Intratumoral injection of 32P-chromic phosphate in the treatment of implanted pancreatic carcinoma.

AIM: The aim of this study was to observe the biological distribution and anticancer effect of (32)P-chromic phosphate colloid (Cr(32)PO(4), (32)P-CP) after intratumoral injection to Pc-3 human pancreatic carcinoma-bearing nude mice. METHODS: Eighty-four (84) BALB/c nude mice with transplanted tumor were allocated to 11 groups. Groups 1-5 (n = 6) were intratumorally injected with 14.8 MBq of (32)P-CP and sacrificed at 2, 24, 48, 72, and 168 hours, respectively. Groups 6-11 (n = 9) received injections of 3.7, 7.4, 14.8, 18.5, 29.6, and 0 MBq of (32)P-CP, respectively, and the tumor volume on body surface was measured daily. The animals (n = 6) were sacrificed at 14 days after administration. The dynamic distribution of radioactivity in body (percentage of injected dose per g), morphological changes, the tumor-inhibiting rate (TIR), proliferating index (PI), proliferating cell nuclear antigen (PCNA) tumor microvascular density (MVD), continuous counting of white blood cells (WBCs) and platelets (PLTs) in venous blood, body weight, and toxic reactions were observed. RESULTS: The injected (32)P-CP mainly accumulated in the tumor mass and was retained for a long time. The TIR of each dosage group in order was 21.68%, 39.73%, 50.43%, 71.18%, and 74.09% (F = 159.74; p < 0.001), PI was 70.85, 67.90, 46.70, 20.66, 10.75, and 90.11 (F = 509.54; p < 0.001), and MVD count was 39.19, 28.33, 17.45, 8.89, 8.10, and 64.80 (F = 643.26; p < 0.001), respectively. The data for WBC, PLT, and body weight observed for 28 days in the treatment groups did not indicate significant differences compared with those of the control group. CONCLUSIONS: Interstitial injection of (32)P-CP seems to be a safe and effective interventional nuclide therapy for pancreatic carcinoma-bearing nude mice.