[A case of unresectable multiple hepatic metastases from colorectal cancer successfully treated with IRIS (S-1, CPT-11) therapy].

In a patient with multiple liver metastases of colorectal cancer whose tumor response had been achieved by 5-FU hepatic arterial infusion, a catheter for arterial infusion chemotherapy was occluded resulting in re-elevation of tumor marker levels. For this reason, a second-line IRIS therapy using S-1 and CPT-11 was started. IRIS therapy reduced tumor marker levels to a degree greater than that of previously achieved with 5-FU hepatic arterial infusion, and a diagnostic imaging allowed a judgment of partial response. Although a ratio of liver tumor volume to liver volume was 57% on admission of this patient, the ratio was reduced to 16% by the 14th course of 5-FU hepatic arterial infusion immediately before the catheter was occluded. The ratio was 18% after the 7th course of IRIS therapy, and the diagnostic imaging showed a partial response. Hepatic arterial infusion therapy is one of the treatment methods characterized by a lower incidence of adverse reactions, relatively low cost, and expectation of high anti-tumor efficacy as compared to chemotherapy such as FOLFIRI. IRIS therapy does not require a port insertion and it costs about a half of FOLFIRI therapy. When used as a second-line therapy for unresectable colorectal cancer, IRIS therapy has demonstrated non-inferiority compared to FOLFIRI in a phase III clinica (l FIRIS) study.