Optimal efficient imaging time for identification of sentinel lymph node with Tc-99m Tilmanocept in breast cancer patients

We determined the optimal imaging time for axillary lymph node (LN) visualization following Tc-99m Tilmanocept in breast cancer patients to establish imaging guidelines that can allow for a reliable and efficient yet high yield study prior to surgery. Retrospective analysis in 651 patients who underwent lymphoscintigraphy, comparing LN visualization on immediate, 15-minute, and 90-minute delayed imaging after injection of Tc-99m Tilmanocept. Statistical analysis was performed using McNemar's test, kappa coefficient, and Pearson Chi-square test. Five hundred and six patients had either immediate or immediate and 90-minute delayed imaging. Of these patients, 203 (40.1%) had both immediate and 90-minute delayed images. Of these 203 patients, 54 (26.6%) had ≥1 lymph node(s) identified immediately and 196 (96.6%) had ≥1 lymph node(s) identified at 90 minutes (P<0.0001). A kappa coefficient of .0256 was observed (95% CI: .0058-.0453). One hundred and forty-five additional patients had 15-minute delayed imaging. Of these patients, 117 (80.7%) had ≥1 lymph node(s) identified, which was significantly fewer compared to the number of patients with ≥1 lymph node(s) detected at 90 minutes (P<0.0001). Ninety-minute delayed imaging is optimal for identifying sentinel lymph node(s) following Tc-99m Tilmanocept injection in breast cancer patients.