Tumor Markers, MoAbs May Help Individualize Colon Cancer Therapy

PHILADELPHIA—Biologic tumor markers, in combination with the Duke’s anatomic staging system, may point the way toward the individualization of colo-rectal cancer treatment, says Daniel G. Haller, MD, of the University of Pennsylvania Medical Center.

Treatment would be at an appropriate level of intensity based on the patient’s specific risk and individual situation, Dr. Haller said. “I think it’s time every 50 years to reinvent how you treat patients,” he added.

Potentially predictive tumor-associated variables include mutations in chromosome 18, gene deletions, and thy-midylate synthase (TS) levels.

High TS Predicts Worse Outcome

In a presentation at Fox Chase Cancer Center’s annual Toward 2000 Symposium, Dr. Haller noted that high TS levels predicted a worse outcome in retrospective studies of rectal cancer conducted by the NSABP, but those same patients were the ones apparently most sensitive to chemotherapy.

“I think we need to look at treatment sensitivity as well as tumor biology, two very different aspects of the disease,” he commented.

One particularly novel agent under study for colorectal cancer is a humanized murine monoclonal antibody, known as 17-1A, that recognizes a cell surface glycoprotein and can induce antibody-dependent cellular cytotoxicity in laboratory systems.

Dr. Haller said that the antibody has been tested in Germany in patients with stage III colorectal cancer, and that two more trials are now under way comparing 17-1A with standard colorectal cancer treatments.