Palliative analgesic effect of Re-186HEDP in various cancer patients with bone metastases

The clinical picture of bone metastases is manifested by pain and loss of m echanical stability. Standard treatment options for bone metastases include external beam radiotherapy and the use of analgesics. Due to a large numbe r of lesions in many patients, the use of radionuclide therapy with beta em itters may be preferable. Re-186 hydroxyethylidene diphosphonate (Re-186 HE DP) is one of the radiopharmaceuticals suitable for palliative treatment of metastatic bone pain. The aim of this study was to investigate palliative and side effects of Re-186 HEDP in patients with different types of cancers . Material & Method Thirty one (17 male, 14 female) patients with various c ancers (10 prostate, 10 breast, 4 rectum, 5 lung, 2 nasopharynx) and bone m etastases were included in the study. Therapy was started with a fixed dose of 1295 MBq of Re-186 HEDP. If necessary, the same dose was repeated at le ast 3 times after an interval of 10-12 weeks; A total of 40 standard doses were given; 6 patients received repeated doses (3 doses in 3 patients, 2 do ses in 3 patients). The patients with bone marrow suppression were excluded from the study. The pain relief was assessed the Eastern Cooperative Oncol ogic Group (ECOC;) and the Karnofsky status index. All patients were evalua ted with standard evaluation forms filled in daily for a maximum of 10 week s. Results: The mean response rate was 87.5% in patients with breast and pr ostate cancer, 75% in patients with rectum cancer and 20% in patients with lung cancer. The overall response rate was 67.5%. The palliation period var ied between 6 and 10 weeks, with a mean of 8.1 +/- 1.3 weeks. The maximal p alliation effect was observed between the 3rd and 7th weeks. No serious sid e effects were seen except mild hematologic toxicity. Discussion & Conclusi on: It is concluded that Re-186 HEDP is a highly effective agent in the pal liation of metastatic bone pain in patients with prostate, breast and rectu m cancer, but not effective in lung cancer. On the other hand, Re-186 seems to be a good alternative to Sr-89 because of its preferable physical chara cteristics (such as short half life and gamma energy emission), low side ef fect profile, early response and repeatability.