Radionuclide therapy for painful bone metastases. An Italian multicentre observational study. Writing Committee of an...

It has been affirmed that observational studies give analogous results to randomised controlled ones.

A multicentre observational trial was conducted between 1996-1998 in order to evaluate the efficacy of palliative radionuclide therapy for bone metastases in a large number of patients. An evaluation was made on 510 patients with prostate cancer and painful bone metastases, treated with a single iv. dose of 89Sr-chloride (527 treatments) or 186Re-HEDP (83 treatments), in 29 Italian Nuclear Medicine Departments. Eighty-one patients received up to five injections, totalling 100 retreatments. Patients were followed up for a period of 3 months-2 years. Results were expressed at four levels of response: excellent, good, mild, and nil.

Responses were excellent in 26.4%, good in 33.3%, mild in 21.3% and nil in 19% of all treatments, while good and excellent responses were obtained in 48% of retreatments. No statistically significant correlations were found between response and age of patients, skeletal extension of tumour, pretherapeutic PSA levels, evidence of non-bony metastases, previous chemotherapy and/or external-beam radiotherapy; osteolytic lesions responded worse than osteoblastic or mixed ones. Hematological toxicity (mild to moderate), mainly affecting platelets, was observed in 25.5% of all treatments and in 38.9% of retreatments. No clear differences were found between the two radiopharmaceuticals employed.

Bearing in mind that observational studies can provide just as accurate results as randomised controlled trials, this study confirms the main findings of various limited monocentre trials.