Detecting Colorectal Cancer Spread.

• Position: Brief Article

About one-third of people who have undergone surgery for colorectal cancer face development of additional tumors. Tests to detect cancer recurrence can give contradictory results, forcing doctors to perform exploratory surgeries that may be too late to be useful. A study at Washington University School of Medicine in St. Louis (Mo.) suggests that positron emission tomography (PET) can detect additional tumors early and reveal the extent to which the colorectal cancer has spread.

The researchers evaluated 22 patients who had warning signs of cancer based on elevated blood levels of a factor produced by tumor cells. Traditional means of imaging, such as computed tomography and magnetic resonance, did not reveal cancer. When PET imaging was used, it confirmed disease in 15 patients out of 17 who had tumors. The five patients whose PET scans were negative remained cancer-free for at least nine months of further observation.

Farrokh Dehdashti, lead investigator of the study and an assistant professor at the medical school's Mallinckrodt Institute of Radiology, says the results suggest that PET is a good option for patients with warning signs of cancer spread. "The whole focus is on detecting cancer recurrence early, and PET gives patients this chance."

PET...