Intraperitoneal radioimmunotherapy in treating peritoneal carcinomatosis of colon cancer in mice compared with systemic radioimmunotherapy

医薬保健研究域医学系
Peritoneal spread is one of major causes of mortality in colorectal cancer patients. In the current investigation, the efficacy of radio-immunotherapy (RIT) with i.p. administration of an anti-colorectal cancer IgG1, 131 I-A7, was compared to that with i.v. administration in BALB/c female mice bearing peritoneal nodules of LS180 human colon cancer cells, at the same toxicity level. Distribution of either i.p. or i.v. administered 131 I-A7 and i.p. administered irrelevant 131 I-HPMS-1 was assessed. Based on the results of toxicity determination at increments of 2 MBq and estimated dosimetry, an i.p. dose of 11 MBq and an i.v. dose of 9 MBq were chosen for treatment. Mice were monitored for long-term survival: untreated mice (n=11), mice undergoing i.p. RIT with 131 I-A7 (n=11), mice undergoing i.v. RIT with 131 I-A7 (n=11) and mice undergoing non-specific i.p. RIT with 131 I-HPMS-1 (n=5). Intraperitoneal injection of 131 I-A7 produced faster and greater tumor accumulation than i.v. injection: 34.2±16.5% of the injected dose per g (% ID/ g) and 11.1±3.6% ID/g at 2 h, respectively (P