Newer scan may spot recurrent breast cancer better

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http://www.reutershealth.com/archive/2002/03/08/eline/links/20020308elin003.

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Newer scan may spot recurrent breast cancer better

By Merritt McKinney

NEW YORK, Mar 08 (Reuters Health) - A type of imaging called positron

emission tomography (PET) may be more accurate than conventional techniques

for evaluating women who have been treated for breast cancer, California

researchers report.

" PET will be more accurate than conventional imaging to tell women whether

the disease has returned or is still in remission, " the study's lead author,

Dr. Johannes Czernin of the University of California, Los Angeles, told

Reuters Health.

The importance of this and other studies that demonstrate the benefits of

PET, Czernin said, is underscored by the recent announcement that Medicare

will cover the cost of the imaging for women who have been treated for

breast cancer.

Once a woman is treated for breast cancer, she regularly undergoes several

types of imaging tests to make sure that her cancer has not returned. These

tests include mammography, CT scans, magnetic resonance imaging (MRI) and

ultrasound.

The type of PET used in the study, known as FDG PET, works by measuring the

use of glucose, or sugar, in the body's cells. Since cancer cells consume

more sugar than normal cells, the scan identifies cancerous cells and shows

whether they have spread beyond the original location of the tumor.

Several studies have shown that FDG PET, a full-body scan, is more effective

than conventional tests for telling whether breast cancer has spread, or

metastasized. But whether PET is a useful tool for predicting a woman's

prognosis after treatment for breast cancer has been uncertain.

Czernin and his colleagues studied 61 women who had undergone both PET and a

combination of conventional imaging tests after being treated for breast

cancer. The women were followed for at least 6 months.

PET was more accurate than conventional imaging for both detecting and

ruling out cancer recurrence, the researchers report in the March issue of

the Journal of Nuclear Medicine.

The results of PET and conventional imaging were in agreement for 75% of the

women. In the remaining 25%, however, the techniques produced contradictory

results. Nine women had positive results on PET, meaning that cancer had

returned, but negative results on conventional imaging. PET was negative in

six women who had positive results on conventional imaging.

Based on the women's outcome 6 months after testing, PET turned out to be

correct in 12 of the 15 cases in which PET and conventional imaging produced

conflicting results. Conventional imaging was correct in only 3 of the 15

women.

" You get better information from a PET scan than from the combined

information derived from many other tests, " Czernin said.

In the report, the investigators note that the point at which cancer

recurrence is detected can affect treatment choices. If cancer is found

before it spreads beyond the breast, surgery or radiation may be effective.

Once cancer metastasizes, however, chemotherapy, radiation or both are

usually needed.

Right now, PET imaging is " vastly under-utilized, " according to Czernin. But

the number of women with breast cancer who are having PET is " increasing

dramatically, " he said.

The scan might also be useful for detecting breast cancer the first time

around, according to Czernin. One possible use of PET, he said, might be in

detecting cancer in women for whom mammograms are relatively less

effective--such as those with very dense breast tissue or those with scars

or implants.

SOURCE: Journal of Nuclear Medicine 2002;43:325-329.