Role of intraoperative cytology combined with histology in detecting continuous and skip type intraductal cancer existence for intraductal papillary mucinous carcinoma of the pancreas

BACKGROUND. Intraductal papillary mucinous neoplasm (IPMN) is a recently discovered pancreatic tumor that has continuous or discontinuous (skip) lesions. Recent reports suggest a higher frequency of cancer recurrence in the remnant pancreas after surgical resection of IPMN. It is therefore important to precisely detect intraductal cancer extension and skip lesions when resecting IPMN. METHODS. Both intraoperative histologic examination of the surgical margin and cytologic examination of the pancreatic juice from each pancreatic segment (head, body, or tail) were performed on 43 IPMN patients. In addition to the preoperatively planned resection, 1 or 2 pancreatic segment(s) were additionally resected if the pancreatic juice tested positive in cytology. When a surgical margin was positive hut the cytology in the remaining segment was negative, a subsegment (2-cm slice in width) was additionally resected until a negative margin was confirmed. RESULTS. Twenty-five patients (58%) demonstrated negative results in both histology and cytology obtained from the segment(s) that were not initially intended to be removed. In contrast to the preoperative estimation, 5 patients were found to have a positive surgical margin and negative cytology, 5 patients demonstrated a negative surgical margin and positive cytology, and 8 patients demonstrated a positive surgical margin and positive cytology. Investigations of the resected specimens revealed that 8 patients (19%) had skip lesions in addition to the main lesion. Logistic regression analysis revealed that patients with a dilated main pancreatic duct, or those with cancerous lesions in the main tumors, were at high risk for positive histology and/or cytology. CONCLUSIONS. Using intraoperative frozen-section histology and pancreatic juice cytology, 18 out of 43 patients in the current study (42%) required additional resection of the pancreas. A necessary and sufficient range of resection should be determined by intraoperative examination.