Immunohistochemical evaluation for intraoperative rapid pathological assessment of the gastric margin

In patients undergoing surgery for gastric cancer, as the resection area is difficult to define preoperatively, we define the resection area by intraoperative rapid pathological assessment of the resected margin. In some patients, however, the result of postoperative assessment of a permanent section differs from the result obtained intraoperatively. In this study we explored methods of improving the accuracy of intraoperative pathological assessment. Of the patients who underwent surgery for gastric cancer at Takarazuka Municipal Hospital, between April 2000 and July 2001, intraoperative pathological assessment of the resection margin was performed in 34 because it could not be accurately defined preoperatively. The intraoperative assessment consisted of touch smear cytological examination and hematoxylin and eosin (HE) and cytokeratin (CK) histological examination. The time required to perform cytological examination and HE and CK immunohistochemistry by this modified method, which uses an ENVISION Kit/HRP, was approximately 20 minutes for each procedure. Touch smear cytological examination gave false positive results in 3 of 34 patients (8.8%). Of the 14 patients preoperatively diagnosed with signet-ring cell carcinoma, intraoperative HE histological analysis yielded a false negative result in one (7.1%). The results of CK histological assessment of these patients were all consistent with those of postoperative examination of permanent sections. Of the 20 patients preoperatively diagnosed with non-signet-ring cell carcinoma, HE analysis yielded a false negative result in one (5%). The results of CK histological assessment of these patients were all consistent with those of postoperative examination of permanent sections. Our modified CK staining method with the ENVISION Kit/HRP allows intraoperative pathological assessment to be performed accurately and rapidly. This method is more useful than HE immunohistochemistry for the assessment of resected gastric margins.