Background: Preoperative injection of radiocolloid before a sentinel lymph node (SLN) biopsy is painful for patients with breast cancer. Injection after anesthesia eliminates this discomfort but allows less time for radiocolloid migration. Our goal was to validate the efficacy of intraoperative injection.
Methods: In this retrospective study of prospectively collected data, patients underwent periareolar dermal injection of technetium sulfur colloid. Patients in the preoperative injection (PO) group were injected by radiologists in the breast imaging center. Patients in the intraoperative injection (IO) group were injected by surgeons after induction of anesthesia. Consecutive cases were evaluated for radioactive "hotspots," time elapsed before incision, number of SLNs removed, number of positive SLNs, and percentage of positive biopsies.
Results: Two hundred fourteen breasts were evaluated (PO = 102; IO = 112). The mean time from injection to incision was significantly shorter by 107 minutes for the IO group. There were no differences in the percentage of positive biopsies (PO: 20.6%; IO: 19.6%; P = 0.863), the number of SLNs removed (PO: 3.3; IO: 3.0; P = 0.091), or the number of positive SLNs (PO: 1.4; IO: 1.4; P = 0.657).
Conclusions: There are no significant differences in the principal results of SLN biopsy between PO and IO injection methods. Dermal radiocolloid injection after induction of anesthesia seems to be an oncologically sound procedure and may be a preferable technique.