Combo PET/CT Scan Helps Spot Breast Cancer's Spread

Combo PET/CT Scan Helps Spot Breast Cancer's Spread
TUESDAY, Nov. 27 (HealthDay News) -- A technique that combines aPET scan with a CT scan can help spot the spread of inflammatory breastcancer, a rare but very aggressive form of the disease, researchersreport.
"It is a quicker way of assessing everything," said lead researcher Dr.Selin Carkaci, assistant professor of radiology at The University of TexasM.D. Anderson Cancer Center in Houston. "Our results show it is veryuseful," she said.
Carkaci was expected to present her findings Monday at the annualmeeting of the Radiological Society of North America, in Chicago.
According to the American Cancer Society, IBC accounts for 1 percent to5 percent of all breast cancer cases in the United States. Often by thetime it is discovered, it has spread. The five-year survival rate forthose with IBC is 25 percent to 50 percent, according to the cancersociety.
The new combo technology has been used in recent years for assessingother cancers as well, Carkaci noted. While the separate technologies ofPET (positron emission tomography) and CT (computed tomography) have beenin use since the early 1970s, their combined use came into practice onlyabout eight years ago. Patients being treated at cancer centers across theUnited States should have access to this test, which is becoming morecommon, Carkaci said.
The technique she used is called FDG-PET/CT -- for "F-18fluorodeoxyglucose positron emission tomography and computed tomography".
In a PET scan, a small amount of the radioactive drug F-18-labeledglucose is injected into the body. Fast-growing cancer cells feed onsugars and absorb it more quickly than do normal cells, Carkaci explained,so they "light up" on the images created by the PET scanner.
On the other hand, "the CT scanner takes a series of X-ray pictures,which are combined by a computer to create an extremely detailed image ofthe internal organs or other parts of the body," she said.
The scan gives great anatomical detail including the size, shape andlocation of the tumor. Together, the tests provide the most complete dataon the tumor and its spread, Carkaci said.
In the study, doctors scanned 41 women newly diagnosed withinflammatory breast cancer. They found metastases in 20 patients, or 49percent. They used biopsy or additional imaging to confirm the resultswhen possible. Biopsy confirmation of metastases were available in four of13 patients and additional imaging confirmation in nine.
"We found that FDG-PET/CT is 95 percent accurate in identifying distantmetastases and 98 percent accurate in identifying regional lymph nodemetastases," Carkaci said.
"This [scanning] is done immediately after diagnosis, and thenfollowing the chemotherapy, to evaluate the response to treatment," shesaid.
The hope is to stop the cancer in its tracks.
One co-author, Dr. Homer Macapinlac, chair and professor of nuclearmedicine at M.D. Anderson, reported being a consultant for GeneralElectric Company and Siemens AG. Both companies produce scanners.
The study findings are "significant for the high rate of metastaticdisease, with almost one half of the women with PET/CT able to identifythe tumors at an early stage," said Dr. David Bluemke, professor ofradiology and medicine and clinical director, MRI, Johns Hopkins MedicalInstitution, Baltimore.
"The data is very compelling for routine and early use of PET/CT forpatients with inflammatory breast cancer," he said. "Although the studywas small, the high accuracy rate appears promising for patients with thiscondition."
More information
To learn more about inflammatory breast cancer, visit the U.S. National Cancer Institute.