II trattamento con Metastron delle metastasi ossee da carcinoma prostatico: bilancio effettivo

Introduction. Radiometabolic therapy is used alongside external radiotherapy in treating prostate cancer with bone metastasis. The most commonly used radionuclide is Strontium-89, which imitates the behaviour of calcium in the body and therefore localises in those areas where the calcium turnover has increased - such as in bone metastases - and where it is withheld. Materials and methods. Between January '96 and December '98, 20 patients with painful multiple bone metastases already being treated with analgesics, were given a single standard dose of 150 MBq of the radioisotope without requiring admittance to protected sections or collection of radioactive urine. The pain was assessed by the visual analog scale and patient data were collected on special charts prior to the radiometabolic treatment (basic chart) and during follow-up (follow-up chart) at 1, 3, 6 and more months. Results. the response took into consideration the amount of pain and any reduction in the analgesics and was classified as nil in 19%, slight in 23%, good in 35% and excellent in 23%. Average duration of the response was 6 months; 7 patients were treated again with reduction in symptoms. Toxicity, due basically to medullar depression and evaluated according to W.H.O. parameters, was limited and consisted mostly of platelet disorder and to a lesser extent leukopenia. Grade II toxicity was noted in 7% of first treatments and 15% of re-treatments. Conclusions. It may be confirmed that radiometabolic therapy proved effective (good + excellent response) in 58% of the cases as well as moderately toxic and easy to perform. The future could see the therapy used in earlier stages of the disease, with less extensive or pre-symptomatic bone metastases, and the possibility of an association with radiosensitising drugs (e.g. low-dose platinum) or the use of new radioisotopes (e.g. Samario-153).