EUS-guided fine-needle biopsy (FNB) is the standard technique for diagnosing solid pancreatic masses, offering high histologic accuracy. However, adequate tissue acquisition can still be difficult in small or technically demanding lesions. Liquid-based cytology (LBC) may serve as a complementary tool to improve diagnostic yield. This study compared the diagnostic efficacy and cytomorphologic features of 2 LBC techniques—precipitation-based SurePath and filtration-based ThinPrep—using cytologic specimens prepared from the residual fluid remaining after retrieval of core tissue from EUS-FNB specimens.

A total of 102 patients with suspected malignant pancreatic tumors who underwent EUS-guided FNB were prospectively randomized into the SurePath and ThinPrep groups in a 1:1 ratio. Cytomorphologic features and slide quality were systematically evaluated. The final diagnosis integrated the cytologic, histologic, and clinical follow-up results.

The groups had comparable baseline characteristics. Most cases (99.02%) were diagnosed as malignant, and pancreatic ductal adenocarcinoma was predominant (90.20%). SurePath demonstrated superior diagnostic accuracy (97.0% vs 83.9%, P = .002) and sensitivity (97.0% vs 83.7%, P = .002) to ThinPrep, whereas both techniques showed 100% specificity and positive predictive values. SurePath required a significantly shorter interpretation time ( P = .023). Cytomorphologically, SurePath showed more even distributions ( P < .001) and 3-dimensional clusters ( P < .001) and less cytoplasmic blurring ( P = .064). SurePath preparations also demonstrated better preservation of key diagnostic features, including conspicuous nucleoli ( P = .013), hyperchromasia ( P = .035), and coarse chromatin ( P = .009). SurePath achieved greater cellularity than ThinPrep, with 18.6% and 0% of cases, respectively, showing very high cellularity ( P < .001).

For EUS-guided FNB of solid pancreatic masses, the SurePath LBC technique demonstrated superior diagnostic performance, faster interpretation times, and better preservation of cytomorphologic features than ThinPrep. These findings suggest that SurePath should be the preferred LBC method for evaluating EUS-guided FNB of pancreatic masses. (Clinical trial registration number: KCT0006748).