Resection margins in pancreatic cancer.

The R1 rate and prognostic significance of microscopic margin involvement differ consistently between published series. This divergence results from a lack of consensus regarding various aspects of margin status assessment. Central to the controversies is the lack of clarity about what 'R1' exactly stands for. The current UICC definition--residual microscopic tumor--is possibly too general and invites divergent interpretations. Adherence to different diagnostic criteria for microscopic margin involvement and divergent terminology for the various margins of pancreatoduodenectomy specimens add to the confusion. Furthermore, recent studies demonstrated that the dissection technique and extent of tissue sampling influence the accuracy of margin assessment. Axial specimen slicing, extensive tissue sampling, and multicolored margin inking result in a significantly higher, more accurate R1 rate than when using traditional grossing techniques. Only when international consensus on these various aspects is reached will pathology data on margin involvement be reliable and can multicenter clinical trials produce compelling evidence that allows improved pancreatic cancer treatment.