Decreased serum E-selectin concentration after 89Sr-chloride therapy for metastatic prostate cancer bone pain

Palliative systemic radionuclide therapy with 89Sr-chloride is a useful intervention for patients with bone pain from metastatic prostatic cancer. Although this radionuclide is highly effective, its mechanism of action remains unresolved. This investigation sought to determine whether systemic radionuclide therapy decreases the production of cell adhesion molecules (E-selectins) that participate in the metastatic process.

Sera were collected from 25 men with metastatic (stage IV) prostate carcinoma who received 89Sr-chloride palliative therapy and from 10 age-matched healthy volunteers. The serum concentration of E-selectin was quantified by an enzyme-linked immunosorbent assay. Sera from 5 patients who received 2 courses of radionuclide therapy were also included in the analysis.

A 2.8-fold decrease in serum E-selectin concentration occurred within 2 mo of radionuclide therapy (P < 0.0001). At 10 mo, however, the concentration increased to a mean (+/- SD) of 151.2 +/- 51.3 ng/mL, surpassing the baseline concentration. This pattern coincided with symptomatic improvement and subsequent health status deterioration. For patients who received 2 courses of radionuclide therapy, a second fall in serum E-selectin concentration followed the second radionuclide treatment.

A significant decrease in serum E-selectin concentration was observed after systemic radionuclide therapy. This finding suggests that expression of cell adhesion molecules, an important determinant of metastatic progression, may be inhibited by 89Sr-chloride.