Negative predictive value of positron emission tomography/computed tomography in patients with a clinical suspicion of pancreatic cancer

The aim of this study was to determine the negative predictive value of positron emission tomography (PET)/computed tomography (CT) in patients with lesions suggestive of pancreatic cancer. A retrospective review from January 2005 to August 2008 of all patients who underwent a PET/CT to evaluate a lesion suggestive of pancreatic cancer based on prior imaging. One hundred eighty-four patients underwent PET/CT, of which 60 patients had a negative PET scan. Of these 60 patients, 56 patients (30 women, 26 men) had endoscopic ultrasound-guided fine-needle aspiration or surgical pathology for clinical correlation. The Fisher exact test was used for statistical analysis. The negative predictive value of PET/CT was 75%. Eighteen patients had a benign lesion, 24 patients had a premalignant lesion, and 14 patients had a malignant lesion. In the cystic group, 72.4% of the PET/CT-negative lesions were premalignant compared with the solid group that was only 5.9%. This was in contrast to the solid group, where 64.7% was malignant versus 6.9% in the cystic group. Two of 14 patients with malignancy had metastatic disease. The negative predictive value of PET/CT in pancreatic lesions suggestive of pancreatic cancer was 75%. A negative PET/CT does not exclude pancreatic cancer, and further workup of these PET-negative lesions is warranted.