After the Tumor

By Christine Gorman

Doctors have learned a lot over the past decade about how to treat colon cancer. But given that it strikes 130,000 Americans each year, there's surprisingly little research about the best way to monitor a patient's condition after his or her tumor has been removed. The goal, of course, is to catch any metastasis, or spreading of the original cancer, while it is still small and treatable. To do that, physicians rely on everything from blood tests to computerized X rays, or C.T. scans, to detect new tumors in the liver and lungs, among other places. Unfortunately, no one knows which combination of tests over what time frame offers the best results.

That uncertainty may be getting cleared up. Last week a panel of experts from the American Society of Clinical Oncology published the first scientifically based guidelines for monitoring the return of colon cancer. The report, which is based on a review of 20 years of data, is bound to stir up controversy, however, because it suggests a minimalist approach for patients with no new symptoms. Doctors must always ask themselves whether a given test will do their patients any good, says Dr. Al Benson, the panel's co-chair and a medical oncologist at Northwestern University in Chicago. After all, he notes, "some of these tests are not entirely benign."

First, a note of caution. The new guidelines are a work in progress and should not supersede your doctor's best judgment. Nor do they apply if you are participating in a clinical trial or have been diagnosed with hereditary colon cancer.

And now some background. Colon cancer is highly curable when caught in the earliest stages. However, most relapses, when they occur, show up within five years of the initial treatment and are usually fatal. Perhaps 5% of metastasizing tumors are small enough to give patients a reasonable chance for complete cure. So there's a premium on finding and treating them early.

According to the new guidelines, the most effective follow-up procedures are colonoscopy (in which a physician uses a flexible tube to look at the inside of your bowel) and regular visits with a physician (who can coordinate your postsurgical treatment, answer questions and investigate new symptoms). Benson and his colleagues concluded that patients should undergo a colonoscopy three years after the one that was done at the time of surgery, provided that all cancers and polyps were removed. Why not sooner? Repeat colonoscopies are most useful for finding a new tumor unrelated to the old one. Most recurring colon cancers form elsewhere in the body, and most new cancers take time to grow.

Two other tests received qualified endorsements. The CEA test, which detects as many as 80% of colon-cancer recurrences, measures the amount of carcinoembryonic antigen, a protein found in the blood that is often produced by tumor cells. Regular proctosigmoidoscopy, which looks directly at the rectum, is recommended for patients with rectal cancer who have not undergone standard treatment with radiation.

C.T. scans and chest X rays did not catch enough metastases early enough to justify their routine use--at least for now. But that could change as doctors develop new techniques for monitoring their patients.

Read the new colon cancer monitoring guidelines on the Web at www.asco.org E-mail Christine at gorman@time.com