A multicentre observational study of radionuclide therapy in patients withpainful 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 Dep artments participated. The aims of the study were to systematically evaluat e the efficacy, toxicity and repeatability of radionuclide therapy of painf ul bone metastases (RTBM) in a large number of patients and to assess its i ncidence in patients with prostate cancer. Out of 818 treatments performed with a single Lv. dose of 148 MBq of strontium-89 chloride or 1,295 MBq of rhenium-186 hydroxyethylidene diphosphonate (HEDP), 610 could be evaluated (527 with Sr-89 and 83 with Re-186-HEDP). Eighty-one patients received mult iple (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 t o pain relief and consumption of analgesic drugs, were expressed at four le vels: 1, no response; 2, mild response; 3, good response; 4, excellent resp onse. Responses were: level 1 in 19%, level 2 in 21.3%, level 3 in 33.3% an d level 4 in 26.4% of cases. Retreatments showed significantly (P <0.01) wo rse responses (48% levels 3+4), in comparison to first RTBM. Duration of pa lliation was 5.0 +/-3.5 months, and was longer in cases of excellent respon se, in first RTBM, in patients with limited metastases and when Sr-89 was u sed. Better responses were found in cases of limited skeletal disease, unde r good clinical conditions, when life expectancy exceeded 3 months, and in radiologically osteoblastic or mixed bone lesions. The only statistically s ignificant predictive factor was life expectancy (P <0.001). Flare phenomen on (14.1% of cases) did not correlate with the response. Haematological tox icity (mild to moderate in most cases) mainly affected platelets, and was o bserved in 25.5% of cases overall and in 38.9% of retreatments. RTBM did no t seem to prolong life, though in some cases scintigraphic regression of bo ne metastases was observed. The two radiopharmaceuticals did not show any s tatistically significant differences in palliative efficacy and toxicity, e ither in first RTBM or in retreatments.