Intraoperative radioisotope injection for sentinel lymph node biopsy

Background: Preoperative injection of technetium-99 m sulfur colloid (Tc-99) in the Nuclear Medicine Department for localizing sentinel lymph nodes (SLNs) can be extremely painful for the patient. The difficulties in scheduling and the delay in starting surgery can be frustrating for the patient and the surgeon. We hypothesized that intraoperative injection facilitated by the subareolar technique would obviate the problems associated with preoperative injection. Methods: We performed an institutional review board-approved prospective study of patients with operable breast cancer who were candidates for an SLN biopsy from October 2002 to January 2006 at our institution. After induction of general anesthesia, patients underwent a subareolar injection of 1 mCi Tc-99 unfiltered and blue dye. Data comparing preoperative cost were collected. Results: A total of 236 patients had 252 intraoperative SLN procedures. The mean patient age was 57.3 (range, 24-88) years. The mean ± standard deviation time from injection to incision was 25.5 ± 16.2 minutes. Identification rate was 96%, and the number of SLNs identified per patient was 1.6 ± .8. The count of SLN was 60,313 ± 134,692 with 20% SLN positivity. Tumor staging distribution was standard staging terminology for an in situ cancer (Tis) = 17 with 0% (+) SLN, T1 = 115 with 11% (+) SLN, T2 = 56 with 29% (+) SLN, T3 = 19 with 37% (+) SLN, and T4 = 4 with 50% (+) SLN. Maximum exposure to the surgeon was well below maximum, at 100 μSV/mo. Preoperative injection had an additive charge of $1325 associated with it for imaging, injection, and interpretation of images by physician. Conclusion: Intraoperative subareolar injection of Tc-99 localizes the SLN and avoids the pain, vasovagal events, delays, and cost associated with preoperative procedure.