Clinical trials for advanced gastrointestinal cancers in Japan. Japan Clinical Oncology Group Gastrointestinal Oncology Study Group.

No standard chemotherapy regimen for the treatment of advanced gastrointestinal cancer exists. However, 5-fluorouracil (5-FU) is being used more frequently as a key component of combination therapy regimens for this disease, and including cisplatin (CDDP) in combination therapy regimens produces significant tumor shrinkage. Although oral formulations of 5-FU are widely used in Japan, their clinical activity and toxicity have not been thoroughly evaluated. In 1992, the Japan Clinical Oncology Group initiated a phase III study in which the survival rates of patients treated with 5-FU 800 mg/m2/day for 5 days by continuous infusion (5-FUci), 5-FUci with CDDP 20 mg/ m2/day for 5 days by infusion, or oral uracil/Ftorafur 375 mg/m2/day with weekly MMC 5 mg/m2 i.v. were compared. This study was closed with 280 patients accrued in 1997, and final analysis was made in early 1998. Irinotecan and paclitaxel are new drugs with activity against gastric cancer. Combination chemotherapy consisting of irinotecan with CDDP has also been evaluated. For treatment of metastatic colorectal cancer, the only active drug previously available in Japan was 5-FU, although 5-FU + leucovorin is the international standard regimen. Irinotecan is now approved in Japan, Europe, and the USA and is the most effective drug for 5-FU-refractory patients. The optimal irinotecan and 5-FU combination regimen is being extensively examined but further trials aimed at accumulating basic data are warranted.