Patients were eligible if they had undergone complete
resection of histologically proven stage II (T3
or T4,N0,M0) or stage III (any T,N1 or N2,M0) colon
cancer, as defined by the presence of the inferior
pole of the tumor above the peritoneal reflection
— that is, at least 15 cm from the anal margin.
Treatment had to be started within seven weeks after
surgery. Other eligibility criteria included an age
of 18 to 75 years; a Karnofsky performance-status
score of at least 60; a carcinoembryonic antigen
level of less than 10 ng per milliliter; the absence of
prior chemotherapy, immunotherapy, or radiotherapy;
and adequate blood counts and liver and
kidney function. Written informed consent was required
from all patients, and the study was approved
by the ethics committees of the participating
centers.