Utility of endoscopic ultrasound‐guided fine‐needle aspiration in the diagnosis and staging of colorectal carcinoma

The objective of this study is to assess the utility of endoscopic ultrasound‐guided fine‐needle aspiration (EUS‐FNA) in the diagnosis and staging of colorectal cancer. The study includes patients who underwent EUS‐FNA at our institution for staging of colorectal carcinoma or for evaluation peri‐rectal masses or distal metastases from August 2000 to November 2010. We assessed the frequency with which EUS‐FNA procedure confirms the diagnosis of malignancy and the percent of cases in which it modifies staging of colorectal carcinoma. Using histology as a reference standard, we also assessed the diagnostic performance. We identified 79 cases of EUS‐FNA from 77 patients, mean (SD) age of 60 (12.5), 44 males. Twenty‐seven (34%) aspirates were from patients with primary rectal/peri‐rectal masses, 15 (19%) were from patients with suspected regional lymph node metastasis, and 37 (47%) were cases of suspected of distal metastasis. All lesions were clinically suspicious for primary or metastatic colorectal carcinoma. On cytologic examinations, 43 (54%) cases were confirmed as malignant, 6 (8%) were benign neoplasms, 4 (5%) were suspicious for malignant neoplasm, 2 (3%) showed atypical cells, and the rest 24 (30%) were negative for neoplasms. Fourteen of 27 (52%) of the local rectal masses were confirmed as colorectal carcinoma. Eleven of 15 (73%) regional lymph nodes were positive for metastasis—all, but two of these metastases, were of colorectal origin. Twenty of 37(54%) distal lesions were metastatic neoplasms and 15 of those were colorectal in origin. Diagnosis of primary colorectal carcinoma was confirmed in 52% of the clinically suspicious primary lesions and in 42% regional or distal metastatic lesions. Using histology as a reference standard in 27 of 79 (29%) cases, we calculated an overall sensitivity, specificity, and positive and negative predictive values (C.I) of EUS‐FNA of 89% (74–100%), 79% (50–100%) 89% (74–100%), and 79% (51–100%). EUS‐FNA is useful for assessing primary and metastatic colorectal lesion. This technique improves staging of suspected nodal or distant metastases. Diagn. Cytopathol. 2013;41:1031–1037. © 2011 Wiley Periodicals, Inc.