THURSDAY, March 7, 2002 (HealthDayNews) -- One of the most devastating aspects of having breast cancer is never knowing if or when it will return.
Now, a new study says there is a way to reduce that trepidation and know with some degree of certainty that you really are disease-free.
A report published today in the Journal of Nuclear Medicine found a particular type of nuclear imaging known as an FDG PET scan (positron emission tomography) can detect disease recurrence much more accurately than conventional forms of imaging, including X-rays, magnetic resonance imaging (MRIs), CT scans and sonography.
"When you have treatment for breast cancer, the treatment itself can cause a number of problems, such as inflammation or even scar tissue that, upon conventional imaging, can appear as a mass," says study author Dr. Johannes Czernin, of the department of nuclear medicine at the UCLA School of Medicine.
What conventional imaging can't tell you, Czernin says, is whether that mass is malignant.
However, the PET system of imaging can make that important distinction, and it can detect some masses that conventional imaging can't, experts say.
"Rather than just taking just a picture of a tumor or mass, the PET scan is actually able to measure the 'living chemistry' of that mass, and tell us with some degree of certainty if a malignancy is at work or not," says Dr. Steven M. Larson, chief of the Nuclear Medicine Service at Memorial Sloan-Kettering Cancer Center in New York City.
To view that " living chemistry," patients are given an injection of a harmless radioactive substance that acts as a kind of homing device, traveling through the body and collecting in areas where a mass exists.
If that tumor is malignant, PET scanning causes the image on a computer screen to light up, indicating a metabolic "hot spot" -- a mass that is burning energy at a faster rate than normal tissue. This, doctors say, is often a sure sign a tumor is malignant.
For the women in the study, the PET scan effectively showed which women were harboring "hot spots" -- indicating recurrence of disease -- and which ones were cancer-free.
"This is a well-done study that concurs with our own findings about the PET scan. It is highly consistent with the work we have done in this area, and I believe represents an important finding about the usefulness of PET scans in breast cancer patients," Larson says.
However, he cautions that "we also need more studies to back up these findings, so we can know with much more certainty which subgroups of patients will benefit most from this technology."
The new research involved 61 women, all of whom underwent breast cancer surgery. In addition, 46 of the women got chemotherapy, and 34 received radiation therapy. Each woman also had some form of conventional imaging -- MRI, X-ray or CT scan -- to check for disease recurrence.
Soon after that, they all received whole body PET scans. Forty-two women were evaluated for residual or recurrent disease, 10 were tested because of increased blood levels of tumor markers, and nine had suspicious findings from the conventional imaging.
After the PET scans, the women were followed for a minimum of six months, to check for disease recurrence.
The result: Six of the 61 women in the study who had positive conventional imaging tests but negative PET scans were found to be cancer-free. Six of nine women who had a negative finding with conventional imaging but a positive PET scan were found to have recurrent disease.
Overall, the study found a difference between PET scan findings and conventional imaging existed for about 25 percent of the women, with PET correctly predicting disease outcome 80 percent of the time. Conventional imaging was right in only 20 percent of the cases.
The PET scans were also better at determining the length of disease-free survival, accurate 90 percent of the time, compared to 75 percent for conventional imaging.
PET was also almost 15 percent more sensitive in finding tumors, and approximately 16 percent more specific in identifying what was found.
There was, however, one caveat: all six women who were identified as positive for disease by the PET scan, and who received follow-up chemotherapy, radiation or surgery, remained positive for disease, a strong indication that the screening did not impact remission.
However, the authors believe it may have significantly delayed disease progression.
"What is of equal significance is that, for the women who were given a clean bill of health with a negative PET scan, this was information they could be very sure of. It gave them an important sense of security knowing that they were really healthy and did not have to worry," Czernin says.
Less than one week ago, breast cancer patients received even more good news: The federal government announced that Medicare would reimburse PET scans following breast cancer treatment.
What To Do
For more information on how PET scans work, visit The American College of Radiology.
To learn more about breast cancer treatments and technologies, check out The National Alliance of Breast Cancer Organizations.
