MINNEAPOLIS--Breast imaging with FDG PET can identify breast cancer with a high specificity, a German study has shown. This technique visualizes malignant tumor tissue by increased FDG (fluorine-18-fluorodeoxyglucose) uptake (see image on " FDG PET Imaging Visualizes Malignant Breast Lesions"), said Norbert Avril, MD, of the Department of Nuclear Medicine, Technical University, Munich.
The study, presented at the Society of Nuclear Medicine meeting, included 71 patients scheduled for breast biopsy. Two observers classified lesions seen on PET imaging as definitely malignant (37 of 95 lesions), probably malignant (16 lesions), or unlikely to be malignant (42 lesions). Biopsy results showed that 49 of the 95 tumors were malignant and 46 were benign, Dr. Avril said.
When the 16 lesions that were classified as "probably malignant" on PET imaging were considered as negative, sensitivity was 74% and specificity, 98%. If "probably malignant" results were regarded as positive, sensitivity was 88% and specificity, 78%.
There was a significant difference between FDG uptake of benign lesions (SUV, or standardized uptake value, of 1.4 ± 0.4) and malignant tumors (SUV of 3.6 ± 2.5), Dr. Avril said. A SUV of 2.3 represented the highest value for benign breast lesions, and all tumors with higher SUV values were found to be malignant. However, there was an overlap between benign and malignant tumors for SUV values lower than 2.3.
Although most of the research with FDG PET in breast lesions is being conducted to gain a better understanding of breast tumor physiology, the technique does have potential clinical benefits, Dr. Avril said.
"This imaging procedure can provide more accurate preoperative staging of disease," he said. "PET can show metastatic spread to the lymph nodes in the axilla, which cannot be detected by mammog-raphy." This means that the results could influence the type of surgery performed and enable physicians to decide which patients are appropriate for breast conservation therapy, he added.