Short- and long-term effects of Re-186-1,1-hydroxyethylidene diphosphonatein the treatment of painful bone metastases

This study evaluates the short- and long-term therapeutic efficacy of Re-18 6-1,1-hydroxyethylidene diphosphonate (HEDP) in the palliation of painful b one metastases and the influence of variables before therapy in determining the characteristics of pain palliation. Methods: Sixty patients with painf ul bone metastases from different tumor types were treated with 1406 MBq Re -186-HEDP. After treatment, the patients were followed up clinically at wee kly intervals for the first month and monthly thereafter up to 1 y, until d eath or pain relapse. Pain response was graded as complete, partial, minima l, or absent using the Wisconsin test scoring system. Duration of pain reli ef, performance status, tumor markers, serum alkaline phosphatase levels, h ematologic toxicity, and metastatic bone progression were also evaluated. R esults: Overall, 80% of individuals experienced prompt relief of pain, with 31% complete, 34% partial, and 15% minimal responses. Transient World Heal th Organization grade 1-2 hematologic toxicity was apparent, with a decreas e in the mean platelet (32%) and mean leukocyte (18%) counts at 3 and 4 wk, respectively. The degree of pain response did not correlate with any pretr eatment variable. The duration of pain relief ranged from 3 wk to 12 mo and correlated positively with the degree of response (P = 0.02) and negativel y with pretreatment scintigraphic scores and alkaline phosphatase levels (P = 0.02). Conclusion: Re-186-HEDP is effective for fast palliation of painf ul bone metastases from various tumors. The effect tends to last longer if patients are treated early in the course of their disease.