Definition and recurrence or metachronous high risk lesion

Tumor recurrence detected with CT or MRI was confirmed by biopsy if possible. New tumors including remnant pancreas, resection margin, peri-pancreatic area, or systemic metastasis were included recurrences. However, recurrences resulting from malignancies in other organs were not included in the analysis. Remnant pancreas were thoroughly examined, and the occurrence of new IPMNs was monitored. Metachronous HRL was defined by all newly occurring IPMNs in the remnant pancreas except resection margin, which was examined histologically as HGD or IC. In non-resected cases, HRLs were diagnosed by cytological examination or radiological findings, which strongly suggested malignancy according to IAP guidelines.^1,2,4