Vincent Reid, MD1; Sarah Pauley, MD, PhD2
1Hall-Perrine Cancer Center, Mercy Medical Center, Cedar Rapids, IA; email@example.com
2Radiology Consultants of Iowa, Cedar Rapids, IA
Our institution performed a series of case studies over 30 days of breast cancer (BC) patients undergoing preoperative lymphoscintigraphy and sentinel lymph node biopsy (SLNB) with receptor-targeted radiotracer, Tc-99m tilmanocept (Lymphoseek; Cardinal Health). Our protocol was a 2- to 2.5-hour window from injection to node detection for lumpectomy with SLNB, with 2 to 3 cases per surgical day. We wanted to evaluate if a change in radiotracer would change efficiency metrics.
Materials and Methods
Tc-99m tilmanocept injections were performed by one of several radiologists in nuclear medicine. The team tracked time on a card that traveled with the patient. A nuclear medicine technologist recorded the patient’s self-reported pain level immediately after injection on a scale of 1 (no pain) to 10 (maximum pain). In the first week, the trial duplicated existing time protocols (2 hours from injection to operating room [OR] node detection). The next phase determined how quickly the team could detect a signal. In week 2, the time between injection of the tracer and node detection was 1 hour. In week 3, that time was reduced to 30 minutes and results were evaluated.
Across subjects with BC evaluated in the series (n = 8; Table), the mean time between injection and visualization of nodes was less than 20 minutes. The total time in the OR was reduced by 68.4 ± 8.6 minutes relative to previous experience with filtered Tc-99m sulfur colloid (FSC). The authors were able to detect the node(s) in each timeframe and with no change in signal intensity. In addition, patients consistently scored their pain levels between 1 and 2 out of 10.
These case studies with Tc-99m tilmanocept displayed short wait in nuclear medicine, short procedure times, and low patient-reported injection pain. We also noted specific signal intensity and high accuracy in detecting nodes with rapid injection site clearance and high patient satisfaction. As a result, Mercy Medical Center adopted Tc-99m tilmanocept using a 30-minute injection protocol for SLNB procedures. Morning surgeries start 2 hours earlier, allowing us to add 3 surgical cases per week.