresponders. There was a good correlation between the ratio of CD(4)(+) to CD(8)(+) and both the number of bone metastases and the pain score. The ratio of CD(4)(+) to CD(8)(+) T-lymphocytes correlated strongly with the response of bone metastases to (89)SrCl(2), and therefore, may be used as an indicator of (89)SrCl(2) efficacy.

Diagnostic and therapeutic use of radioisotopes for bony disease in prostate cancer: Current practice

Nuclear medicine techniques continue to be important non-invasive imaging tools assisting the diagnosis, monitoring and--in some cases--treatment of prostate cancer. Bone scintigraphy was the premier modality to have an extensive role in the staging of prostate cancer and has remained an integral tool for over three decades in the assessment of newly diagnosed disease or in follow-up staging. Therapeutic treatment and palliation of disseminated disease, particularly in the skeleton, has also been successful with several radioisotopes including strontium-89 chloride. Despite advances in nuclear medicine techniques and molecular imaging technology such as positron emission tomography and radioimmunoscintigraphy, bone scintigraphy still remains the gold standard in the assessment of osseous metastatic disease in prostate cancer. Thus, it is important to continually review the modalities that have remained important over time and not just to focus on newer technologies. This article summarizes the current diagnostic and therapeutic use of radioisotopes for bony disease in prostate cancer with particular reference to radionuclide bone scintigraphy and positron emission tomography.

Image-guided therapies in orthopedic oncology

The treatment of patients who have malignancies of bone often require multidisciplinary care. The aim of this review is to outline percutaneous techniques that may be useful for the diagnosis and treatment of these patients. In particular, the existing procedures of percutaneous biopsy, alcoholization (ethanol ablation), vertebroplasty, kyphoplasty, osteoplasty, radiofrequency ablation, laser photocoagulation, and vascular embolization are reviewed. Aspects of each technique, including mechanism of action, patient selection, treatment technique, and recent patient outcome are presented.

Osteoprotegerin in prostate cancer bone metastasis

Osteoprotegerin (OPG), a critical regulator of osteoclastogenesis, is expressed by prostate cancer cells, and OPG levels are increased in patients with prostate cancer bone metastases. The objective of this study was to investigate the effects of OPG overexpression on prostate cancer cells and prostate cancer/bone cell interactions in vitro and in vivo. OPG-transfected C4-2 cells expressed 8.0 ng OPG per mL per 10(6) cells, whereas no OPG was detected in the media of C4-2 cells transfected with a control plasmid. OPG overexpressed by C4-2 cells protected these cells from tumor necrosis factor-related apoptosis-inducing ligand-induced apoptosis and decreased osteoclast formation. Subcutaneous OPG-C4-2 and pcDNA-C4-2 tumors exhibited similar growth and take-rate characteristics. However, when grown in bone, tumor volume was decreased in OPG-C4-2 versus pcDNA-C4-2 (P=0.0017). OPG expressed by C4-2 cells caused increases in bone mineral density (P=0.0074) and percentage of trabecular bone volume (P=0.007), and decreases in numbers of osteoblasts and osteoclasts when compared with intratibial pcDNA-C4-2 tumors (P=0.003 and P=0.019, respectively). In summary, our data show that increased expression of OPG in C4-2 cells does not directly affect proliferation of prostate cancer cells but indirectly decreases growth of C4-2 tumors in the bone environment. Our data also show that OPG expressed by C4-2 cells inhibits bone lysis associated with C4-2 bone metastasis, which results in net increases in bone volume. We therefore hypothesize that OPG expressed in prostate cancer patient bone metastases may be at least partially responsible for the osteoblastic character of most prostate cancer bone lesions.

Treatment of bone pain secondary to metastases using samarium-153-EDTMP

CONTEXT

More than 50% of patients with prostate, breast or lung cancer will develop painful bone metastases. The purpose of treating bone metastases is to relieve pain, reduce the use of steroids and to maintain motion.

OBJECTIVE

To evaluate the use of samarium-153-EDTMP (153Sm-EDTMP) for the treatment of bone pain secondary to metastases that is refractory to clinical management.

TYPE OF STUDY

Retrospective.

SETTING

Division of Nuclear Medicine, Universidade Estadual de Campinas (Unicamp).

METHODS

Fifty-eight patients were studied (34 males) with mean age 62 years; 31 patients had prostate cancer, 20 had breast cancer, three had lung cancer, one had lung hemangioendothelioma, one had parathyroid adenocarcinoma, one had osteosarcoma and one had an unknown primary tumor. All patients had multiple bone metastases demonstrated by bone scintigraphy using 99mTc-MDP,and were treated with 153Sm-EDTMP. Response to treatment was graded as good (pain reduction of 50-100%), intermediate (25-49%) and poor (0-24%).

RESULTS

All patients showed good uptake of 153Sm-EDTMP by bone metastases. Among the patients with prostate cancer, intermediate or good response to therapy occurred in 80.6% (25 patients) and poor response in 19.4% (6). Among the patients with breast cancer, 85% (17) showed intermediate or good response to therapy while 15% (3) showed poor response. All three patients with lung cancer showed poor response to treatment. The lung hemangioendothelioma and unknown primary lesion patients showed intermediate response to treatment; the osteosarcoma and parathyroid adenocarcinoma patients showed good response to treatment. No significant myelotoxicity occurred.

DISCUSSION

Pain control is important for improving the quality of life of patients with advanced cancers. The mechanism by which pain is relieved with the use of radionuclides is still not yet completely understood, however, the treatment is simple and provides a low risk of mielotoxicity.

CONCLUSION

Treatment with 153Sm-EDTMP can control the pain secondary to bone metastases effectively in most patients with breast and prostate cancer without significant side effects.

Immunohistochemical study of receptor activator of nuclear factor kappa-B ligand (RANK-L) in human osteolytic bone tumors

BACKGROUND AND OBJECTIVES

Osteolytic bone tumors produce intercellular signaling proteins that regulate bone remodeling by altering the rates of osteoclast and osteoblast differentiation and activity. This report examines osteolytic bone tumor expression of receptor activator of nuclear factor B-ligand (RANK-L), a cytokine that is arguably the most critical regulator of osteoclast differentiation and activation.

METHODS

This prospective immunohistochemical study examined RANK-L expression in frozen tissues from sixteen surgical specimens of patients who underwent surgery for the treatment of osteolytic bone tumors between 1999 and 2000.

RESULTS

RANK-L was positive in 13 of the 16 cases. Primary benign bone tumors, primary malignant bone tumors, and metastasis to bone were positive for RANK-L.

CONCLUSIONS

The cells in some, but not all, osteolytic tumors produce the cytokine RANK-L. Further study is necessary to determine in which specific tumors RANK-L is the cytokine responsible for increased osteoclastic activity, and to develop possible therapeutic use of RANK-L antagonists such as osteoprotegerin (OPG).

Update on pain management for advanced genitourinary cancer

PURPOSE

Pain is a significant problem in many patients with genitourinary malignancy at all stages of disease. Optimal pain control becomes a primary concern as disease progresses and other therapies are exhausted. The selection of the most appropriate therapy becomes difficult without an understanding of the underlying mechanisms of pain and the available therapies.

MATERIALS AND METHODS

A review of the literature regarding the mechanisms and assessment of pain syndromes was performed. All available therapies were investigated with respect to conservative management with opioid medications and adjuvant drugs, and the indications for invasive techniques.

RESULTS

Increased understanding of the mechanisms and classification of pain syndromes has led to improved assessment and treatment. Despite these advances a significant number of patients have inadequate pain control and the education of treating physicians remains an important target for improving this situation.

CONCLUSIONS

Opioid medication is the mainstay of therapy in the majority of patients but with the appropriate addition of other adjuvant drugs patients may achieve optimal pain control without unwanted side effects. A few patients benefit from more invasive techniques, including plexus blocks and neuraxial infusion therapy, and the indications for these treatments are discussed. These therapies have largely superseded neuroablative procedures that are more destructive and associated with higher morbidity.

The use of anti-inflammatory drugs in cancer pain

The role of non-steroidal anti-inflammatory drugs (NSAIDs) in cancer pain has been well established in the treatment of mild pain and also alone or in association with opioids for the treatment of moderate to severe pain. Acutely, NSAIDs may be more than mild analgesics, and may provide additional analgesia when combined with opioids. However, NSAIDs have ceiling effects and there is no therapeutic gain from increasing dosages beyond those recommended. As there is no clearly superior NSAID, the choice should be based on experience and the toxicity profile that probably relates to the COX-1:COX-2 ratio. Among the older drugs, ibuprofen seems to have these properties.Non-steroidal anti-inflammatory drugs have been shown to have an opioid-sparing effect. Although the value of a simple narcotic-sparing effect may be questioned in cancer pain treatment, the use of NSAIDs may be useful when the increase in opioid dosage determine the occurrence of opioid toxicity. Like opioids, NSAIDs should not be considered analgesics for a specific type or cause of pain. There is a lack of evidence for any difference between different routes of NSAIDs administration. The long-term toxicity of NSAIDs in cancer pain is poorly defined due to a lack of studies. A variety of strategies have been used in an attempt to reduce the risks associated with NSAID therapy. Those NSAIDs that are weak COX-1 inhibitors may be preferred. In addition, concomitant administration of misoprostol is recommended in patients at increased risk for upper gastrointestinal complications.

Re-HEDP : pharmacokinetic characterization, clinical and dosimetric evaluation in osseous metastatic patients with two levels of radiopharmaceutical dose

BACKGROUND: A study for pain relief therapy with 188Re-HEDP was done in patients with bone metastases secondary to breast and prostate cancer. MATERIALS AND METHODS: Patients received 1.3 or 2.2 GBq, in single or multiple doses. Platelets, white and red cells were evaluated during 11 weeks. Pharmacokinetic characterization was done from blood and urine samples for 5 patients along 24 hours. Urinary excretion was evaluated in other 16 patients during 6 hours. Bone uptake was estimated as remaining activity in whole body. Scintigraphic images were acquired at 2 and 24 hs post-administration. Absorbed dose in bone marrow was estimated with Mirdose3. Analgesics intake and pain score were daily recorded. Tumour markers (PSA, and Tn-structure) were monitored in 9 patients during 4 to 6 months. Single doses of low activity (1.3 GBq) were given to twelve patients. Nine patients received multiple doses. RESULTS: All except one patient had normal levels of platelets, white and red cells. Remaining dose in blood at 2 hours was 9%. Urinary elimination was 58%. Bone uptake at 24 hours was 43% (mean value; n = 5). No changes of the haematological parameters were detected along follow-up period. Pain relief was evidenced by decrease or supression of opioid analgesic and by subjective index. PSA showed a decrease in prostate cancer patients (n = 4). Tn-structure showed a significant increase after 4 to 8 months. CONCLUSION: Single or multiple dose scheme could be safely used, with administered activity of 188Re-HEDP up to 60 mCi, with low bone marrow absorbed doses.

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.

Neurophysiology of Cancer Pain: From the Laboratory to the Clinic

Pain is one of the most distressing symptoms associated with cancer. Basic science research has provided much insight into the mechanisms of peripheral and central pain and the actions of new drugs. Despite these advances, pain accompanying malignancy can be difficult to treat. Pain most commonly presents when the tumor has invaded somatic,visceral, or neural structures. An understanding of pain mechanisms is essential when deciding on the appropriate treatment. New therapeutic options have been developed and will hopefully provide clinicians with tools to successfully alleviate cancer pain.

Neurophysiology of cancer pain

BACKGROUND

Recent basic science research has greatly added to our knowledge of pain mechanisms. Application of this knowledge to cancer pain syndromes has led to new and innovative approaches to cancer pain management.

METHODS

The mechanisms involved in the three main cancer pain syndromes (somatic, visceral, and neuropathic) are reviewed, and various therapeutic options are discussed.

RESULTS

Advances in knowledge in neurophysiology, neuroanatomy, and pharmacology have allowed a greater understanding of the peripheral and central mechanisms of pain. New drugs and interventional techniques based on this knowledge have improved the control of cancer pain.

CONCLUSIONS

Understanding the neurophysiology of cancer pain promotes use of the most appropriate palliative measures for pain control.

Analgesic effects of nonsteroidal anti-inflammatory drugs in cancer pain due to somatic or visceral mechanisms

The role of nonsteroidal anti-inflammatory drugs (NSAIDs) is well established in the treatment of cancer pain. This class of drugs is considered particularly effective in pain due to somatic mechanisms, although proof of this observation is lacking. To ascertain whether NSAIDs are more effective in specific nociceptive forms of cancer pain, they were administered alone or added to opioids in 32 patients with a sole pain mechanism, somatic pain due to bone metastases (17 patients) or visceral pain (15 patients), respectively. Pain intensity, mean doses of opioids used, and symptoms were recorded after starting NSAID. A significant reduction in pain intensity was found at 3, 7, and 14 days. No differences in pain intensity between the two groups were observed. However, patients with a visceral mechanism required higher opioid doses after a week of treatment. No differences in adverse effects were reported. NSAIDs may be useful drugs in the management of cancer pain, regardless of the mechanism of pain involved. The incidence of adverse effects during prolonged administration should be assessed in future studies.

Unsealed source therapy of painful bone metastases: an update

Pain in patients with cancer metastatic to bone is a significant cause of morbidity and of referrals from general practice and specialist physicians. Management typically utilizes radiation therapy and the graduated use of opiate analgesics. Bone-seeking radiopharmaceuticals have provided a new option to these management strategies, which is effective and cost effective. Strontium 89 is now in routine clinical use, while rhenium 186 hydroxyethylidene diphosphonate (HEDP) and samarium 153 ethylenediaminetetramethylene phosphonate (EDTMP) are in Phase III trials and tin 117m (4+) diethylene triaminepentacetic acid (DTPA) is in Phase I trials. Evidence taken primarily from the Strontium 89 trial, shows unsealed source therapy with these bone-seeking radiopharmaceuticals to be effective in palliating pain, improving quality of life, reducing the rate at which new painful sites develop, reducing requirements for additional radiation therapy, and reducing lifetime management costs. Indications and contraindications to therapy have now been defined, and retreatment is an option with all radiopharmaceuticals.

Radiation doses of yttrium-90 citrate and yttrium-90 EDTMP as determined via analogous yttrium-86 complexes and positron emission tomography

Yttrium-90 is used for palliative therapy for the treatment of skeletal metastases, but because it is a pure beta- emitter, data on the pharmacokinetics and radiation doses to metastases and unaffected organs are lacking. To obtain such data, the present study employed yttrium-86 as a substitute for 90Y, with detection by positron emission tomography (PET). The study compared the properties of two different 86Y complexes - 86Y-citrate and 86Y-ethylene diamine tetramethylene phosphonate (EDTMP) - in ten patients with prostatic cancer who had developed multiple bone metastases (the ten patients being divided into two groups of five). Early dynamics were measured up to 1 h post injection (p.i.) over the liver region, followed by subsequent whole-body PET scans up to 3 days p.i. Absolute uptake data were determined for normal bone, bone metastases, liver and kidney. Radiation doses were calculated according to the MIRD recommendations. Based on the pharmacokinetic measurements of the distribution of the 86Y complexes, it was possible to calculate radiation doses for the bone metastases and the red bone marrow delivered by complexes containing 90Y. In 1 cm3 of bone metastasis, doses of 26+/-11 mGy/MBq and 18+/-2 mGy/MBq were determined per MBq of injected 90Y-citrate and 90Y-EDTMP, respectively. The doses to the bone marrow were 2.5+/-0.4 mGy/MBq for 90Y-citrate and 1.8+/-0.6 mGy/MBq for 90Y-EDTMP. 86Y and PET provide quantitative information applicable to the clinical use of 90Y. This method may also be useful for the design of other 90Y radiopharmaceuticals and for planning radiotherapy dosages.

Use of nonsteroidal anti-inflammatory drugs in cancer

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used in cancer, yet they are also responsible for many, often serious, adverse effects. This review examines the various mechanisms through which NSAIDs work. It looks at the experience built up in using NSAIDs in cancer pain in general, but then particularly examines whether the evidence available supports the claim often made that these drugs have a specific role in relief of pain from bony metastases. Criteria for choosing one NSAID over another, including adverse effect profiles, efficacy and tolerability, are considered, as are methods for improving the safe use of these drugs.

Current status of systemic intravenous radiopharmaceuticals for the treatment of painful metastatic bone disease

PURPOSE

Intractable bone pain secondary to bone metastasis from prostate, lung, breast, and other malignancies is a major problem in the management of the oncological patient. Because a number of factors are implicated in the pathophysiology of bone pain, a multidisciplinary approach in its assessment and treatment is often required. Treatment often includes the use of analgesic drug therapy; however, radiation therapy, hormonal therapy, chemotherapy, and surgery may also be needed.

METHODS AND MATERIALS

The use of systemic radionuclide therapy may often be helpful to relieve bone pain and improve the quality of life. In the setting of diffuse bone metastasis, intractable to conventional therapy, various radioisotopes have been advocated. These include phosphorous-32, iodine-131, strontium-89, yttrium-90, samarium-153, and rhenium-186, often as either the anionic phosphate or as a ligand (HEDP, EDTMP).

RESULTS

When these agents are used, pain relief often occurs in approximately 2-4 weeks and lasts several weeks to months with responses seen in 60-80% of patients, depending on the extent of disease and stage the patient is treated. Retreatment has been possible in certain cases with further palliation being offered and improvement in the various quality of life parameters being noted.

CONCLUSION

Myelotoxicity has been a limiting factor with certain isotopes and has led to the development of less toxic bone seeking agents. Although these each have unique physical and biokinetic properties requiring different doses and protocols for administration, they all appear to localize in osteoblastic metastatic sites in sufficient amounts to provide bone pain palliation.