Enhanced Discrimination of Malignant from Benign Pancreatic Disease by Measuring the CA 19-9 Antigen on Specific Protein Carriers

The CA 19-9 assay detects a carbohydrate antigen on multiple protein carriers, some of which may be preferential carriers of the antigen in cancer. We tested the hypothesis that the measurement of the CA 19-9 antigen on individual proteins could improve performance over the standard CA 19-9 assay. We used antibody arrays to measure the levels of the CA 19-9 antigen on multiple proteins in serum or plasma samples from patients with pancreatic adenocarcinoma or pancreatitis. Sample sets from three different institutions were examined, comprising 531 individual samples. The measurement of the CA 19-9 antigen on any individual protein did not improve upon the performance of the standard CA 19-9 assay (82% sensitivity at 75% specificity for early-stage cancer), owing to diversity among patients in their CA 19-9 protein carriers. However, a subset of cancer patients with no elevation in the standard CA 19-9 assay showed elevations of the CA 19-9 antigen specifically on the proteins MUC5AC or MUC16 in all sample sets. By combining measurements of the standard CA 19-9 assay with detection of CA 19-9 on MUC5AC and MUC16, the sensitivity of cancer detection was improved relative to CA 19-9 alone in each sample set, achieving 67–80% sensitivity at 98% specificity. This finding demonstrates the value of measuring glycans on specific proteins for improving biomarker performance. Diagnostic tests with improved sensitivity for detecting pancreatic cancer could have important applications for improving the treatment and management of patients suffering from this disease

Ultrasound-guided percutaneous fine-needle aspiration of solid pancreatic neoplasms: 10-year experience with more than 2,000 cases and a review of the literature

OBJECTIVES:To evaluate the diagnostic accuracy and complication rate of percutaneous ultrasound-guided fine-needle aspiration (US-FNA) of solid pancreatic neoplasms through the analysis of 10-year experiences of two centres.METHODS:Clinical, radiological and pathologic data of 2,024 patients with solid pancreatic masses who underwent US-FNAs were retrospectively evaluated. Indications for aspiration were: unresectable lesions before neo-adjuvant therapy; doubtful imaging findings; and suspicion of uncommon neoplasms with prognostic or therapeutic implications such as metastases or lymphoma. US-FNAs were performed using aspiration needles with a cytopathologist present in centre 1. In centre 2, cytologic samples were collected with Chiba needles and separately evaluated by a cytopathologist.RESULTS:US-FNA had a diagnostic sample rate of 92.2 % (centre 1: 95.9 %; centre 2: 87.2 %). US-FNA repetition after non-diagnostic samples provided a diagnosis in 86.3 % of cases. Sensitivity, specificity, positive and negative predictive values, and accuracy were 98.7 %, 100 %, 100 %, 75.5 %, and 98.7 %, respectively. The complication rate was 0.8 %.CONCLUSIONS:Percutaneous US-FNA is a sensitive, accurate and safe method for the invasive diagnosis of solid pancreatic neoplasms. The use of aspiration needles and the on-site presence of a cytopathologist may lead to a high rate of diagnostic samples, thus reducing the need for US-FNA repetition.KEY POINTS:• Percutaneous ultrasound-guided fine-needle aspiration of pancreatic neoplasms is sensitive and accurate. • The short-term complication rate of percutaneous ultrasound-guided fine-needle aspiration is low. • Technical aspects may influence the rate of diagnostic samples