Lymphoscintigraphy and sentinel node localization in breast cancer patients: A comparison between 1-day and 2-day protocols

The purpose of this study was to compare the results of isotope injection t he morning of surgery (1-d protocol) with isotope injection the day before surgery (2-d protocol) in patients having sentinel lymph node (SLN) biopsy for breast cancer. Methods: The 1-d (protocol 1) and 2-d (protocol 2) proto cols included 514 and 152 patients, respectively, treated contemporaneously by surgeons experienced with the SLN biopsy technique. All had preoperativ e lymphoscintigraphy (LSG) and SLN biopsy using both blue dye and Tc-99m-su lfur colloid. All patients had a single-site intradermal injection of unfil tered Tc-99m-sulfur colloid in 0.05 mt normal saline: 3.7 MBq (0.1 mCi) on the morning of surgery for protocol 1 and 18.5 MBq (0.5 mCi) on the afterno on before surgery for protocol 2. Results: The patients in protocols 1 and 2 were comparable in terms of age, tumor size, tumor location, histologic t ype, node positivity, and frequency of a previous surgical biopsy. Comparin g protocols 1 and 2, early (30 min) LSG images found the SLN equally often (69% vs. 68%). Isotope identified the SLN equally often at surgery (93% vs. 97%) as did isotope plus dye (98% vs. 99%). A comparable number of SLNs wa s found (2.5 vs. 2.8 per axilla), and the concordance between isotope and d ye in the SLN was also comparable (97% vs. 95%). Late LSG images (at 2 h, p ossible only for protocol 2) identified the SLN in significantly more patie nts compared with early images (86% vs. 68%). Conclusion: With unfiltered T c-99m-sulfur colloid injected intradermally, the results of SLN biopsy unde r the 1-d and 2-d protocols are virtually identical. A 2-d protocol allows increased efficiency in scheduling, both for nuclear medicine physicians an d for the operating room, with no compromise in the effectiveness of SLN ma pping.