18F-fluorodeoxyglucose uptake as predictor for invasion in preoperatively diagnosed breast ductal carcinoma in situ: Significance in cases without mass formation

A diagnosis of ductal carcinoma in situ (DCIS) at needle biopsy often changes to that of invasive ductal carcinoma as the definitive pathological diagnosis following the surgical procedure. The present study sought to identify the factors associated with invasive disease in cases diagnosed as DCIS on needle biopsy by analyzing 18F-fluorodeoxyglucose-proton emission tomography (FDG-PET) findings. The present study retrospectively investigated the cases of 24 consecutive patients with primary breast cancer who were preoperatively diagnosed with DCIS by needle biopsy. The cases were divided into two groups based on the presence of invasion in the primary tumor. Among the 24 patients, 13 (54.7%) patients had invasive carcinoma and 11 (45.8%) had DCIS. The analysis revealed that the presence of FDG uptake in the tumor was the only independent predictor of presence of the invasive disease. No cases without FDG uptake exhibited invasion and all of these were ultimately diagnosed as DCIS. In the present study, all cases, including DCIS, with a nodular growth pattern demonstrated FDG uptake in the tumors, and all cases without FDG uptake were interpreted as having a diffuse growth pattern. The present findings suggested that the presence of FDG uptake in the tumor can be considered a predictor for invasion in cases with DCIS by needle biopsy, particularly in cases with a diffuse growth pattern. Patients preoperatively diagnosed as DCIS without mass formation and without FDG uptake in the tumor may avoid sentinel lymph node biopsy.