Colorectal cancer. Principles of postoperative follow-up.

Monitoring patients after primary large bowel surgery for malignancy is predicated on the concept that early detection of recurrence may provide salvage treatment for cure. Knowledge of the pathologic site and stage provides important information as to the probability of recurrence and the patterns of failure that are likely to occur. Available methods to detect recurrence include clinical, roentgenographic, and serum tests that are done more frequently during the first 2 years after surgery. Monitoring plasma carcinoembryonic antigen levels can lead to identification of asymptomatic recurrences, but there is controversy about the curability of recurrences outside the liver. Newer techniques (such as computed tomographic portography, intraoperative ultrasonography, and radioimmunoguided surgery) provide greater diagnostic accuracy and lead to more appropriate procedures during "second-look" operations. For example, hepatic resection in properly selected patients offers up to a 30% chance of cure and should be pursued aggressively. A search for metachronous cancers by endoscopy also should be done. Knowledge of the potential and patterns of failure can provide a useful guide during the postoperative follow-up care of the patient with large bowel cancer.