Differences between the clinical and histopathological tumor stages in breast cancer diagnosed using vacuum-assisted breast biopsy

The present study aimed to determine the difference between the clinical tumor stage (T stage) based on pre-operative ultrasound and the histopathological T stage subsequent to surgery in vacuum-assisted breast biopsy (VABB)-diagnosed breast cancer. Tumor sizes measured ultrasonography (USG) and histologically were retrospectively calculated and analyzed using paired t-tests in 209 patients diagnosed with breast cancer using VABB. The patients were classified into two groups, consisting of breast imaging reporting and data system (BI-RADS) category 4a or below, who underwent complete resection by VABB, and BI-RADS category 4b or above, who underwent incisional biopsy by VABB. The histopathological tumor size was found to be smaller compared with the USG-determined size in 92.3% of pT1a, 75.5% of pT1b, 44.2% of pT1c, 47.7% of pT2 and 0% of pT3 cases. Furthermore, the histopathological tumor size was smaller compared with the USG-determined size in 62.8% of cases classified as BI-RADS category 3–4a and in 53.7% of cases classified as BI-RADS category 4b-5. The smaller the primary tumor at the time of diagnosis by VABB, the higher the likelihood of pathological underestimation on post-operative histopathological assessment compared to pre-operative USG.