
Two decades since the first demonstration that fluorouracil (5-FU)-based adjuvant chemotherapy improves outcomes in resected colon cancer,[1] clinicians are still struggling with the question of which patients with stage II colon cancer should receive postoperative therapy. It is well-accepted that the absolute survival benefit associated with 5-FU–based therapy for unselected patients with stage II colon cancer is in the range of 3% at 5 years. But it is also obvious that some patients with stage II cancers have excellent outcomes and do not require additional therapy, whereas other patients have cancers that biologically behave more like stage III tumors.



