Intraoperative injection of subareolar or dermal radioisotope results in predictable identification of sentinel lymph nodes in breast cancer.

OBJECTIVE: Our objective is to prove that injection of technetium-99m (Tc99) sulfur colloid in a subareolar manner, after induction of anesthesia, is a safe and effective technique for sentinel lymph node identification in breast cancer patients.
INTRODUCTION: Preoperative injection of Tc99 and lymphoscintigraphy is standardly performed before sentinel lymph node biopsy (SLNB) for breast cancer. Blue dye is often used to help guide and confirm the localization but tattoos the breast. This method is limited because of painful injections, variable identification rates, added costs and unnecessary scheduling delays. We hypothesized that intraoperative injection alone by the surgeon of dermal or subareolar Tc99 is practical for the identification of sentinel lymph node in breast cancer.
METHODS: This is a prospective single institution study that was approved by our institutional review board. All patients with operable breast cancer that were eligible for a SLNB from October 2002 to October 2010 were included in our study population. After induction and before sterile preparation of the operative field 1 mCi of Tc-99 unfiltered was administered by a subareolar injection. In patients where the scar was in the periareolar region or in the upper outer quadrant a dermal injection using 0.25mCi was used. Confirmatory Lymphazurin was also injected early on in this series but became unnecessary later in the study. Site and type of injection, injection time, incision time, and extraction time along with other factors for the purposes of the study were recorded. Data comparing injection preoperative and intraoperative were collected.
RESULTS: Six hundred ninty-nine patients were accrued for a SLNB with an average age 57.1 ± 12.8 (range 24-92). Seventy-six patients underwent 2 SLNB procedures for a total of 775 intraoperative Tc-99 injections. Six patients underwent intraoperative dermal injection with Tc-99. The average dose of Tc-99 administered was 1.157 ± 0.230 mCi. The sentinel node was localized in 98.6% of the cases (419/425) of subareolar radiotracer alone, 94.8% (326/344) in dual injection and 100% (6/6) in dermal injection. Average time from injection to incision was 41.20 ± 29.56 minutes for radiotracer injection in subareolar region only. For dermal injections it was 40.83 ± 39.64 minutes. For patients with dual injection of Lymphazurin and radiotracer it was 31.74 ± 24.86 minutes. The average ex vivo count was 6474 ± 8395 for dermal injection, 28,250 ± 69,932 for Tc-99 subareolar injection, and 35,501 ± 97,753 for dual subareolar injection. Intraoperative radiotracer alone incurred a charge of $189.00; Lymphazurin blue dye added $591.40, whereas preoperative injection had a charge of $1257.06 associated with imaging, injection, and interpretation of images.
CONCLUSION: Intraoperative injection of Tc99 alone with a subareolar or dermal injection technique rapidly localizes the sentinel node in breast cancer, is an oncologically sound procedure, is cost effective and facilitates operative room time management.