Systemic radionuclide therapy in pain palliation.

Several radiopharmaceuticals were investigated to determine their efficacy and toxicity in the palliation of painful bone metastases. Data on the influence of rhenium-188 hydroxyethylidene diphosphonate (188Re-HEDP), rhenium-186 hydroxyethylidene diphosphonate (186Re-HEDP), and strontium-89 (89Sr) on pain symptoms, quality of life, and bone-marrow function were obtained in 64 patients with breast and prostate cancer. Thirty-one patients were treated with 188Re-HEDP (3194 +/- 387 MBq), 15 patients with 186Re-HEDP (1358 +/- 158 MBq), and 18 patients with 89Sr (152 +/- 19 MBq). The 188Re-HEDP group included six breast cancer patients and 25 prostate cancer patients; the 186Re-HEDP group included three breast cancer patients and 12 prostate cancer patients; and the 89Sr group included three breast cancer patients and 15 prostate cancer patients. All subjects participated in an interview using a standardized sets of questions before and after the 12-week term of therapy. Blood counts were taken weekly for six weeks and after 12 weeks. Results showed that 77 percent of patients reported pain relief after treatment with 188Re-HEDP, 67 percent after treatment with 186Re-HEDP, and 72 percent after treatment with 89Sr. Sixteen percent of patients treated with 188Re-HEDP, 13 percent treated with 186Re-HEDP, and 17 percent treated with 89Sr were able to discontinue their analgesics and were pain-free. Patients described an improvement on Karnofsky performance status (KPS) from 73 +/- 7 percent to 85 +/- 8 percent 12 weeks after 188Re-HEDP (p < 0. 05), from 72 +/- 13 percent to 79 +/- 12 percent after 186Re-HEDP (p = 0.251), and from 62 +/- 14 percent to 69 +/- 16 percent after 89Sr (p = 0.415). Only three patients undergoing 188Re-HEDP therapy, one undergoing 186Re-HEDP therapy, and three undergoing 89Sr therapy had thrombocytopenia (platelet count below 100 x 10(3)/microl) following treatment. The maximum nadir of platelet and leukocyte counts was observed between the second and fifth week after treatment for all radionuclides and was reversible within 12 weeks. The nadir was earlier for 188Re-HEDP with a shorter physical half-life compared with 89Sr. There were no significant differences in bone marrow toxicity (p = 0.123-0.421). Results of this study indicate that all evaluated radiopharmaceuticals were effective in pain palliation without induction of severe side effects. The increase in KPS after 188Re-HEDP was the only statistically significant finding (p = 0.001).