Rapid immunohistochemical detection of lymph node micrometastasis during operation for upper gastrointestinal carcinoma

Background: The intraoperative diagnosis of lymph node micrometastasis (LNM) may help guide the area of appropriate lymph node dissection. This study aimed to evaluate the rapid immunohistochemical detection of LNMs using frozen sections during operation for gastro-oesophageal cancer. Methods: Rapid immunostaining with anticytokeratin (AE1/AE3) antibody was compared with conventional immunostaining. A total of 2 10 lymph nodes obtained from 47 patients with oesophageal squamous cell carcinoma and from 32 with gastric adenocarcinoma were examined during operation. Lymph nodes were frozen, sectioned, and examined by histological and immunohistochemical methods. Results: It took 30 min to complete the rapid immunostaining procedure; the expression of cytokeratin by rapid immunostaining was similar to that by conventional immunostaining. The incidence of lymph node metastasis detected by histological and immunohistochemical examination was 17 and 23 per cent respectively. LNM was solely detected in 12 lymph nodes by immunostaining: three micrometastases and nine with tumour cell microinvolvement. Conclusion: Intraoperative rapid immunostaining is a simple and useful technique for detecting LNMs. Further study should investigate the role of rapid immunostaining during cancer surgery to select appropriate areas for lymphadenectomy.