Objective: Retrospective comparative analysis of strontium-89 chloride (Sr89) and rhenium-186-hydroxyethylidene diphosphonate (Re186-HEDP) radionuclide treatment to find predictors of response in patients with painful metastases from hormone refractory prostate cancer.
Patients and methods: Clinical data from 60 hormone refractory PCA patients (i.e. rising PSA at castrate testosterone serum levels) was obtained. Twenty-nine were treated with Sr89, 31 were treated with Re186-HEDP for painful osseous metastasis. Response was defined as a patient-reported decrease in pain and/or reduction in pain medication with stable pain level. Hematological parameters and serum levels of PSA, alkaline phosphatase, and lactate dehydrogenase were assessed prior to and at 4-week intervals after treatment.
Results: Median survival of all patients was 7 months (95% CI: 6-9 months). Overall, 33/60 (55%) patients reported a decrease in pain after the first radionuclide treatment. This percentage was similar for patients treated with Re168-HEDP and Sr89. Mean duration of reported pain response was 75 days (+/- 68 days) for Sr89 and 61 days (+/- 56 days) for Re186-HEDP, which was not significantly different. A lower blood hemoglobin concentration was associated with a lower pain response rate. In a multivariate Cox regression analysis, pain response to radionuclide treatment predicted longer survival after treatment.
Conclusions: Pain response was present in 55% of patients. Serum hemoglobin concentration prior to radionuclide treatment predicted pain response for both Re186-HEDP and Sr89. A reduction in pain upon radionuclide treatment was associated with a longer survival after treatment.