Diagnostic Performance of EUS-FNA for Pancreatic Lesions at Tertiary Centers in Iran Without Rapid On-Site Evaluation.

[BACKGROUND] Endoscopic ultrasonography-guided fine needle aspiration (EUS-FNA) is widely used for diagnosing pancreatic neoplasms, contributing to improved therapeutic strategies for pancreatic cancer. This aim of this study is to evaluate the diagnostic utility, sample adequacy, and limitations of EUS-FNA cytology for pancreatic lesions. These were further confirmed after surgical resection and histopathological evaluation.

[METHODS] We retrospectively included patients referred to two Teaching Hospitals in southern Iran for EUS-FNA due to suspected pancreatic cancer, who later underwent surgical resection or biopsy and eventually had a histopathological confirmed diagnosis. The cytological smears from EUS-FNA were compared with the final histology reports to assess diagnostic performance.

[RESULTS] Thirty patients were included in the final analysis. EUS-FNA cytology showed sensitivity of 90.00% [95% CI: 68.30, 98.77], specificity of 80.00% [95% CI: 44.39, 97.48], negative predictive value (NPV) of 80.00% [95% CI: 50.89, 93.92], positive predictive value (PPV) of 90.00% [95% CI: 72.09, 96.91], and overall accuracy of 86.67% [95% CI: 69.28, 96.24]. Two false-positive diagnoses (hydatid cyst and chronic pancreatitis) and two false-negative diagnoses (malignancies attributed to sampling errors) were observed. Immunohistochemical tests confirmed 8 out of 9 diagnoses made by cytology. Notably, all EUS-FNA samples provided adequate material for conclusive diagnosis.

[CONCLUSION] These results support the high importance of the diagnostic performance of EUS-FNA on solid pancreatic lesions, even without Rapid On Site Evaluation (ROSE), given that the sample is of adequate size for testing. Despite a few false negative and false positive diagnoses, EUS-FNA should be considered the first-line diagnostic tool for pancreatic lesions assessment.