The DNA ploidy and DNA indices (DI) of 414 colorectal cancer patients treated in Tottori University Hospital between 1976 and 1994 were analyzed. The incidence of patients with hepatic recurrence was found to be significantly higher in those with aneuploid tumors and a DI above 1.5 than in those with diploid tumors and a DI below 1.4 or in those with diploid tumors and a DI equal to 1.0. A total of 110 colorectal cancer patients was randomly divided into two groups as a prophylactic portal infusion chemotherapy (PPIC) group and control I (a peripheral venous chemotherapy group) to confirm the effectiveness of PPIC as adjuvant therapy for prevention of hepatic recurrence. 5-FU (3mg/kg/day) was administered for two postoperative weeks and mitomycin C (10mg/body) was administered at day 0, day 7, day 14, via respective route. The incidence of hepatic recurrence in the patients with cancer of DI above 1.5 was significantly lower in the PPIC group compared to control group I (8% vs. 38%). Next, we examined that, which is superior as adjuvant chemotherapy via hepatic artery or via peripheral vein, using the same anticancer drugs and dosages mentioned above. There was no difference in recurrence rate between hepatic arterial infusion chemotherapy (HAIC) and peripheral vein group (control II) (22% vs. 23%), even in the patients with DI above 1.5 (13% vs. 17%). These findings suggest that colorectal cancer with DI above 1.5 may have a strong tendency to metastasize to the liver, and that PPIC may be more effective for prevention of hepatic recurrence compared to HAIC. We are processing the next regimen of PPIC using continuous infusion of 5FU (150mg/m2/day) and cisplatin (3mg/m2/day) for 3 weeks to confirm the effectiveness of new PPIC in the patients with cancer of DI above 1.5 as a high risk group of hepatic recurrence. Preliminary data showed the better disease free 5-year survival in new PIPC compared to control III(without infusion chemotherapy) (88% vs. 64%), and the reduced hepatic recurrence (no cases in PPIC and 4 cases in control). The new PIPC for the patients with DI above 1.5 was effective for prevention of hepatic recurrence.
