title: Precise pathologic examination decreases the false-negative rate of sentinel lymph node biopsy in gastric cancer.
abstract: BACKGROUND
  Gastric cancer has been identified as a target for sentinel lymph node (SLN) navigational surgery. Although accurate evaluation of SLNs is essential for applying the SLN concept to gastric cancer surgery, there is no standardized pathologic examination protocol for SLNs in gastric cancer.
  
  
  METHODS
  A total of 231 SLNs from 69 patients with cT1-2, N0 gastric cancer were prospectively examined in this study. During the operation, SLNs were sliced at 2-mm intervals, and frozen sections were analyzed by hematoxylin and eosin (HE) staining in 35 patients or HE staining with rapid immunohistochemistry (IHC) for pancytokeratin (CK) in 34 patients. HE staining and CK IHC were performed postoperatively on each remaining SLN. Non-SLNs were evaluated with 2 levels of HE slides and 1 CK IHC.
  
  
  RESULTS
  Of 35 patients, metastasis was identified in 10 patients by intraoperative HE staining, and in 12 patients by postoperative HE staining and CK IHC. Two patients had isolated tumor cells (ITCs) detectable by postoperative CK IHC; these patients had non-SLN metastasis. We enrolled another 34 patients and examined 147 SLNs by frozen HE and rapid IHC. In this cohort, 26 patients with negative SLNs by intraoperative examination did not have non-SLN metastasis even after deeper sectioning and CK IHC of non-SLNs (sensitivity, 100%; false negative value, 0%).
  
  
  CONCLUSIONS
  Our study indicated that precise and detailed intraoperative examination decreases the false-negative rate of SLN biopsy. ITCs in SLNs should not be overlooked, and rapid IHC can be helpful for detecting ITCs intraoperatively.
authors: Department of Pathology, Seoul National University Bundang Hospital, Seongnam, Korea.
authors: Hye Seung
authors: HS
authors: Lee
authors: Hee Eun
authors: HE
authors: Lee
authors: Do Joong
authors: DJ
authors: Park
authors: Young Soo
authors: YS
authors: Park
authors: Hyung-Ho
authors: HH
authors: Kim
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001801:Blood Stains; D005188:False Negative Reactions; D005260:Female; D005629:Frozen Sections; D006416:Hematoxylin; D006801:Humans; D007150:Immunohistochemistry; D007432:Intraoperative Period; D007633:Keratins / Q000032:analysis; D008198:Lymph Nodes / Q000737:chemistry / Q000473:pathology; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D021701:Sentinel Lymph Node Biopsy; D018571:Sentinel Surveillance; D013274:Stomach Neoplasms / Q000473:pathology* / Q000601:surgery*
chemical_list: D007633:Keratins; D006416:Hematoxylin