Background Suspected malignant biliary strictures lacking a confirmed tissue diagnosis pose a diagnostic dilemma, putting patients at risk of undergoing major surgery for a potentially benign disease process or repeated diagnostic procedures. Although highly specific, the disappointingly low sensitivity of biliary brush cytology has prompted development of newer equipment and techniques.

Aim We aimed to determine if using a new, larger-bristled “Infinity” brush (US Endoscopy) led to superior detection of malignant biliary strictures at cytology than the “RX” brush (Boston Scientific).

Method We retrospectively reviewed the case notes of 58 patients who had undergone ERCP and brushings within Mater Hospital, Belfast between May 2011–2016. Of these, 33 had been diagnosed with histopathologically-confirmed pancreaticobiliary cancers. The RX brush was used in 13 cases; the Infinity brush in 20 cases.

Results Cytology from the 13 patients with RX brush yielded 5 with cells confirming adenocarcinoma. Of 20 patients whose strictures had been brushed with an Infinity brush, 11 had adenocarcinoma identified. Assuming atypical cells to be classified as non-malignant, the RX brush achieved a sensitivity of 38.5%, in comparison to the 55% sensitivity of the Infinity Brush.

Conclusions The use of the Infinity cytology brush provided a higher yield in detection of malignant cells in our patients than the Boston RX cytology brush, possibly due to its size, design and bristle configuration. We acknowledge however our study numbers were small and we feel that a larger study would be required to determine if the difference in brushings yield is significant.