Comparison of 99mTc-Phytate and 99mTc-Antimony Trisulfide in sentinel lymph node detection: a lymphoscintigraphy study in breast cancer patients

Abstract

Sentinel lymph node biopsy is critical for breast cancer staging and management. While 99mTc-Phytate is the established standard radiotracer, 99mTc-Antimony Trisulfide has limited clinical application due to radiopharmaceutical supply constraints. This proof-of-concept study evaluates both radiotracers’ diagnostic effectiveness and validates 99mTc-Antimony Trisulfide as a viable alternative. This institutional study included 39 breast cancer patients undergoing sentinel lymph node biopsy. Patients received either 99mTc-Phytate (n = 28; 71.8%) or 99mTc-Antimony Trisulfide (n = 10; 25.6%) via periareolar (n = 24) or peritumoral (n = 15) injection. Sentinel lymph node identification and gamma probe concordance were analyzed. Mean patient age was 53.5 ± 9.5 years. Invasive ductal carcinoma predominated (87%). 99mTc-Phytate achieved 100% detection (28 of 28 patients), while 99mTc-Antimony Trisulfide achieved 90.9% (10 of 11 patients). Intraoperative gamma probe concordance was 100% in all successfully visualized cases (38 of 38). Both radiotracers effectively identify sentinel lymph nodes with high diagnostic accuracy. While 99mTc-Phytate remains the preferred first-line agent, 99mTc-Antimony Trisulfide represents a validated alternative, particularly valuable in resource-limited settings or during radiopharmaceutical supply disruptions.