Clinical Significance of Focal Breast Lesions Incidentally Identified by 18F-FDG PET/CT

Cho, Young Seok; Choi, Joon Young; Lee, Su Jin; Hyun, Seung Hyup; Lee, Ji Young; Choi, Yong; Choe, Yearn Seong; Lee, Kyung Han; Kim, Byung Tae

Abstract

PURPOSE: We evaluated the incidence and malignant risk of focal breast lesions incidentally detected by 18F-FDG PET/CT. Various PET/CT findings of the breast lesions were also analyzed to improve the differentiation between benign from malignant focal breast lesions.
MATERIALS AND METHODS
The subjects were 3,768 consecutive 18F-FDG PET/CT exams performed in adult females without a history of breast cancer. A focal breast lesion was defined as a focal 18F-FDG uptake or a focal nodular lesion on CT image irrespective of 18F-FDG uptake in the breasts. The maximum SUV and CT pattern of focal breast lesions were evaluated, and were compared with final diagnosis.
RESULTS
The incidence of focal breast lesions on PET/CT in adult female subjects was 1.4% (58 lesions in 53 subjects). In finally confirmed 53 lesions of 48 subjects, 11 lesions of 8 subjects (20.8%) were proven to be malignant. When the PET/CT patterns suggesting benignancy (maximum attenuation value > 75 HU or < 30 HU; standard deviation of mean attenuation > 20) were added as diagnostic criteria of PET/CT to differentiate benign from malignant breast lesions along with maximum SUV, the area under ROC curve of PET/CT was significantly increased compared with maximum SUV alone (0.680+/-0.093 vs. 0.786+/-0.076, p<0.05).
CONCLUSION
The malignant risk of focal breast lesions incidentally found on 18F-FDG PET/CT is not low, deserving further diagnostic confirmation. Image interpretation considering both 18F-FDG uptake and PET/CT pattern may be helpful to improve the differentiation from malignant and benign focal breast lesion.