title: Effectiveness of delayed 2-day lymphoscintigraphy on sentinel lymph node detection in patients with breast cancer with negative early lymphoscintigraphy.
abstract: OBJECTIVE
  Most centers perform lymphoscintigraphy for the detection of sentinel lymph node (SLN) in patients with breast cancer within 2 hours after radiotracer injection. However, the interval between the injection of the radiotracer and surgery may not be long enough. In this study, we evaluated the effectiveness of delayed imaging (more than 15 hours) for SLN detection in patients with negative early images.
  
  
  METHODS
  We retrospectively analyzed a database of 401 patients with breast cancer referred for SLN detection. On the day before surgery, lymphoscintigrams were obtained at 30-minute intervals until SLN was detected or 120 minutes. In those patients who failed to localize SLN on the early images, delayed imaging was performed the next morning.
  
  
  RESULTS
  Twenty-seven (6.7%) patients failed to show SLN on the early images. In the 27 patients, delayed imaging was available for 14 patients but not for 13 patients resulting from the tight time schedule for surgery. Of the 14 patients with delayed images, SLNs were successfully harvested in 10 patients (71.4%) at surgery. In contrast, in the 13 patients who lacked delayed images, SLN was only harvested in one case (7.7%) at surgery. The intraoperative detection rate for SLN was significantly higher in the 14 patients with delayed images than that in the 13 patients without delayed images.
  
  
  CONCLUSIONS
  Two-day delayed imaging is significantly useful to increase the rate of localizing SLN at surgery in patients with a negative early image.
authors.affiliation: Department of Nuclear Medicine, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: Hsin-Yi
authors.initials: HY
authors.lastname: Wang
authors.forename: Chien-Chung
authors.initials: CC
authors.lastname: Tsai
authors.forename: Guang-Uei
authors.initials: GU
authors.lastname: Hung
authors.forename: Wan-Yu
authors.initials: WY
authors.lastname: Lin
mesh_terms: D001943:Breast Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000175:diagnosis*; D011237:Predictive Value of Tests; D011877:Radionuclide Imaging / Q000379:methods*; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D021701:Sentinel Lymph Node Biopsy; D013671:Technetium Tc 99m Sulfur Colloid; D013997:Time Factors
chemical_list: D019275:Radiopharmaceuticals; D013671:Technetium Tc 99m Sulfur Colloid