Three-dimensional ultrasound imaging of breast cancer by a realtime intraoperative navigation system

Background: In order to achieve a good cosmetic result without increasing the risk of ipsilateral breast cancer recurrence after breast conserving surgery, it is very important to minimize the resection volume of the breast without compromising the negativity of the surgical margin. For this purpose, it is necessary to obtain precise information on tumor extension. We therefore developed a three-dimensional (3-D) ultrasound navigation system for breast cancer surgery, which can be performed in the operating room just before surgery. Methods: We obtained 3-D breast tumor images by the 3-D ultrasound navigation system in 40 patients with primary breast cancer (stage 0-II) who underwent mastectomy or breast conserving surgery. The tumor size was measured in a coronal view of the 3-D tumor image and compared with the tumor size obtained from a pathological map of the tumor extension. Results: We obtained 3-D tumor images in 38 patients (success rate = 95%). The tumor size in the images showed a very strong correlation with the pathological tumor size (r = 0.898). The difference in tumor size between the 3-D images and pathology was less than 1 cm in 29 tumors (76.3%) and less than 2 cm in 36 (94.7%). On the other hand, the difference in tumor size between palpation and pathology was less than 1 cm in 19 out of 38 tumors (50.0%) and less than 2 cm in 29 tumors (76.3%). The absolute difference between the 3-D images and pathology was significantly less than that between palpation and pathology (p = 0.0197). Conclusions: Our 3-D ultrasound navigation system is useful in visualizing breast tumor extension and is more accurate than palpation. The system is expected to be helpful in deciding on the appropriate surgical margin in breast cancer surgery, resulting in a better cosmetic outcome without increasing the risk of surgical margin positivity.