TNM staging of pancreatic carcinoma using helical CT

The purpose of this study was to determine the accuracy of helical CT scanning in predicting the stage of carcinoma of the exocrine pancreas using TNM staging guidelines and in predicting resectability of carcinoma of the exocrine pancreas.

Twenty-six patients with proven adenocarcinoma of the pancreas underwent uniphasic or biphasic helical CT scanning. Two observers unaware of the patient's surgical stage evaluated the CT examinations using the TNM system (with specific assessment and description of disease sites). In addition, the two observers rated confidence of nonresectability using a 5-point scale (ranging from 1, definitely resectable, to 5, definitely not resectable). Observer results and preoperative interpretations were compared with surgical findings.

Nineteen of 26 patients had nonresectable disease. The combined observer scores showed correct determination of T stage in 77% of patients, of N stage in 58%, and of M stage in 79%. The overall accuracy in determining lack of resectability was 96% and 84% for the two observers. All errors in determining resectable versus nonresectable disease occurred when the observer was not maximally confident of his or her diagnosis.

Helical CT is an effective screening technique for assessing T and M stages of pancreatic carcinoma. However, helical CT is poor at detecting regional lymph node involvement. In patients with equivocal T-stage findings (such as questionable venous involvement), other studies such as endoscopic sonography may be of value.