Treatment of metastatic hormone-refractory prostate adenocarcinoma (MatLyLu) in Copenhagen rats with micro-osmotic interleukin-2 pumps

Background: We studied the influence of interleukin-2 (IL-2) therapy on tum or growth and prevention of metastasis in metastatic, hormone-refractory pr ostatic carcinoma (PCa) in an animal model orthotopically (ortho) and subcu taneously (sc). Materials and Methods: 75 juvenile male Copenhagen rats wer e divided into five groups of 15 rats each. MatLyLu-PCa (MLL) was implanted ortho (n=30) in 2 groups or sc (n=30) in 2 groups and were treated locally at the tumor site with micro-osmotic pumps. The rats in 2 groups received IL-2 pumps with 36 x 10(6) IU of IL-2 and the mts in 2 other groups were tr eated with pumps delivering albumin only as a control. The rats in the last group received ortho MLL and sc IL-2 (n=15). Survival time was then monito red. Results: Prostatic tumor was found in all or-the animals. Aditionally lymphogenic and pulmonary metastasis was found in all animals. The orthotop ic and sc IL-2-treated groups showed a statistically significantly increase d survival compared with the orthotopic and sc albumin-treated groups. When treating the ortho MLL with sc IL-2 there was still a statistically signif icant longer survival than in the control groups. Conclusion: IL-2 therapy significantly reduces tumor growth of rats with metastatic, hormone-refract ory prostatic cancer MatLyLu.