Reply to Ustundag et al.

In the comment on our recent paper [1] describing the technical results and complications of fine needle aspiration (FNA) of pancreatic cysts, Ustundag et al. highlight several important issues pertaining to the role of endoscopy-guided FNA in the diagnostic work-up of pancreatic cysts.

Our paper focused on the diagnostic value and safety of FNA in the evaluation of a consecutive series of patients with pancreatic cysts. FNA contributed in only a limited number of cases but had a low complication rate. We did not specifically correlate the cyst characteristics with the success rate of FNA because this was not a specific goal of the study and the numbers were probably too small to make meaningful conclusions. In our study we attempted to perform endoscopic ultrasound (EUS)-guided FNA of every pancreatic cyst (except for those where it was felt to be inappropriate for the reasons mentioned in the paper), regardless of its size or other characteristics. In doing so, we collected a large cohort of patients with different cyst types that reflected daily practice.

We agree with Ustundag et al. that the use of a 19-gauge rather than 22-gauge needle may indeed be more suitable when puncturing larger cysts or those that contain fluid with a high viscosity, as we suggest in the discussion of our paper. However, to our knowledge no literature exists to support this hypothesis. In the current protocol we did not routinely attempt to puncture the wall of each pancreatic cyst as in our opinion evidence for this strategy is lacking. The study that Ustundag et al. mention in their letter is retrospective and limited to mucinous cysts; furthermore, surgical specimens as a reference standard were available in approximately 20 % of cases only, making it difficult to compare cyst wall puncture with routine aspiration using FNA [2].

In our study onsite pathology was never available. Because we tried to aspirate as much fluid as possible, we chose to first spin down the fluid to collect as many cells as possible. Recently two studies have been published that describe a new type of brush (EchoBrush; Cook) [3] [4]. We believe this technique is promising but larger series are necessary to definitively introduce this procedure into daily practice. As Dr. Ustundag and colleagues remark, new techniques such as molecular analysis and proteomics may be helpful in the future for the differential diagnosis of pancreatic cysts. In conclusion, in our study the value of FNA in the diagnostic approach for pancreatic cysts was limited and new techniques to improve the differential diagnosis of pancreatic cysts are needed.

References

• 1 de Jong K, Poley J W, van Hooft J E et al. Endoscopic ultrasound-guided fine-needle aspiration of pancreatic cystic lesions provides inadequate material for cytology and laboratory analysis: initial results from a prospective study.  Endoscopy. 2011;  43 585-590
• 2 Rogart J N, Loren D E, Singu B S, Kowalski T E. Cyst wall puncture and aspiration during EUS-guided fine needle aspiration may increase the diagnostic yield of mucinous cysts of the pancreas.  J Clin Gastroenterol. 2011;  45 164-169
• 3 Al-Haddad M, Raimondo M, Woodward T et al. Safety and efficacy of cytology brushings versus standard FNA in evaluating cystic lesions of the pancreas: a pilot study.  Gastrointest Endosc. 2007;  65 894-898
• 4 Bruno M, Bosco M, Carucci P et al. Preliminary experience with a new cytology brush in EUS-guided FNA.  Gastrointest Endosc. 2009;  70 1220-1224