FDG-PET/CT detection of very early breast cancer in women with breast microcalcification lesions found in mammography screening.

Introduction: To assess the efficacy of positron emission tomography/computed tomography with the glucose analogue 2-[(18) F]fluoro-2-deoxy-D-glucose (FDG-PET/CT) in Taiwanese women with early breast cancer detected by mammography screening.

Methods: Dual-time-point imaging of whole-body supine and breast prone scans using FDG-PET/CT were performed sequentially in the pre-operative stage.

Results: A total of 11,849 patients underwent screening mammography, of whom 1,209 (10.2%) displayed positive results. After further investigation, 54 patients underwent FDG-PET/CT. Post-operative pathology examinations revealed malignancies in 26 lesions, including invasive breast cancer in 11 cases and non-invasive breast cancer in 15 cases, as well as benign disease in 30 lesions. The FDG-PET/CT findings from the whole-body scans were positive for 9 of 11 invasive breast cancers (81.8%) and 3 of 15 non-invasive cancers (20%), and they were negative for all benign lesions. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of FDG-PET/CT with whole-body supine imaging were 46.2%, 100%, 100% and 68.2%, respectively. Breast prone imaging revealed another patient with ductal carcinoma in situ, increasing the sensitivity to 50%. Importantly, positive PET findings were significantly correlated with tumour histology (P = 0.006), tumour size (P = 0.039) and Ki-67 expression (P = 0.011).

Conclusions: FDG-PET/CT with whole-body scanning demonstrated high sensitivity to invasive breast cancer, limited sensitivity to non-invasive breast cancer, and high specificity for breast cancer. FDG-PET/CT might be useful for differentiating tumour invasiveness. However, the good PPV but poor NPV do not allow the physician to discard the biopsy.