[Standardization of pancreatic cancer specimen pathological examination]

The frequency of R1 resections for pancreatic cancer in studies where a non-standardized protocol of pathological evaluation of the specimen is used varies from 17 to 30%. The aim of our study is to apply the standardized (so-called Leeds) protocol of resected pancreatic specimen pathological examination, and to evaluate the frequency of R1 resections for pancreatic cancer using this new protocol.

Ninety-one patients who underwent pancreatoduodenectomy for pancreatic cancer were included in the study. This group was divided into two subgroups: patients examined by the Leeds protocol (n=20) and those examined by a non-standardized pathological protocol (n=71). The R1 resection rate was evaluated separately in each group. The positivity rate of every individual resection margin was specified in the Leeds protocol group. The correlation of R1 resection rate and "tumour - resection margin distance" parameter was evaluated. The tumour infiltration of peripancreatic adipose tissue was assessed in the non-standardized group.

In the Leeds protocol subgroup, R1 and R0 resection rate was 60% (12/20) and 40% (8/20), respectively. Resection line positivity rates were as follows: dorsal 45% (9/20), ventral 35% (7/20), VMS 20% (4/20), cervical 20% (4/20), AMS 15% (3/20). The correlation between the tumour - resection line distance and R1 resection frequency was the following: direct infiltration 30% R1, tumour-resection margin border 0.5 mm 50% R1, 1mm 60%, 1.5 mm 75% R1, 2 mm 80% R1, >2 mm 80% R1. If the criterion of resection line positivity ( 1mm) was set, the R1 resection rate difference between the two groups was of statistical significance. In the subgroup where the non-standardized protocol was used (n=71), R1 resection was recorded in 25 (35.2%) patients. The main cancer-positive areas were peripancreatic adipose tissue in 26.8% (19/71) of cases, and VMS, AMS or retroperitoneal line in 8.5% (6/71), respectively. R0 resection was achieved in 46 (64.8%) patients. The statistically significant (p=0.046) difference in R0 and R1 resection rates was detected (Leeds protocol and non-standardized one: R0 40.0% vs. 64.8% and R1 60.0% vs. 35.2%, respectively) in the studied groups.

The rate of R1 resections for pancreatic cancer increased in all studies, including ours, where the standardized (Leeds) protocol of pancreatic specimen pathological examination was used. The higher R1 resection rate when using the Leeds protocol is approaching to the local recurrence rate of pancreatic cancer. Therefore, the Leeds protocol can provide more realistic evaluation of local radicality of pancreatoduodenectomy and can also offer more accurate evaluation of the surgical and adjuvant therapy of pancreatic cancer.