Detection capability of the Medical Imaging Projection System for sentinel lymph node biopsy in patients with breast cancer with and without neoadjuvant chemotherapy: a retrospective study.

Background: The Medical Imaging Projection System (MIPS) projects fluorescence ICG images on the surgical field. In this study, we aimed to assess sentinel lymph node (SLN) identification by the MIPS in patients with and without neoadjuvant chemotherapy (NAC) administration and compare the utility of the MIPS with the radioisotope (RI) method.

Methods: We retrospectively reviewed medical records of patients with primary breast cancer who underwent SLN biopsy using the MIPS at Kyoto University Hospital between April 2020 and December 2024. The primary endpoint was the identification rate of SLNs. The secondary endpoints included the number of positive SLNs and SLNs detected per patient.

Results: The analysis included 470 procedures (448 patients), of which 56 (11.9%) were conducted after NAC. The identification rate of SLNs by the MIPS was 99.6% (95% confidence interval [CI], 98.5-99.9) in all procedures and 98.2% (95% CI, 90.6-99.7) after NAC. The median number of SLNs identified per patient was 3 (range, 2-4) by the MIPS and 2 (range, 1-3) by the RI method (P < 0.001). No significant difference was observed in the number of SLNs between patients who received NAC and those who did not (3 vs 3, P = 0.84). Seventy-eight positive SLNs were excised, all of which were accurately identified by the MIPS.

Conclusions: This study suggested that the identification rate of SLNs by the MIPS was high regardless of the presence or absence of preceding systemic chemotherapy.