Surgery continues to play an important role in the curative treatment of gastrointestinal cancer. Recently, considerable progress has been made in chemotherapy and radiotherapy. In particular, chemotherapy with FOLFIRI and FOLFOX has prolonged survival in patients with colorectal cancer. Molecular-targeted agents have also enhanced the effectiveness of chemotherapy. However, radical resection offers the potential for a cure and is unsurpassed by any other treatments. Nonetheless, further improvement in survival is unlikely to be achieved by surgery alone. Studying how treatment regimens highly effective against unresectable or recurrent colorectal cancer can be adapted to patients with resectable disease is thus an important issue.