The value of combined peritumoral and subdermal injection techniques for lymphoscintigraphy in detection of sentinel lymph node in breast cancer

PURPOSE: The aim of this study was to evaluate the success rate of combined peritumoral and subdermal injection techniques based on our previous experience on different injection techniques for lymphoscintigraphy. PATIENTS AND METHODS: Fifty-nine women with early breast cancer (mean tumor size, 20.5 mm) were prospectively studied. On the morning of the operation, each patient had 2 injections, one peritumoral (PT) medial to the lesion and one subdermal (SD) into the skin over the tumor quadrant. Each injection consisted of 20 MBq (540 mCi) Tc-99m rhenium sulfide colloid. Early dynamic and delayed static images were obtained up to 4 hours after injections. An intraoperative gamma probe was used to explore the axillary sentinel lymph nodes (SLN). All surgical specimens were evaluated histopathologically. RESULTS: Forty patients had breast-preserving surgery and 19 had modified radical mastectomy. Thirty-eight patients had axillary dissection. All but 4 patients showed axillary lymphatic drainage. Twelve of 59 patients (20%) showed extraaxillary drainage with lymphoscintigraphy. Combined injection technique yielded a 93.2% success rate in detecting axillary SLN. In 2 of 4 patients with no drainage on lymphoscintigraphy, intraoperative gamma probe revealed SLN during the surgery. Twenty patients (33%) had positive axillary lymph nodes. In 14 of them, the SLN was the only positive node. A false-negative rate was found 1.6% (one of 59 patients). CONCLUSION: This results suggest that a combination of both PT and SD techniques increases the success rate of visualization SLN and enhances the visualization of extraaxillary nodes for further treatment planning.