Finding a Tumor's True Colors

Researchers have devised a new imaging technique for catching subtle differences between benign and malignant breast tumors. The approach, described in this month's Nature Medicine, could provide doctors with the first noninvasive method for diagnosing breast tumor types.

Doctors rely on mammograms and biopsies to hunt down breast tumors. Because mammograms are unable to distinguish between most benign and malignant tumors, surgical biopsies are used to retrieve a tissue sample to reveal the tumor type. Biopsies, however, can hurt.

Hoping to find a less painful way to probe a tumor's character, Hadassa Degani, a clinician at the Weizmann Institute of Science in Rehovot, Israel, combined magnetic resonance imaging with a nontoxic compound called GdDTPA, which serves as an MRI contrast agent because it resonates at a distinct frequency. Degani's group first tried the technique on mice with transplanted human breast tumors. After imaging a tumor, Degani injected a mouse with GdDTPA, then conducted scans 3.5 and 12 minutes later. Using a computer to color code the rate at which GdDTPA entered the tumors, Degani found that the chemical infiltrated malignant tumors far more quickly than it did benign tumors. Her team noted a similar trend in 18 people with malignant or benign breast tumors.

The technique appears to be "exquisitely sensitive," says Faina Shtern, associate director for research and technology at the U.S. Public Health Service's Office of Women's Health. If the work passes muster after being tested in more patients, Shtern says, it could reduce the whopping number of breast biopsies on women whose tumors turn out to be benign or those who had false dark patches on their mammograms.