188Re—HEDP治疗肿瘤骨转移痛药代动力学研究

目的研究188Re标记的1-羟基-1,1-二膦酸钠乙烷（即依替膦酸盐,HEDP）在肿瘤骨转移患者体内的分布和排泄,分析不同剂量188Re—HEDP在患者体内的药代动力学特点。方法将40例肿瘤骨转移患者分为4组,每组10例,4组分别按体质量“弹丸”式经肘静脉注射188Re—HEDP20,30,40和50MBq／kg,给药时及给药后1,2,4,5,12,24,36,48,60和72h分别用SPECT仪采集胸前区和前后位、后前位全身图像,并收集患者尿液,测量放射性。利用感兴趣区（ROI）技术在左心室区测得经本底校正的放射性,作为血液放射性。将1h全身前位、后位放射性总计数率经死时间和时间衰减校正后的几何平均值设定为100％注射剂量（ID）,据此估算上述各时间点全身和各器官的百分注射剂量率（％ID）。各组间的计量资料采用元、中位数、范围等表示,组间比较采用方差分析或t检验。结果20～50MBq／kg范围内,188Re—HEDP在体内的时间-放射性曲线下面积（AUC）与其剂量呈线性关系,r^2=0．9376。4组均符合静脉给药二室模型,AUC值中位数分别为3．32×10^5,3．97×10^5,7．83×10^5,8．58×10^5;分布速度常数（α值）中位数分别为0．06,0．05,0．04,0．06;消除速度常数（B值）中位数分别为1．16×10^-3,1．16×10^-3,1．03×10^-3,1．15×10^-3;指数项系数A值中位数分别为3591．21,4858．23,5642．48,4167．05;指数项系数B值中位数分别为293．97,352．95,614．41,1063．82;药物分布相半衰期T1/2值中位数分别为12．51,12．83,15．41,12．02min;药物消除相半衰期T1／2（β）中位数分别为595．47,596．50,673．09,600．93min。骨组织是摄取188Re—HEDP的主要组织,给药后4h放射性摄取高,约为40％ID,其他组织未见明显摄取188Re—HEDP0188Re．HEDP主要通过泌尿系统排泄,给药后24h排出66．79％ID,其中74％在给药后5h内排出。结论20～50MBq／kg范围内,188Re—HEDP在机体内的药代动力学符合血管给药二室模型。188Re—HEDP T1/2（β）平均为616．50min。188Re—HEDP主要通过泌尿系统排泄;骨组织是摄取188Re—HEDP的主要组织。     

肿瘤骨转移疼痛患者对188Re-HEDP的耐受性研究

Objective To study the tolerance to 188Re-1-hydroxy-1 ,1-ethylidene disodium phosphonate(HEDP) in patients with bone pain caused by osseous metastases. Methods Thirty-one patients(10with prostate cancer, 9 with breast cancer, 3 with lung cancer, 5 with liver cancer, 2 with rectal cancer, 1with esophageal cancer and 1 with renal cancer) received a single injection dose of 188Re-HEDP. The patients were divided into four groups according to the injection dose: 20 MBq/kg (6 patients), 30 MBq/kg(6 patients), 40 MBq/kg (9 patients), and 50 MBq/kg (10 patients). Haematological toxicity (WHO grading) of grade Ⅲ- Ⅳ was considered unacceptable. Vital signs and adverse effects after injection were recorded for 8 weeks. Blood counts were measured weekly during a period of 8 weeks. Biochemical parameters and electrocardiogram were assayed at week 4 and 8. Statistical analysis was performed for per-protocol (pp) population (t-test). Results Twenty-seven patients belonged to PP population with 5 in the group of 20 MBq/kg, 5 in the group of 30 MBq/kg, 8 in the group of 40 MBq/kg and 9 in the group of 50 MBq/kg.No obvious adverse effects and no significant change of vital signs, electrocardiogram, liver and renal function were found after injection. Alkaline phosphatase was slightly higher than baseline at week 4 and 8 after therapy, but the difference was not statistically significant. In the 20 MBq/kg group, reversible grade Ⅰ leucopenia was noted in 1 patient. In the 30 MBq/kg group, 2 patients showed reversible grade Ⅰ leucopenia including 1 alone with reversible grade Ⅲ thrombopenia. In the 40 MBq/kg group, reversible grade Ⅰ leucopenia and thrombopenia was observed in 1 patient and reversible grade Ⅱ leucopenia and thrombopenia in another patient. In the .50 MBq/kg group, 3 patients showed reversible grade Ⅱ leucopenia. The lowest level of thrombopenia was at week 4(143.5 × 109/L), leucopenia at week 6 (5.4 × 109/L) and anaemia at week 8(t = 3.1325, 3.3156, 3.4917, all P ＜ 0. 05 compared with baseline). At week 8, the mean level of platelet and leucocyte recovered to baseline. "Bounce pain" was found in 2 of 27 patients (7.41%).Conclusions The dose of 20 MBq/kg, 30 MBq/kg, 40 MBq/kg or 50 MBq/kg of 188Re-HEDP do not cause significant side effects on cancer patients with bone metastases, though there is a tendency that the haematological toxicity may increase as the dose of 188Re-HEDP increases.     

肿瘤骨转移疼痛患者对^188Re-HEDP的耐受性研究

目的 评价^188Re-1-羟基-1,1-二膦酸钠乙烷（即依替膦酸盐,HEDP）治疗肿瘤骨转移疼痛患者的安全性.方法 符合入选标准的31例患者（前列腺癌10例,乳腺癌9例,肺癌3例,肝癌5例,直肠癌2例,食管癌1例,肾癌1例,均随时间顺序人选）知情同意后接受了按体质量肘静脉单次注射^188ReHEDP,据药物递增剂量分为4个组：20 MBq/kg组6例、30 MBq/kg组6例、40 MBq/kg组9例、50 MBq/kg组10例.低剂量组安全性分析结束并显示安全后,才开始下一剂量组试验.如果患者出现由于用药引起的不可耐受的、WHO公布的Ⅲ或Ⅳ级骨髓毒性,即终止剂量递增,并认为前一组剂量为最大可接受剂量.观察指标包括给药前及给药后8周内每例患者的生命体征（用药后1,6,12,24,48,72 h和1,2,3,4,6,8周）,血细胞计数（用药后1,2,3,4,6和8周）,心电图,肝、肾功能,ALP（用药后4,8周）,＂反跳痛＂以及不良反应等.统计分析主要针对符合方案集（PP）人群,包括统计描述和统计推断（t检验）.结果 31例患者中有27例属于PP人群：20 MBq/kg组5例、30 MBq/kg组5例、40 MBq/kg组8例、50 MBq/kg组9例.在受试剂量范围内,没有观察到188Re-HEDP对患者生命体征、心电图、肝肾功能和ALP的不良影响.20 MBq/kg组的5例患者中仅1例自细胞出现WHO Ⅰ级毒性;30 MBq/kg组5例患者中2例白细胞出现WHO Ⅰ级毒性,其中1例合并血小板Ⅲ级毒性,但给药后8周白细胞和血小板均恢复正常;40 MBq/kg组8例患者中2例白细胞和血小板同时出现毒性反应,分别为WHO Ⅰ级和Ⅱ级,表现为白细胞和血小板同时、同级减低;50 MBq/kg组9例患者中3例白细胞出现WHOⅡ级毒性.全部患者的血小板均在给药后4周达最低水平,平均为143.5×109/L;白细胞均在给药后6周达最低水平,平均为5.4×109/L（两者与给药前基线值比较,t值分别为3.1325和3.3156,P均＜0.05）,给药后8周自细胞和血小板均恢复到基线水平;而血红蛋白在给药后8周最低（与基线值比较,t值为3.4917,P＜0.05）.PP人群27例中有2例出现＂反跳痛＂,发生率7.41%（2/27）.结论 按体质量注射188Re-HEDP 20,30,40和50 MBq/kg对肿瘤骨转移患者均无明显毒性及不良反应,且随着用药剂量增加,188Re-HEDP对骨髓的抑制有增加趋势.     

Re-186(Sn) HEDP for treatment of painful osseous metastases: initial clinical experience in 20 patients with hormone-resistant prostate cancer.

Rhenium-186(tin) hydroxyethylidene diphosphonate (HEDP) is a new radiopharmaceutical that localizes in areas of osseous metastases in a manner similar to that of standard bone-scanning agents. It also emits beta particles with sufficient energy to be therapeutically useful. A single intravenous injection of about 33 mCi (1,221 MBq) was given to each of 20 elderly patients with advanced skeletal metastases from hormonally resistant prostate cancer. Prompt, significant relief of pain occurred 80% of the time with no significant side effects and only minimal, transient marrow toxicity. Re-186(Sn) HEDP appears to be a useful new agent for the palliation of painful osseous metastases in prostate cancer.     

186Re-HEDP for metastatic bone pain in breast cancer patients

Two-thirds of patients with metastatic cancer suffer from pain. Pain originating from skeletal metastases is the most common form of cancer-related pain. Bone pain, often exacerbated by pressure or movement, limits the patient's autonomy and social life. Pain palliation with bone-seeking radiopharmaceuticals has proven to be an effective treatment modality in patients with metastatic bone pain. These bone-seeking radiopharmaceuticals are extremely powerful in treating scattered painful bone metastases, for which external beam radiotherapy is impossible because of the large field of irradiation. (186)Re-hydroxyethylidene diphosphonate (HEDP) is a potentially useful radiopharmaceutical for this purpose, having numerous advantageous characteristics. Bone marrow toxicity is limited and reversible, which makes repetitive treatment safe. Studies have shown encouraging clinical results of palliative therapy using (186)Re-HEDP, with an overall response rate of ca. 70% in painful bone metastases. It is effective for fast palliation of painful bone metastases from various tumours and the effect tends to last longer if patients are treated early in the course of their disease. (186)Re-HEDP is at least as effective in breast cancer patients with painful bone metastases as in patients with metastatic prostate cancer. It is to be preferred to radiopharmaceuticals with a long physical half-life in this group of patients, who tend to have more extensive haematological toxicity since they have frequently been pretreated with bone marrow suppressive chemotherapy. This systemic form of radionuclide therapy is simple to administer and complements other treatment options. It has been associated with marked pain reduction, improved mobility in many patients, reduced dependence on analgesics, and improved performance status and quality of life.     

Rhenium-186 hydroxyethylidene diphosphonate for the treatment of painful osseous metastases.

Rhenium-186 (tin)hydroxyethylidene diphosphonate (HEDP) is a new radiopharmaceutical that localizes in skeletal metastases in patients with advanced cancer. A single intravenous administration of approximately 34 mCi (1,258 MBq) resulted in significant improvement in pain in 33 of 43 evaluable patients (77%) following the initial injection, and in 7 of 14 evaluable patients (50%) following a second treatment. Patients responding to treatment experienced an average decrease in pain of about 60%, with one in five treatments resulting in a complete resolution of pain. The only adverse clinical reaction was the occurrence after about 10% of the administered doses of a mild, transient increase in pain within a few days following injection. Statistically significant but clinically unimportant decreases in total white blood cell counts and total platelet counts were observed within the first 8 weeks following the injection; no other toxicity was apparent. Rhenium-186(Sn)HEDP is a useful new compound for the palliation of painful skeletal metastases.     

A phase 2 study of high-activity 186Re-HEDP with autologous peripheral blood stem cell transplant in progressive hormone-refractory prostate cancer metastatic to bone

Purpose We investigated the potential for improvement in disease control by use of autologous peripheral blood stem cell transplant (PBSCT) to permit administration of high activities of ¹⁸⁶Re-hydroxyethylidene diphosphonate (HEDP) in patients with progressive hormone-refractory prostate cancer (HRPC). Methods Eligible patients had progressive HRPC metastatic to bone, good performance status and minimal soft tissue disease. Patients received 5,000 MBq of ¹⁸⁶Re-HEDP i.v., followed 14 days later by PBSCT. Response was assessed using PSA, survival, pain scores and quality of life. Results Thirty-eight patients with a median age of 67 years (range 50–77) and a median PSA of 57 ng/ml (range 4–3,628) received a median activity of 4,978 MBq ¹⁸⁶Re-HEDP (range 4,770–5,100 MBq). The most serious toxicity was short-lived grade 3 thrombocytopenia in 8 (21%) patients. The median survival of the group is 21 months (95%CI 18–24 months) with Kaplan-Meier estimated 1- and 2-year survival rates of 83% and 40% respectively. Thirty-one patients (81%, 95% CI 66–90%) had stable or reduced PSA levels 3 months post therapy while 11 (29%, 95% CI 15–49%) had PSA reductions of >50% lasting >4 weeks. Quality of life measures were stable or improved in 27 (66%) at 3 months. Conclusion We have shown that it is feasible and safe to deliver high-activity radioisotope therapy with PBSCT to men with metastatic HRPC. Response rates and survival data are encouraging; however, further research is needed to define optimal role of this treatment approach.     

186Re-etidronate. Efficacy of palliative radionuclide therapy for painful bone metastases.

Pain palliation with bone-seeking radiopharmaceuticals is an effective treatment modality in patients with advanced metastatic bone cancer. Several studies have shown encouraging clinical results of palliative therapy using 186Re-HEDP, with an overall reported response rate of +/-71% for painful osseous metastasized prostate and breast cancer patients. 186Re-HEDP is a very potential isotope with numerous advantageous characteristics for this purpose. Myelosuppressive toxicity is limited and reversible, which makes repetitive treatment safe. However, individual studies are difficult to compare, and are hampered by the numerous and different methods used to assess clinical response. Standardized clinical response assessment using the objective multi-dimensional pain evaluation model should therefore be implemented.     

Evaluation of toxicity and efficacy of 186Re-hydroxyethylidene diphosphonate in patients with painful bone metastases of prostate or breast cancer.

Twenty-eight patients (12 men with prostate cancer, 16 women with breast cancer) were included in a phase II trial to evaluate the efficacy of 186Re-hydroxyethylidene diphosphonate (HEDP) on pain from bone metastasis and the toxicity of this agent. METHODS: After intravenous administration of 1295 MBq 186Re-HEDP, the efficacy was evaluated by means of a daily log. RESULTS: We observed an objective response in 67% of prostate cancer patients and in 36% of breast cancer patients. The mean duration of response was 45 d for prostate cancer patients and 24 d for breast cancer patients. No major adverse effects were observed. Marrow toxicity did not exceed grade 2 for white blood cells and grade 3 for platelets using National Cancer Institute criteria. CONCLUSION: 186Re-HEDP provides safe symptomatic relief of pain in prostate cancer patients. The benefit of this treatment is less clear in breast cancer patients. Further studies should be conducted to evaluate treatment by 186Re-HEDP at an earlier stage of the disease.     

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.     

Combination 186Re-HEDP and cisplatin supra-additive treatment effects in prostate cancer cells.

Radionuclide therapy has proven to be an efficacious palliative treatment for metastatic prostate cancer. Its potential therapeutic possibilities may be substantially increased by combining it with effective radiosensitizing drugs. METHODS: This study explores the radiosensitizing properties of cisplatin when combined with 186Re-labeled hydroxyethylidene diphosphonate (HEDP) in the treatment of R3327-MATLyLu prostate cancer cells in vitro. A concomitant incubation during 4 d, combining various concentrations of cisplatin (0, 0.42, 0.83 and 1.67 micromol/L) and 186Re-HEDP (0, 1.84 and 3.69 MBq/mL [0, 50 and 100 microCi/mL, respectively]) was followed by the determination of the cell numbers surviving and the replating of these cells in semisolid agar. RESULTS: The surviving fraction of clonogenic tumor cells after combination treatment clearly showed synergism when analyzed by a panel of three different published analytical methods. In addition, analysis of variance demonstrated a significant interaction between radionuclide therapy and cisplatin-based chemotherapy (P < 0.001). Treatment with 186Re-HEDP and cisplatin by sequential incubation yielded similar, but never superior results. CONCLUSION: It is concluded that radionuclide therapy in combination with cisplatin is able, in principle, to improve therapeutic success rate in metastatic prostate cancer in a more than additive way.     

Combined use of zoledronic acid and 153Sm-EDTMP in hormone-refractory prostate cancer patients with bone metastases

Purpose

¹⁵³Sm-ethylenediaminetetramethylenephosphonic acid (EDTMP; Quadramet®) is indicated for the treatment of painful bone metastases, whereas zoledronic acid (Zometa®) is indicated for the prevention of skeletal complications. Because of the different therapeutic effects, combining the treatments may be beneficial. Both, however, accumulate in areas with increased osteoblastic activity. Possible drug interactions were investigated.

Methods

Patients with hormone-refractory prostate cancer were treated with 18.5 MBq/kg ¹⁵³Sm-EDTMP in weeks 1 and 3 and with 37 MBq/kg in week 15. Treatment with 4 mg zoledronic acid began in week 3 and continued every 4 weeks through week 23. In weeks 3 and 15, zoledronic acid was administered 2 days before ¹⁵³Sm-EDTMP treatment. Urine was collected 48 h after injection of ¹⁵³Sm-EDTMP, and whole-body images were obtained 6, 24 and 48 h post-injection. The effect of zoledronic acid on total bone uptake of ¹⁵³Sm-EDTMP was measured indirectly by the cumulative activity excreted in the urine in weeks 1, 3 and 15. Biodistribution, safety, tolerability and effect on prostate-specific antigen level were also studied.

Results

The urinary excretion in week 3 divided by the urinary excretion in week 1 (baseline) times 100% was mean 98.4?±?11.6% (median 96.2%). From week 1 to 15, after four zoledronic acid treatments, the mean ratio was 101.9?±?10.7% (median 101.8%). Bioequivalence could be concluded by using a two-sample t test for both per-protocol (n?=?13) and full-analysis sets (n?=?18). Toxicity was comparable to of monotherapy with ¹⁵³Sm-EDTMP.

Conclusion

Zoledronic acid treatment does not influence ¹⁵³Sm-EDTMP skeletal uptake. Combined treatment is feasible and safe.

     

186Re-HEDP in the treatment of patients with inoperable osteosarcoma.

The aim of this study was to examine the safety and efficacy of (186)Re-hydroxyethylidene diphosphonate (HEDP) as an adjuvant to external-beam radiotherapy (EBRT) in the treatment of patients with osteosarcoma. METHODS: Thirteen patients (9 male, 4 female; age range, 12-42 y) were treated with combination chemotherapy (standard U.K. protocol) and (186)Re-HEDP therapy (18.5 MBq/kg, intravenously), followed by EBRT. A full blood count; liver function test; and measurements of urea and electrolytes, glomerular filtration rate, and left ventricular function were performed on all patients before and after therapy. Tumor volume and composition were obtained from CT or MRI data. Dosimetric calculations were performed using the MIRD formalism. RESULTS: Of the 13 patients, 1 is still under follow-up. The median survival time was 36 mo (range, 12-216 mo) from diagnosis and 5 mo (range, 1-60 mo) from the last (186)Re-HEDP treatment. The mean tumor dose delivered with (186)Re-HEDP was calculated to be 5.8 Gy (range, 0.5-16 Gy). CT and MRI revealed the tumors to have a complex structure, comprising "ossified," "partially calcified," and "soft-tissue" components. Posttherapy scans showed a heterogeneous distribution of (186)Re-HEDP in the tumor mass: Although the "soft-tissue" component showed minimal uptake of the therapeutic dose, the "ossified component" showed intense uptake. The 3 long-term survivors in whom tumor sterilization was achieved received calculated mean tumor doses in the range of 2.0-3.1 Gy, which was believed to be an underestimate of the actual tumor doses delivered. CONCLUSION: This study indicates that a simple approach to tumor dosimetry based on mean tumor dose is inappropriate because it may underestimate the dose delivered to these heterogeneous tumors. The data also indicate that EBRT combined with a standard dose of 18.5 MBq/kg of (186)Re-HEDP does not provide a sufficient dose to achieve tumor sterilization. A dose estimation technique is required that is based on the determination of tumor dose at the individual voxel level and that is able to represent the heterogeneous uptake observed in these complex tumor structures with highly nonuniform composition. This, coupled with individualized dose escalation, may then achieve the goal of tumor sterilization.     

<Superscript>188</Superscript>Re-HEDP combined with capecitabine in hormone-refractory prostate cancer patients with bone metastases: a phase I safety and toxicity study

Purpose

¹⁸⁸Re-HEDP is indicated for the treatment of pain in patients with painful osteoblastic bone metastases, including hormone-refractory prostate cancer patients. Efficacy may be improved by adding chemotherapy to the treatment regimen as a radiation sensitizer. The combination of ¹⁸⁸Re-HEDP and capecitabine (Xeloda®) was tested in a clinical phase I study.

Methods

Patients with hormone-refractory prostate cancer were treated with capecitabine for 14 days (oral twice daily in a dose escalation regimen with steps of 1/3 of 2,500 mg/m² per day in cohorts of three to six patients, depending on toxicity). Two days later patients were treated with 37 MBq/kg ¹⁸⁸Re-HEDP as an intravenous injection. Six hours after treatment post-therapy scintigraphy was performed. Urine was collected for 8 h post-injection. Follow-up was at least 8 weeks. The primary end-point was to establish the maximum tolerable dose (MTD) of capecitabine when combined with ¹⁸⁸Re-HEDP. Secondary end-points included the effect of capecitabine on the biodistribution and pharmacokinetics of ¹⁸⁸Re-HEDP.

Results

Three patients were treated in the first and second cohorts, each without unacceptable toxicity. One of six patients in the highest cohort experienced unacceptable toxicity (grade 4 thrombopaenia). The MTD proved to be the maximum dose of 2,500 mg/m² per day capecitabine. No unexpected toxicity occurred. Capecitabine had no effect on uptake or excretion of ¹⁸⁸Re-HEDP.

Conclusion

Capecitabine may be safely used in combination with ¹⁸⁸Re-HEDP in a dose of 2,500 mg/m² per day and 37 MBq/kg, respectively. Efficacy will be further studied in a phase II study using these dosages.

     

A multicentre observational study of radionuclide therapy in patients with painful bone metastases of prostate cancer

A multicentre observational study was conducted by the Italian Association of Nuclear Medicine between 1996 and 1998. Twenty-nine Nuclear Medicine Departments participated. The aims of the study were to systematically evaluate the efficacy, toxicity and repeatability of radionuclide therapy of painful bone metastases (RTBM) in a large number of patients and to assess its incidence in patients with prostate cancer. Out of 818 treatments performed with a single i.v. dose of 148 MBq of strontium-89 chloride or 1,295 MBq of rhenium-186 hydroxyethylidene diphosphonate (HEDP), 610 could be evaluated (527 with ⁸⁹Sr and 83 with ¹⁸⁶Re-HEDP). Eighty-one patients received multiple (up to five) RTBM. The total number of retreatments was 100. Patients were followed up for a period of 3-24 months. Results, assessed according to pain relief and consumption of analgesic drugs, were expressed at four levels: 1, no response; 2, mild response; 3, good response; 4, excellent response. Responses were: level 1 in 19%, level 2 in 21.3%, level 3 in 33.3% and level 4 in 26.4% of cases. Retreatments showed significantly (P<0.01) worse responses (48% levels 3+4), in comparison to first RTBM. Duration of palliation was 5.0Dž.5 months, and was longer in cases of excellent response, in first RTBM, in patients with limited metastases and when ⁸⁹Sr was used. Better responses were found in cases of limited skeletal disease, under good clinical conditions, when life expectancy exceeded 3 months, and in radiologically osteoblastic or mixed bone lesions. The only statistically significant predictive factor was life expectancy (P<0.001). Flare phenomenon (14.1% of cases) did not correlate with the response. Haematological toxicity (mild to moderate in most cases) mainly affected platelets, and was observed in 25.5% of cases overall and in 38.9% of retreatments. RTBM did not seem to prolong life, though in some cases scintigraphic regression of bone metastases was observed. The two radiopharmaceuticals did not show any statistically significant differences in palliative efficacy and toxicity, either in first RTBM or in retreatments.     

A multicentre observational study of radionuclide therapy in patients with painful bone metastases of prostate cancer

A multicentre observational study was conducted by the Italian Association of Nuclear Medicine between 1996 and 1998. Twenty-nine Nuclear Medicine Departments participated. The aims of the study were to systematically evaluate the efficacy, toxicity and repeatability of radionuclide therapy of painful bone metastases (RTBM) in a large number of patients and to assess its incidence in patients with prostate cancer. Out of 818 treatments performed with a single i.v. dose of 148 MBq of strontium-89 chloride or 1,295 MBq of rhenium-186 hydroxyethylidene diphosphonate (HEDP), 610 could be evaluated (527 with 89Sr and 83 with 186Re-HEDP). Eighty-one patients received multiple (up to five) RTBM. The total number of retreatments was 100. Patients were followed up for a period of 3-24 months. Results, assessed according to pain relief and consumption of analgesic drugs, were expressed at four levels: 1, no response; 2, mild response; 3, good response; 4, excellent response. Responses were: level 1 in 19%, level 2 in 21.3%, level 3 in 33.3% and level 4 in 26.4% of cases. Retreatments showed significantly (P<0.01) worse responses (48% levels 3+4), in comparison to first RTBM. Duration of palliation was 5.0+/-3.5 months, and was longer in cases of excellent response, in first RTBM, in patients with limited metastases and when 89Sr was used. Better responses were found in cases of limited skeletal disease, under good clinical conditions, when life expectancy exceeded 3 months, and in radiologically osteoblastic or mixed bone lesions. The only statistically significant predictive factor was life expectancy (P<0.001). Flare phenomenon (14.1% of cases) did not correlate with the response. Haematological toxicity (mild to moderate in most cases) mainly affected platelets, and was observed in 25.5% of cases overall and in 38.9% of retreatments. RTBM did not seem to prolong life, though in some cases scintigraphic regression of bone metastases was observed. The two radiopharmaceuticals did not show any statistically significant differences in palliative efficacy and toxicity, either in first RTBM or in retreatments.