Surgery of nonpalpable breast cancer: First step to a virtual per-operative localization? First step to virtual breast cancer localization.

Introduction: Preoperative localization procedures of occult breast cancer (radioisotopic and wire localization) are invasive and uncomfortable. We have evaluated a novel technique which allows a virtual localization.

Material And Methods: Our retrospective study focused on patients treated for occult and unifocal breast cancer from September 2016 to June 2017. All patients had radioisotopic preoperative localization. We included patients who had a preoperative prone Magnetic Resonance Imaging (MRI) and an intraoperative 3D optical scan. During surgery, the surgeon localized the tumor thanks to a gamma detection probe and marked the localization on the skin with a black marker. The breast was then optically scanned. MRI was adjusted to the optical surface to match the exact breast position in the Operating Room. The virtual localization provided by the 3D breast modeling tool was retrospectively compared with the radioisotopic localization, defined as the pen mark visible in the optical scan.

Results: Nine patients were included in this feasibility study. Tumors were successfully localized in the respective breast quadrant. The mean cutaneous distance between virtual and radioisotopic localization was 1.4 cm in patients with low breast volume (5/9) and 2.8 cm in those with large breast volume (4/9).

Conclusion: We developed a research prototype which enables virtual preoperative localization of nonpalpable breast lesions using MRI images and intraoperative optical scanning. Parameter optimization is required and will lead to a precise and noninvasive tool. By adding augmented reality, it will be possible to initiate a prospective study to compare this tool with the traditional localizations.