CT criteria for venous invasion in patients with pancreatic head carcinoma.

Abstract

The purpose of the study was to evaluate CT criteria for venous invasion in patients with potentially resectable carcinoma of the pancreatic head, with surgical and histopathological correlation. In 113 patients evaluated with spiral CT for suspected pancreatic head carcinoma, several CT criteria for venous invasion were scored prospectively for the portal vein (PV) and the superior mesenteric vein (SMV): length of tumour contact with PV/SMV (0 mm, < 5 mm, > 5 mm); circumferential involvement of the vein (0 degree, 0-90 degrees, 90-180 degrees, > 180 degrees); degree of stenosis; irregularity of the vessel margin; and tumour convexity towards vessel. 65 patients underwent surgery. Pancreatic head carcinoma was proven and pathology of the vascular margin was obtained in 50 of these patients. CT findings for single and combined criteria were correlated with pathology in these 50 patients, 30 of whom showed venous ingrowth. Invasion was found in all cases with SMV narrowing (n = 7), PV contour involvement > 90 degrees (n = 6), PV narrowing (n = 5) and PV wall irregularity (n = 3). The vascular ingrowth rate was 88% (15/17) for tumour concavity towards the PV or SMV. Poor predictors of ingrowth were length of tumour contact with PV > 5 mm (78% ingrowth, 14/18) and contour involvement of the SMV > 90 degrees (83% ingrowth, 10/12). Absence of vascular ingrowth could not be predicted in 100%. In conclusion, CT criteria can predict a high risk of invasion in potentially resectable tumours. Narrowing of the SMV and the PV seems the most reliable criterion, as well as circumferential involvement of the PV > 90 degrees. The best combination of criteria was tumour concavity with circumferential involvement > 90 degrees (sensitivity 60% and positive predictive value 90%).

Value of CT criteria in predicting survival in patients with potentially resectable pancreatic head carcinoma

“…There were six patients with radically resected tumors that were regarded as being locally unresectable on CT. CT also underestimated tumor positive microscopic margins: in 50% of tumors predicted as locally resectable by CT, resection margins were shown to be tumor positive. These findings are similar to a previous study comparing CT findings and tumor invasion of vessels: a high risk for invasion can be demonstrated, but in many patients, microscopic invasion is underestimated by CT [11]. It is questionable whether the predictive value of 83% for a positive margin will be sufficient to influence the decision on surgical exploration.…”

“…This was based on a previous study [13]. Portal vein involvement of >90 degrees also has a high predictive value for invasion [11] and Furukawa showed that portal vein involvement of >90 degrees is associated with a poor survival (33%, 1-year survival) [27]. Indeed in the present study, involvement of >90 degrees had significant prognostic value.…”

“…A major problem is the detection of local tumor extension and vascular invasion, which is present in about 50% of surgical patients [7,8,11,13,29,30]. Depending on the criteria used, CT can predict vascular invasion with 100% predictive value, but with a low sensitivity [11].…”

“…Depending on the criteria used, CT can predict vascular invasion with 100% predictive value, but with a low sensitivity [11]. Therefore a large proportion of patients cannot be excluded from surgical exploration.…”

Neoadjuvant chemoradiotherapy has a potential role in pancreatic carcinoma

“…Resectability of tumours is difficult to assess. Although criteria have been developed for assessment by preoperative modern imaging techniques, such as computed tomograpy scan or magnetic resonance imaging [Phoa et al 2000[Phoa et al , 2005, many still decide during exploratory laparotomy whether or not to continue with a resection. This is mainly dependent on attitudes towards performing a resection of the portal and mesenteric veins and the mesenteric artery.…”