Radionuclide therapy has proven to be an efficacious palliative treatment for metastatic prostate cancer. Its potential therapeutic possibilities may be substantially increased by combining it with effective radiosensitizing drugs. Methods: This study explores the radiosensitizing properties of cisplatin when combined with 186Re-labeled hydroxyethylidene diphosphonate (HEDP) in the treatment of R3327-MATLyLu prostate cancer cells in vitro. A concomitant incubation during 4 d, combining various concentrations of cisplatin (0, 0.42, 0.83 and 1.67μmol/L) and 186Re- HEDP (0, 1.84 and 3.69 MBq/mL [0, 50 and 100 μCi/mL, respectively]) was followed by the determination of the cell numbers surviving and the replating of these cells in semisolid agar. Results: The surviving fraction of clonogenic tumor cells after combination treatment clearly showed synergism when analyzed by a panel of three different published analytical methods. In addition, analysis of variance demonstrated a significant interaction between radionuclide therapy and cisplatin-based chemotherapy (P < 0.001). Treatment with 186Re-HEDP and cisplatin by sequential incubation yielded similar, but never superior results. Conclusion: It is concluded that radionuclide therapy in combination with cisplatin is able, in principle, to improve therapeutic success rate in metastatic prostate cancer in a more than additive way.
|Number of pages||5|
|Journal||Journal of Nuclear Medicine|
|Publication status||Published - 1 Apr 1999|