Resectable pancreatic head adenocarcinoma: Is R0 resection an illusion? Genetic evaluation of venous resection margin affirmed unrecognized disease.

PURPOSE

To assess the K-ras gene mutation in the histologically negative venous margin of a pancreaticoduodenectomy (PD) specimen and its impact on survival.

METHOD

From 2007 to 2010, 22 patients underwent R0 PD for resecable pancreatic adenocarcinoma. All specimens were stained and the portal vein (PV) bed was identified by blue ink; a 2mm sample (including the blue ink) was cut from a microscopic free-tumor block. DNA was extracted and assessed by quantitative real time polymerase chain reaction to detect the K-ras gene mutation. Twelve specimens (55%) (kras+ group) were identified with a K-ras mutation in the venous margin resection, and 10 specimens (kras- group) did not have K-ras mutation detected in the venous margin resection.

RESULTS

The two groups were comparable. Overall 3years survival of patients of kras+ group versus patients of kras- group was 0 and 17% (P=0.03), respectively. Median survival time of patients of kras+ group versus patients of kras- group was 16months vs 25months (P=0.04; 95% confidence interval [1,11-1,88]), respectively.

CONCLUSION

Genetic evaluation of venous resection margin affirmed unrecognized disease with strong impact on survival in more than 50% of patients with histologically R0 resection.