^99mTc-tilmanocept versus ^99mTc-sulfur colloid in lymphoscintigraphy: Sentinel lymph node identification and patient-reported pain

Lymphoscintigraphy plays a vital role in sentinel lymph node (SLN) identification in oncologic breast surgery. The effectiveness of SLN localization and the degree of patient pain were compared between filtered ^99mTc-sulfur colloid (^99mTc-SC) and ^99mTc-tilmanocept. Methods: A retrospective review of patients undergoing lymphoscintigraphy for breast cancer using ^99mTc-SC (June 1, 2010, to December 31, 2011) or ^99mTc-tilmanocept (June 1, 2013, to January 31, 2014) was performed. SLN appearance time and uptake, SLN pathology, proportion of positive SLNs removed, and pain scores were compared for each radiopharmaceutical using the χ² test, Fisher exact test, and unequal variance t test, as appropriate. Results: In total, 76 patients, with 86 evaluated axillae, underwent lymphoscintigraphy: 29 with ^99mTc-SC and 47 with ^99mTc-tilmanocept. The mean SLN appearance time was 11.0 min for ^99mTc-SC and 19.3 min for ^99mTc-tilmanocept (P 5 0.003). There was no difference in the mean transit uptake percentage: 2.2% for ^99mTc-SC and 1.9% for ^99mTc-tilmanocept (P 5 0.55). ^99mTc-tilmanocept identified a greater proportion of intraoperative blue nodes than did ^99mTc-SC (P 5 0.03). There was no significant difference between ^99mTc-SC and ^99mTc-tilmanocept in the number of SLNs removed, number of patients with positive SLNs, or pain score. Conclusion: ^99mTc-SC use in lymphoscintigraphy is an acceptable alternative to ^99mTc-tilmanocept for SLN detection in breast cancer, on the basis of the similarity in intraoperative SLN identification and pain scores.