This study aims to develop a new agent, the ³²P-
chromic phosphate-
poly(l-lactide) (³²P-CP-PLLA) seed and to explore its anticancer effect against
prostate cancer (Pca) with local
lymphatic metastasis in nude mice. ³²P-CP-PLLA seeds of sustained release and nude mouse models of Pca with
lymphatic metastasis were prepared. After 4 weeks, the
tumor nude mouse models were randomly assigned into five groups. ³²P-CP-PLLA seeds (3.7, 7.4, 14.8, and 0 MBq) and ³²P-
CP (14.8 MBq) were implanted in the
tumor tissues of the nude mouse models. The following were discussed in this study: (1) the distributions of ³²P-CP-PLLA, (2) the pathological and morphological changes in the
tumor and regional lymph nodes, and (3) the changes in white blood cell (WBC) and platelet counts in peripheral blood for toxic reactions. The homemade ³²P-CP-PLLA seed was a regular green cylinder, with an even distribution of mass and radioactivity. After implantation, single-photon emission computed tomograph (SPECT) showed that ³²P was mainly gathered in the
tumor and regional lymph nodes. Morphological examinations revealed that
necrosis and
hemorrhage were around the
tumor and focal lymph nodes. The
tumor inhibition rates of the five groups were 70.16% ± 5.48%, 80.18% ± 5.84%, 84.97% ± 4.79%, (-), and 78.81% ± 3.13%, respectively. These values were all positive when compared with the control group. As a new homemade agent of pure β-ray, local implantation of the agent increased the focal retention of radioactivity at the target. Moreover, effective half-life showed an obvious damage to the
tumor and metastatic foci of Pca.