Assessment of the interface between retroperitoneal fat infiltration of pancreatic ductal carcinoma and the major artery by multidetector-row computed tomography: surgical outcomes and correlation with histopathological extension.

Background: Precise assessment of retroperitoneal invasion is clinically important to allow the achievement of negative margin resections.

Methods: The clinical records of 132 patients who underwent macroscopic curative pancreaticoduodenectomy for invasive ductal carcinoma of the pancreas between 2004 and 2008 were retrospectively examined. The clinicopathological factors, including retroperitoneal fat infiltration classified into four groups by multidetector-row computed tomography (MDCT), were analyzed. The relationship between the grade of retroperitoneal fat infiltration and surgical outcomes, as well as various histopathological factors, was also investigated.

Results: The 5 year survival rate was 55.6 % for grade 0 infiltration (n = 8), 38.7 % for grade 1 (n = 54), 16.4 % for grade 2 (n = 49), and 0 % for grade 3 (n = 21). There were significant differences in survival in each group. Extrapancreatic nerve invasion and the surgical margin status were significantly associated with retroperitoneal fat infiltration demonstrated on MDCT. According to the grading classification among the 43 patients with pathological portal vein invasion, the 5 year survival rate was 45.9 % for patients with grade 1, which was significantly better survival that those with grade 2 (P = 0.007).

Conclusion: The grading criteria for retroperitoneal fat infiltration may be useful as a predictor of survival after pancreaticoduodenectomy for pancreatic head carcinoma. Pancreaticoduodenectomy with portal vein resection could provide favorable survival in patients with grade 1 retroperitoneal fat infiltration, even if histopathological portal vein invasion is present.