Reply to Bronswijk

We would like to thank our highly esteemed colleague, Michiel Bronswijk, for his interest in our article and especially for this opportunity to discuss such an important subject.

First, our statement about the safety and efficacy of the fine needle injection of alcohol is obviously not based on our single case outcome. The opinion that the procedure is safe and effective for treating small pancreatic lesions in patients who are in poor general condition or who refuse surgery is reported in studies [1] [2] [3] [4] [5], including the one by Park et al. [5], cited by Bronswijk as “the largest follow-up of [pancreatic neuroendocrine tumors] pNETs treated with [endoscopic ultrasound] EUS-guided alcohol ablation.”

In addition, all the studies that we have read on the topic, including those cited in the comments by Bronswijk, present several limitations. These include: low number of patients enrolled (the major and most frequent problem); absence of homogeneity of patient selection; poor protocols for inclusion and exclusion criteria; short follow-up period; and absence of technical standardization for performance of the ablation. Such limitations underlie the current difficulty in establishing the “gold standard” procedure. Even though some articles have shown higher efficacy rates with radiofrequency ablation (RFA), the results are not sufficient to condemn alcohol ablation.

We now address some issues regarding specific references cited in the comments. It was said that the 2017 trial [6] revealed a significant reduction in adverse events when alcohol was omitted from the ablation protocol, with no statistically significant difference in efficacy. It is worth remembering that this alcohol-free protocol contained a specific chemotherapeutic cocktail, targeted to treat mucinous pancreatic cysts, which was the study’s objective in the first place. Therefore, we cannot infer that the same efficacy will be achieved when treating nonmucinous lesions with the same protocol.

Regarding the 2016 study, which followed up 91 patients after EUS-guided fine needle injection of ethanol into pancreatic cystic lesions [5], contrary to what was stated in the comments, none of the lesions treated were confirmed pNETs. This also takes us back to the lack of homogeneity of the samples when we analyze articles on this topic.

We agree that RFA seems to be a safer and more efficient procedure, as suggested by the 2019 prospective, multicenter study [7]. Nevertheless, as the authors of the study concluded, even after achieving an 86 % rate of complete remission and 10 % rate of severe complications, “further studies with more patients and a longer follow-up are required.”

Alcohol ablation requires much smaller financial resources than RFA. We are working in a public hospital in a developing country, and the technique allows us to provide appropriate evidence-based care for more patients in such difficult conditions.

• References

• 1 Lakhtakia S. Therapy of pancreatic neuroendocrine tumors: fine needle intervention including ethanol and radiofrequency ablation. Clin Endosc 2017; 50: 546-551
• 2 Park DH, Choi JH, Oh D. et al. Endoscopic ultrasonography-guided ethanol ablation for small pancreatic neuroendocrine tumors: Results of a pilot study. Clin Endosc 2015; 48: 158-164
• 3 Qin SY, Lu XP, Jiang HX. EUS-guided ethanol ablation of insulinomas: Case series and literature review. Medicine (Baltimore) 2014; 93: e85
• 4 Levy MJ, Thompson GB, Topazian MD. et al. US-guided ethanol ablation of insulinomas: a new treatment option. Gastrointest Endosc 2012; 75: 200-206
• 5 Park JK, Song BJ, Ryu JK. et al. Clinical outcomes of endoscopic ultrasonography-guided pancreatic cyst ablation. Pancreas 2016; 45: 889-894
• 6 Moyer MT, Sharzehi S, Mathew A. et al. The safety and efficacy of an alcohol-free pancreatic cyst ablation protocol. Gastroenterology 2017; 153: 1295-1303
• 7 Barthet M, Giovannini M, Lesavre N. et al. Endoscopic ultrasound-guided radiofrequency ablation for pancreatic neuroendocrine tumors and pancreatic cystic neoplasms: a prospective multicenter study. Endoscopy 2019; DOI: 10.1055/a-0824-7067. [Epub ahead of print]