Internal iliac arterial infusion chemotherapy for rabbit invasive bladder cancer

Internal iliac arterial infusion (IA) chemotherapy has been used clinically for locally invasive bladder cancer, but there have been no experimental studies to actually demonstrate whether IA is more effective than intravenous infusion (i.v.) chemotherapy in this setting.

We compared the effects of IA and i.v. using a rabbit invasive bladder cancer model. A 0.2 mL suspension containing 2 x 10(6) VX2 cancer cells was inoculated into the posterior submucosa of the bladder. Two weeks later the rabbits were divided into 3 treatment groups of 8 rabbits each: controls, a group treated with IA consisting of 10 mg/kg carboplatin and 1 mg/kg pirarubicin once a week for 3 weeks (days 14, 21, and 28), and the third treated with the same regimen intravenously.

All bladder tumors of the rabbits in the IA group decreased in size, and 3 of the tumors totally disappeared (37.5%). There was also no evidence of lung metastasis. All tumors in the rabbits in the i.v. treatment group increased in size (tumor volume of IA vs. i.v., P = 0.008) and 2 rabbits had lung metastases. All tumors of the control group increased in size and all rabbits had lung metastases. The concentrations of platinum and pirarubicin in the bladder tumors were significantly higher in the IA treatment group than those in the i.v. treatment group at time points from 5 to 10 minutes (P < 0.05) after drug infusion.

The antitumor effect of IA may be due to higher drug concentrations in the early stage after drug delivery, and the initial circulation of high concentrations of drugs may be the most important factor in suppressing tumor growth.