Pain Outcomes in Patients with Metastatic Castration-Resistant Prostate Cancer Treated with 223Ra: PARABO, a Prospective, Noninterventional Study.

223Ra, a targeted α-therapy, is approved for the treatment of patients with metastatic castration-resistant prostate cancer (mCRPC) who have bone metastases. In the phase 3 ALSYMPCA study, 223Ra prolonged survival and improved quality of life versus placebo. Our real-world study, PARABO, investigated pain and bone pain-related quality of life in patients with mCRPC and symptomatic bone metastases receiving 223Ra in clinical practice. Methods: PARABO was a prospective, observational, noninterventional single-arm study conducted in nuclear medicine centers across Germany (NCT02398526). The primary endpoint was a clinically meaningful pain response (≥2-point improvement from baseline for the worst-pain item score in the Brief Pain Inventory-Short Form). Results: The analysis included 354 patients, who received a median of 6 223Ra injections (range, 1-6). Sixty-seven percent (236/354) received 5-6 injections, and 33% (118/354) received 1-4 injections. Of 216 patients with a baseline worst-pain score of more than 1, 59% (128) had a clinically meaningful pain response during treatment. Corresponding rates were 67% (range, 98/146) with 5-6 223Ra injections versus 43% (range, 30/70) with 1-4 injections, 60% (range, 60/100) in patients with no more than 20 lesions versus 59% (range, 65/111) in those with more than 20 lesions, and 65% (range, 69/106) in patients without prior or concomitant opioid use versus 54% (range, 59/110) in those with prior or concomitant opioid use. Mean subscale scores (pain severity and pain interference) on the Brief Pain Inventory-Short Form improved during treatment. Conclusion: 223Ra reduced pain in patients with mCRPC and symptomatic bone metastases, particularly in patients who received 5-6 injections. The extent of metastatic disease did not impact pain response.

Tc-99m-PSMA-SPECT/CT Is Superior to Tc-99m-MDP-SPECT/CT in the Staging of Prostatic Cancer with Osseous Metastases after External Beam Radiotherapy.

In the reported patient with advanced prostate cancer, a bone scan showed a false positive finding in thoracic vertebrae bone metastasis after external beam radiotherapy 2 months ago. An additional Tc-99m-prostate-specific membrane antigen scan showed a negative finding, although nonirradiated iliac bone metastasis was concordantly positive in both scans. The decrease in prostate-specific antigen-level from 156.6 ng/mL to 2.3 ng/mL indicates a strong effect of treatment, hence supporting false positivity in bone scan by flare phenomenon.

Radiosynovectomy is effective in thumb basal joint arthritis.

OBJECTIVE: Radiosynovectomy (RSO) describes the internal low-dose radiotherapy of the synovia via intra-articular administration of small radioactive particles. Since the introduction of biologics, the main aetiology of arthritic joints for RSO changed to mostly osteoarthritis with concordant change in typically affected joints. Thus, the effect of RSO in thumb basal joint arthritis (BJTh) with focus on osteoarthritis needs to be explored. DESIGN: From 2017 to 2020, 219 BJTh were treated in 125 patients, 17 patients with rheumatoid arthritis (RA) and 108 patients with osteoarthritis (OA). The therapeutic effect was assessed using a four-step subjective scoring. RESULTS: 20% of the treated joints were symptom free, 48% had a very good response, 16% slight and 16% no response. RSO was performed in 71 patients singularly and in 54 patients repetitively. The mean response duration was 6.8 months with a maximum of 48 months. 35% of patients had post-therapeutic pain relief followed by relapse after 3 months. Response duration showed no significant difference the between first and repetitive therapy, primary responder and primary non-responder and RA and OA. CONCLUSION: In thumb basal joint arthritis, RSO leads to response rates from 66 to 79%, mean response duration from 6 to 12 months and individual response duration 48 months. The present results are in line with previously published response rates in smaller joints. In respect to 35% of patients with relapse within 3 months post-therapy, we recommend a primary follow-up after 3-4 months.

90Y Radiosynovectomy in Persistent Synovitis Caused by Knee Replacement: Long-Term Outcome.

INTRODUCTION: After knee replacement, therapy resistant, persistent synovitis is a common issue, which causes effusion and pain, and leads to loosing. It has been hypothesized that radiosynovectomy (RSO) is useful in these patients. MATERIALS AND METHODS: A cohort of 55 patients with 57 knee replacements and persistent synovitis underwent RSO using 4.9 ± 0.24 mCi (182 ± 9 MBq) of Y-citrate. The number of RSOs ranged from 1 to 4. Bone scans before and 3 months after every RSO were performed. Long-term follow-up ranged from 0.8 to 7.6 years with a mean of 23.2 months. For qualitative analysis, an established 4 steps scoring was used. For quantification, the uptake was determined within the Tc-MDP scintigraphy blood pool phase before and after therapy. RESULTS: Long-term response was in 27% with excellent, 24% good, 30% weak, and 20% no response. The duration of response was 12.0 ± 12.0 months (maximum, 54 months). In patients with repeated treatment, the effect after the first therapy was lesser than in patients who received a single treatment in total. However, 3 months after the last RSO, patients with repeated treatment showed a similar effectiveness than single treated patients. At the end of long-term follow-up, patients with repeated RSOs had a higher effectiveness at similar duration response. In bone scan, 65% of patients showed a reduction of uptake. When comparing subjective and objective response, 78% of patients showed a concordance in both symptoms and scintigraphy. Pilot histological analysis revealed that the synovitis is triggered by small plastic particles. CONCLUSIONS: We concluded that RSO is an effective therapy in patients with knee replacement and persistent synovitis with high long-term response. Repeated treatment leads to a stronger long-time response.

99mTc-Hynic-TOC imaging in the diagnostic of neuroendocrine tumors.

The aim of this study was to assess the potential of 99mTc-Hynic-TOC imaging in the primary diagnosis and follow-up of midgut neuroendocrine tumors (NETs). In comparison to 111In-octreotide, 99mTc-Hynic-TOC has a higher imaging quality and leads to a lower radiation absorption in patients. 99mTc-Hynic-TOC was used for assessing primary diagnosis (n = 14) and during follow-up (n = 17) in patients with NETs. The scintigraphic findings were compared with computed tomography scans and follow-up. In 31 patients, 34 somatostatin receptor scans using 99mTc-Hynic-TOC were performed. The primary diagnoses were midgut NET. The scintigraphy was true positive in 17 patients, true negative in 9, false negative in 4, and false positive in 1. From these data, a sensitivity of 81%, specificity of 90%, positive predictive value of 94%, and negative predictive value of 69% were calculated. In summary, 99mTc-TOC represents a useful radiotracer in imaging SSTR-expressing tumor lesions with slightly higher sensitivity, higher imaging quality, and lower radiation exposure for patients compared to 111In-octreotide. A 1-day double-acquisition protocol should be used to reduce false-positive findings of the gut.

188Re-HEDP therapy in the therapy of painful bone metastases.

For bone-targeted radionuclide therapy (BTRT), different commercial radiopharmaceuticals are available such as strontium-89, 186Rhenium-hydroxyethylidene diphosphonate (186Re-HEDP), Samarium-153-ethylenediamine tetramethylene phosphonic acid, and radium-223. Unfortunately, the commercial available radiopharmaceuticals are very expensive (from 1,200 to 36,000€ per patient in Europe). The 188W/188Re generator is an ideal source for the long-term (4-6 months) continuous availability of 188Re suitable for the preparation of radiopharmaceuticals for different radionuclide therapies. Labeling at HEDP, it can use cost-effective for BTRT, if enough patients are available for therapy. And so, 188Re-HEDP is the ideal candidate in developing countries which high population to replace the other agents. Two German groups documented a response rate of 80% without any severe side effects and similar bone marrow toxicity compared to the other compounds for 188Re-HEDP. Using 188Re-HEDP in repeated treatments, a prolonged overall survival of repeated to single application was observed (from 4.5 months for single to 15.7 months using ≥≥3 applications).

Radiosynoviorthesis of acromioclavicular joint using 169Er-citrate: prospective evaluation of efficacy.

BACKGROUND: There is a clinical need for therapeutic alternative in patients with persisting painful arthritis of AC-joint and failure of previous treatments. However, no radiopharmaceutical is currently explicitly approved for radiosynoviorthesis of acromioclavicular joint. The aim of our study was to prospectively assess the efficacy and safety of radiosynoviorthesis of acromioclavicular joint using erbium-169 citrate. MATERIAL AND METHODS: Radiosynoviorthesis of acromioclavicular joint was performed in 51 consecutive patients (18 males, 33 females) mean age 64.3 (range 43.8-82.6, median 63.6) years with clinically confirmed arthritis of 85 acromioclavicular joints. The efficacy of RSO was reported by patients according to 10-step visual analogue scale of pain (VAS) (0 = no pain, 10 = most severe pain) at 6 months after radiosynoviorthesis and by ranking the global therapeutic effect of RSO in 4 categories (1 = the best effect, 4 = no change). To assess the variation of blood perfusion in treated joints, the efficacy of RSO was also evaluated by variation of target (acromioclavicular joint)/non-target (soft tissue) uptake ratio (T/NTR) of metylendiphosphonate (99mTc) measured as number of counts over region of interest on blood pool phase of two-phase bone scintigraphy performed before and 6 months after RSO. RESULTS: Radiosynoviorthesis was followed by significant decrease in VAS, mean - 3.1 (-47%). Excellent, good, moderate and bad response was observed in 57 (67%), 25 (29%), 1 (1%) and in 2 (2%) of acromioclavicular joints respectively. A significant correlation between decrease of T/NTR and variation of VAS in % (ρ = 0.532, p < 0.0001) and between T/NTR and subjective evaluation of therapeutic effect in scale 1-4 (ρ = 0.388, p = 0.0002) was observed. However, it was not possible to identify the cut-off value of relative decrease in T/NTR showing sufficient sensitivity and specificity to detect the therapeutic response. CONCLUSION: Results of this prospective study permit to conclude a good efficacy and safety of radiosynoviorthesis using erbium-169 citrate in a series of patients with arthritis of acromioclavicular joint in whom previous line(s) of treatment did not lead to satisfactory pain relief.

From palliative therapy to prolongation of survival: (223)RaCl2 in the treatment of bone metastases.

Patients with hormone-refractory prostate cancer often have multiple bone metastases. The resulting bone pain is associated with reduced life quality, increased cost of therapy and impairment of overall survival. Trials with bone-targeting ß-emitters have mostly showed an effect on alleviation of bone pain along with prolongation in survival, documented in only a limited number of patients. A randomized phase III trial (ALSYMPCA) using the α-emitter (223)RaCl2 (Xofigo®) showed for the first time, a longer overall survival of 3.6 months in treated patients as a sign of an antitumor effect. The time to first skeletal-related events was also significantly longer in the therapy group compared with placebo. Because of the short range of α-emitter, the bone marrow toxicity of radium therapy is low, and so this radionuclide could also be a candidate for combination with chemotherapy. The elimination of (223)RaCl2 is mainly through the gastrointestinal tract and side effects are mainly in this area. The procedure is similar to treatment with other bone-seeking agents and consists of six administrations of 50 kBq/kg bodyweight Xofigo®, repeated every 4 weeks. At present Xofigo® is only approved for hormone-refractory prostate cancer.

Dose-dependent histological alterations in the rat lung following intravenous application of Re-188-labeled microspheres.

PURPOSE: The objective of this study was to determine the dose-effect correlation of pneumopathy after application of Rhenium-188 microspheres (Re-188 MS) in an animal model using histological changes as an end-point. METHODS AND MATERIALS: Wistar rats received an intravenous injection of Re-188 MS yielding doses that ranged from ˜ 2 to ˜ 55 Gy. Lungs were removed after ˜ 25 weeks and prepared for histology. Sections were evaluated using a semi-quantitative 5-tiered score. Dose groups of 10 Gy intervals were statistically analyzed using the Chi-square test with respect to grade and extent of connective tissue accumulation, thickness of vessel walls and accumulation of alveolar macrophages (AM). RESULTS: There was a statistically significant increase in connective tissue content and extent in all dose groups compared to control lungs and at least between each other dose group. The steepest increase in connective tissue was at doses higher than 40 Gy. Starting from that dose, a statistically significant increase of AM accumulation and vessel wall thickness occurred. CONCLUSIONS: There was a clear dose-effect correlation between radiation dose and histological changes. These findings allow an estimation of potential normal tissue damage especially during tumor treatments of liver lesions with radioactive particles in patients with significant liver-to-lung shunts.

Efficacy of radiosynovectomy in rheumatoid arthritis.

In this retrospective study, we evaluated the effect of radiosynovectomy of patients with rheumatoid arthritis. Radiosynovectomy was performed in 577 joints of 137 rheumatoid patients. We applied 185 MBq yttrium-90 in knees (n = 58), 74-111 MBq rhenium-186 colloids in ankle (n = 50), wrists (n = 43) and shoulders (n = 35), and 15 to 37 MBq in finger (n = 298) and toe joints (n = 46). The effect of radiosynovectomy was scored in 4 subjective categories: excellent response (no symptoms); good response (significant reduction of symptoms); moderate response (slight decrease); and bad response (no change or worsening), of pain and/or swelling in treated joint 3 months after the procedure. Excellent or good response was observed in 57% of treated knees, 63% of shoulders, 60% of wrists, 64% of ankles, 54% of thumb bases, 55% of MCP's, 54% of PIP's, 53% of DIP's, and 54% of MTP's. Side effects associated to the RSO, i.e., swelling or transient increase of pain, were recorded in 7% of the patients that resolved within 1 month. No patient had any non-reversible skin alteration after treatment, only slight erythema was observed in 5 patients. Radiosynovectomy is effective and safe in the treatment of rheumatoid arthritis.

Radiation pneumopathy in the rat after intravenous application of (188)Re-labeled microspheres.

PURPOSE: To determine the dose dependence and kinetics of pneumopathy after systemic administration of rhenium-188 ((188)Re)-labeled microspheres in a rat model. METHODS AND MATERIALS: (188)Re-microspheres were injected intravenously into adult Wistar rats (n = 54, age, 8 ± 2 months). The rats were divided into 6 groups according to the intended absorbed dose in the lung (maximum 60 Gy). Gamma camera scans were used to estimate the individual whole lung doses. One control group (n = 5) received nonlabeled microspheres. The breathing rate was measured before and weekly after the treatment using whole body plethysmography until 24 weeks. An increase in the breathing rate by 20% compared with the individual pretreatment control value was defined as the quantal endpoint for dose-effect analyses. RESULTS: A biphasic increase in the breathing rate was observed. The first impairment of lung function occurred in Weeks 3-6. For late changes, the interval to onset was clearly dose dependent and was 17 weeks (10-30 Gy) and 10 weeks (50-60 Gy), respectively. The incidence of the response was highly dependent on the estimated lung dose. The median effective dose for an early and late response was virtually identical (19.9 ± 0.6 Gy and 20.4 ± 3.1 Gy, respectively). A significant correlation was found between the occurrence of an early and a late effect in the same rat, suggesting a strong consequential component. CONCLUSIONS: The effects of radiolabeled microspheres can be studied longitudinally in a rat model, using changes in the breathing rate as the functional, clinically relevant response. The isoeffective doses from the present study using radionuclide administration and those from published investigations of homogeneous external beam radiotherapy are almost similar.

The role of 123I-FP-CIT-SPECT in the differential diagnosis of Parkinson and tremor syndromes: a critical assessment of 125 cases.

(123)I-FP-CIT-SPECT is useful in the differential diagnosis of Parkinson's disease (PD) and tremor syndromes. Recently, there have been reports on normal nigrostriatal uptake of radio ligands in PD patients, referred to as scans without evidence of dopaminergic deficit (SWEDDs). Furthermore, a dopaminergic deficit has been described in some cases of different tremor types. We sought to clarify the occurrence of SWEDDs in PD and a possible association of various tremor types with PD. We performed a retrospective case analysis of 125 patients with diagnostically uncertain Parkinsonian or non-Parkinsonian tremor syndromes with clinical assessments and (123)I-FP-CIT-SPECT. A total of 36/40 (90%) patients with the predominant clinical feature of a postural and/or kinetic tremor showed normal DAT SPECT; 73/85 (86%) with predominant clinical symptoms of PD showed abnormal DAT SPECT with lower overall radio ligand uptake and a significant asymmetry contralateral to the clinically more affected side. In all, 4/40 (10%) of non-Parkinsonian tremor patients had abnormal DAT SPECT, but no corresponding asymmetry of radio ligand uptake. Probable essential tremor was considered clinically in follow-up assessments although final diagnosis of these four tremor cases remains inconclusive. A total of 12/85 (14%) clinically suspected PD patients had normal DAT SPECT (SWEDDs). Clinical reassessment identified two patients with dystonic tremor. Five patients with a positive response to levodopa remained unclear. In four cases of suspected PD with normal DAT SPECT, non-neurologic diseases were identified. One case showed a complete and spontaneous remission of symptoms. DAT SPECT offers an objective method to confirm or exclude a dopaminergic deficit in tremor predominant parkinsonism for clinically inconclusive cases. There was no evidence of a decrease in DAT binding in the majority of patients with postural and/or kinetic tremor. The striatal asymmetry index is a further helpful tool for differentiating PD from non-PD tremor syndromes.

Radiosynovectomy using yttrium-90, phosphorus-32 or rhenium-188 radiocolloids versus corticoid instillation for rheumatoid arthritis of the knee.

BACKGROUND: Radiosynovectomy (RSO) is widely used in rheumatoid arthritis (RA). Commercially available radiopharmaceuticals are costly, and therefore new agents may be of interest. Radiocolloids labelled with less costly and more accessible radionuclides are of interest to developing countries. We investigated the efficacy of different formulations in RA. METHODS: In a multicentre effort, a cohort of 99 RA patients with knee involvement underwent RSO. Sixty-eight patients were treated with 184 ± 4 MBq Y-90 silicate (Y-90), 15 patients with 53 ± 11 MBq P-32 colloid (P-32), and 16 patients with 451 ± 110 MBq of Re-188 tin colloid (Re-188). Corticosteroid group (CSG) consisting of 46 patients received an intra-articular instillation of 20-40 mg triamcinolone. Pain response was evaluated by a 10-step visual analogue scale (VAS) before, 1 month, 3 months, 6 months and 12 months following the procedure. RESULTS: In the RSO group (n = 99), pain relief by VAS from 6 ± 2 before to 5 ± 3, 4 ± 2, 3 ± 2 and 4 ± 2 at 1, 3, 6, 12 months after RSO was documented (Y-90 group: 6 ± 2 to 3 ± 2; P-32: 5 ± 2 to 3 ± 2, Re-188: 7 ± 2 to 4 ± 2 before vs. 6 months after therapy, respectively). The CSG VAS values were 6 ± 2 before and 5 ± 2, 4 ± 3, 5 ± 2 and 6 ± 2 at 1, 3, 6 and 12 months after corticosteroid instillation, respectively. Pain relief achieved with the three radiocolloid formulations did not differ significantly (P > 0.1). Pain relief at 12 months was more durable in RSO compared to CSG, P < 0.05. At 3 months, pain relief (>2 steps) was reported by 86% of RSO versus 67% of CSG, at 6 months 72 versus 46% and at 12 months 46 versus 21%. Side effects, i.e. swelling or transient pain increase, were recorded in 16% of patients but resolved within 1 month. CONCLUSION: Therapeutic efficacy of RSO for RA of the knee applying either P-32, Re-188 or Y-90 provides comparable results. Pain relief by RSO is longer lasting as compared to corticosteroid instillation.

Alpharadin, a 223Ra-based alpha-particle-emitting pharmaceutical for the treatment of bone metastases in patients with cancer.

Bone metastases occur in many patients with different forms of solid malignant tumors, particularly in advanced stages of prostate and breast cancer, and are commonly associated with increased morbidity and mortality. The resulting bone pain interferes with quality of life and thus requires effective treatment. However, various non-radiotherapeutic modalities such as analgesics, hormone therapy, orchidectomy, cytostatic and cytotoxic drugs, bisphosphonates and surgery are not universally effective. External-beam radiotherapy is suitable only for well-defined localized bone metastases, and extended field radiation is often accompanied by serious side effects. Therefore, systemic radionuclide therapy must be considered as a valuable and effective method of treatment in patients with widespread skeletal metastases. The alpha-emitter 223Ra-based Alpharadin is a new radiopharmaceutical under development by Algeta ASA in collaboration with Bayer Schering Pharma AG. Early clinical data demonstrated a significant decrease in bone-alkaline phosphatase levels following therapy with Alpharadin compared with placebo. Median time to PSA progression, median survival and pain relief were also superior to placebo, and no dose-limiting hematological toxicity was observed. A phase III trial for Alpharadin was ongoing at the time of publication.

Autoradiographic studies of rhenium-188-hydroxyethylidine diphosphonate in normal skeleton and osteoblastic bone metastases in a rat model of metastatic prostate cancer.

AIM: The quantitative distribution of bone-seeking radiopharmaceuticals in trabecular bone, cortical bone and in skeletal metastases is required for calculation of radiation-absorbed dose in radionuclide therapy. An animal model of intraosseous tumor cell administration was developed to simulate osteoblastic metastases for autoradiographic study of radionuclide localization. METHODS: In 45 Copenhagen rats R3327-MATLyLu syngeneic prostate cancer cells were given intraosseously in both the femori. Rhenium-188-hydroxyethylidine diphosphonate (HEDP) was administered intravenously 17+/-1 days after cells instillation and these animals were euthanized at 4, 24 and 48 h after injection of the radiopharmaceutical. The uptake of radiopharmaceutical was estimated in normal skeleton and the bone metastases by means of region of interest analysis using autoradiography. The tumor to nontumor ratio and the fractional uptake in cortical bone and trabecular bone were quantified. RESULTS: The uptake of rhenium-188-HEDP in cortical bone was 33.5% and in trabecular bones was 66.5% after 4 h, 34.6 and 65.4% after 24 h, and 35.9 and 64.1% after 48 h, respectively. Assuming a theoretic cortical-trabecular distribution of 50-50%, (MIRDOSE) calculation, radiation-absorbed dose to bone marrow was underestimated by 26%. In bone metastases, an inhomogeneous distribution with a minimal and maximal tumor to nontumor ratio of 3 : 1 and 14 : 1 after 4 h, 5 : 1 and 14 : 1 after 24 h, and 5 : 1 and 16 : 1 after 48 h was observed. CONCLUSION: The MIRDOSE model underestimates the radiation-absorbed dose to the bone marrow because of demonstrable differences in the uptake of rhenium-188-HEDP in cortical and trabecular bone and inhomogeneous uptake in skeletal metastases.

Radiosynoviorthesis (RSO): influencing factors and therapy monitoring.

OBJECTIVE: To evaluate the effectiveness of radiosynoviorthesis (RSO) in relation to joint type and underlying disease by both self-assessment of patients and scintigraphic assessment to determine conditions under which RSO might be preferable to the sole intra-articular corticoid injection. METHODS: Radiosynoviorthesis was performed on 136 patients for 424 joints [242 small, 130 medium-sized, and 52 large joints; 313 with rheumatoid arthritis (RA) and 111 with osteoarthritis (OA)]. The success of RSO was evaluated after 12 months by patients' estimation, and in 35 patients for 157 joints additionally by two-phase bone scintigraphy. The relative change in the scintigraphic uptake was compared with the patients' estimation. RESULTS: The subjectively estimated success rates for the small, medium-sized, and large joints were 89% (215/242), 86% (112/130), and 79% (41/52), and for RA and OA 89% (280/313) and 79% (88/111), respectively. The scintigraphically determined response rates for small and medium-sized joints were 81% (86/106) and 69% (35/51), respectively. There was a mismatch between patients' assessment and scintigraphic assessments in 18% (28/157) with 6 false-negative and 22 false-positive estimations using scintigraphy as the standard of reference. CONCLUSIONS: The success of RSO is higher in patients with RA than in patients with OA. For the finger, ankle, and wrist joints in RA, RSO is so promising that we would like to advocate its preference over the sole intraarticular corticoid injection. Perfusion bone scintigraphy can be used for therapy monitoring and earlier switching to RSO by showing that other therapies have failed.

Feasibility of high activity rhenium-188-microsphere in hepatic radioembolization.

BACKGROUND: This paper describes the feasibility of intra-arterial high-activity administration of (188)Re-microspheres. METHODS: Patients with unresectable colorectal liver metastases or hepatocellular cancer (HCC) received single treatments with (188)Re-microspheres. The administered activity was calculated to give a liver dose of 100 Gy. From post-therapeutic scans and urine sampling, the dose to the liver, metastases and bladder was calculated. Toxicity was assessed up to 3 months after administration by means of the Common Terminology Criteria for Adverse Events v3.0 (Trotti et al. CTCAE v3.0: development of a comprehensive grading system for the adverse effects of cancer treatment. Semin Radiat Oncol 2003;13(3):176-81). Response was evaluated on CT. RESULTS: 13.6 +/- 4.7 GBq (188)Re-microspheres was administered selective in the feeding artery of the tumour to 10 patients (3 x HCC and 7 x colorectal liver metastases). There was a low urinary excretion rate of 8.9 +/- 3.8% of administered activity within 96 h. The absorbed dose to the tumour, normal liver (excluding the tumour) and bladder was 10.24 +/- 5.02 Gy/GBq (128 +/- 47 Gy), 3.94 +/- 2.52 Gy/GBq (50 +/- 33 Gy) and 0.27 +/- 0.20 Gy/GBq (2.4 +/- 1.9 Gy), respectively. There was an acceptable rate of toxicity in 30% of grades I and II, respectively, and 10% with grade III. There was reversible in the most patients within 14 days after treatment. The response was assessed on CT: two patients had a partial response (PR), five patients had stable disease and three patients had disease progression. CONCLUSION: Treatment of colorectal liver metastases or HCC using high activities of (188)Re-microspheres was well tolerated and a PR was seen in 2 of 10 patients. The treatment represents a therapeutic option in these patients.

A comparative study of 188Re-HEDP, 186Re-HEDP, 153Sm-EDTMP and 89Sr in the treatment of painful skeletal metastases.

AIM: The surface bone-seeking radiopharmaceuticals 188Re-HEDP, 186Re-HEDP and 153Sm-EDTMP, and the volume seeker 89Sr were investigated to determine the efficacy and toxicity in pain palliation of bone metastases. METHOD: The effect of treatment with 188Re-HEDP, 186Re-HEDP, 153Sm-EDTMP and 89Sr on pain symptoms, quality of life, and bone marrow function were studied. In total, 79 patients (18 with breast cancer and 61 with prostate cancer) were treated (31 patients with 188Re-HEDP, 15 patients each with 186Re-HEDP and 153Sm-EDTMP, and 18 patients with 89Sr). All patients were interviewed using standardized sets of questions before and after therapy weekly for 12 weeks. Blood counts were taken weekly for 6 weeks and after 12 weeks. RESULTS: In total, 73% of patients reported pain relief (77% after 188Re-HEDP, 67% after 186Re-HEDP 73% after 153Sm-EDTMP, and 72% after 89Sr). Fifteen percent of patients could discontinue their analgesics and were pain-free. Pain showed a decrease from 3.6+/-1.7 to a maximum of 2.2+/-1.8 at visual analogue scale in 10 steps (P<0.01). Patients described an improvement on the Karnofsky performance scale from 70+/-10% to 78+/-14% 12 weeks after treatment (P=0.15). There were eight patients with a thrombocytopenia grade I, two patients with grade II and one with grade III. The maximum nadir of platelet and leukocyte counts were observed between the 2nd to 5th week after treatment and was reversible within 12 weeks. There were no significant differences in pain palliation, Karnofsky performance status (KPS) and bone marrow toxicity between the different radionuclides (P=0.087-0.449). CONCLUSION: All radiopharmaceuticals were effective in pain palliation, without induction of severe side effects or significant differences in therapeutic efficacy or toxicity.