Abstract: Objective：To explore the feasibility and safety of breastconserving surgery after tumor mass removal by ultrasoundguided vacuumassisted biopsy (VAB). Methods：Fortyfive cases of invasive ductal carcinoma (IDC) who underwent breastconserving surgery after removal of tumor mass by VAB from January 2008 to December 2014 were selected as the VAB group. A total of 147 cases of IDC who underwent breastconserving surgery after removal of tumor mass (single and less than 2 cm) by open excision during the same period were selected as the control group. The clinicalpathological characteristics and survival prognosis of the two groups were analyzed and compared. Results：All cases in VAB group had a single, impalpable tumor mass less than 2 cm, which was presumed benign according to imaging examination. There was only one puncture in all VAB operations, and the average distance from the puncture point to the tumor mass was (2.52±0.89) cm. The median incision was 8 times, the imaging examination showed complete resection, the mean operation time was (25.4±7.6) min, and no active bleeding occurred during operation. Breast conserving surgery was performed (4.50±0.92) d after VAB. Residual cavity, needle tract and skin puncture site were excised completely with negative margin. No tumor cell displacement in needle tract or skin site was observed. Ductal carcinoma in situ (DCIS) rather than invasive carcinoma was observed in residual cavity in three cases. There were no statistically significant differences between two groups either in mean age, age structure, tumor size, histological grade, vessel invasion, lymph node staging, sentinel lymph node positive rate, molecular type, adjuvant therapy or axillary surgery, or in 5year DFS or 5year OS as well. Conclusions：Breastconserving surgery after impalpable small breast cancer mass removal by ultrasoundguided VAB is safe and feasible.