Unplanned but proven obsolescence for 19 G endoscopic ultrasound needles

Who would have bet on a long life for 19 G needles used for endoscopic ultrasound (EUS)-guided fine-needle aspiration (FNA)? These large-bore needles have never been popular among endosonographers, mainly due to their stiffness and known technical failures, especially when used transduodenally. Until recently, however, they were still considered essential in diseases for which a core specimen and histology was mandatory for diagnosis.

“RCTs, even in a rapidly growing specialty such as digestive endoscopy, still deserve recognition and publication as solid evidence for future guidelines, as demonstrated by the Laquière et al. RCT published in this issue.”

Recent European Society of Gastrointestinal Endoscopy (ESGE) guidelines suggest to use 19 G FNA or fine-needle biopsy (FNB) needles or 22 G FNB needles when the primary aim of sampling is to obtain core tissue (low quality evidence, weak recommendation) [1]. These indications include well-differentiated adenocarcinomas, autoimmune pancreatitis, and sarcoidosis. Tissue specimens also allow for additional immunohistological evaluation, which is essential in the diagnosis of diseases such as lymphoma, neuroendocrine neoplasms, and gastrointestinal (GI) stromal tumors [2]. Moreover, providing histological samples that yield an adequate amount of tumor cells and desmoplastic stroma suitable for molecular analysis is becoming essential for personalized oncological treatment [3].

Therefore, improvements in 19 G needles to decrease technical failure and improve specimen collection were awaited. The first modification called “reverse bevel” was a modified 19 G Menghini-type needle with a beveled side slot near the needle tip. The slot cutting edge directs backward to collect tissue during retrograde movement of the needle. This modification, however, did not improve the stiffness (on the contrary), and the concept was redeveloped in 20-, 22-, and 25 G needles rather than being pursued in 19 G needles. A new 19 G FNA needle made from nitinol was shown to offer mechanical performance advantages in benchtop testing [4], but clinical evidence was limited, and no comparative data were available [5].

In this issue of Endoscopy, Laquière et al. report on a multicenter (18 expert centers and 21 investigators), randomized, prospective study promoted by the French Society of Digestive Endoscopy, and conducted from September 2013 to August 2016 [6]. The authors randomized 125 patients with pancreatic head masses and compared standard 22 G needles with 19 G nitinol needles for transduodenal EUS-guided FNB. Despite improved flexibility, the 19 G nitinol needle was still associated with a higher failure rate and lower diagnostic accuracy, although the quality of the specimen obtained was not different between the needles.

This randomized controlled trial (RCT) is a perfect example of a well-designed trial that will be cited in most guidelines, as it is original and undisputable; however, it comes too late in a fast-growing area of medicine. GI endoscopy is indeed considered to be one of the most rapidly moving technical specialties, with new devices and techniques in constant evolution and improvement. Designing prospective randomized trials is therefore challenging, especially when one has to choose a specific new device and its “control” opponent. EUS is not left out of these changes, with the rapid expansion of therapeutic indications (e. g. collection and ductal drainage, gallbladder drainage, gastrojejunal anastomosis, gastro-gastroplasties, pancreatic ablation with radiofrequency ablation), and the changing need and trend in diagnosis from cytology to histology and its ancillary techniques.

The debate between defenders of on-site cytological diagnosis with FNA needles and proponents of systematic collection of core and histology specimens is now almost over. This is not only due to the oncological demand but also to the development of new 22 G FNB needles that appear to reliably yield true histology samples. These new needles are designed with a reverse bevel system (ProCore needles; Cook Medical, Bloomington, Indiana, USA), a fork-shaped needle with two sharp tips (SharkCore; Medtronic, Minneapolis, Minnesota, USA), or a crown-shaped needle (Franseen type) with three sharp tips (Acquire; Boston Scientific Corp., Marlborough, Massachusetts, USA). These features allow the fibrotic components to be grasped and cut between the tips. But of course, these new thinner FNB needles have been the death knell for the 19 G needles since 2016 – interestingly, the year in which the Laquière et al. trial was completed.

Recent randomized trials with these new FNB needles showed that the diagnostic yield on cell block exceeded 95 % and that the specimen could serve for both immunohistochemistry and molecular profiling [7]. These findings are in line with a recent report that included nearly 1000 patients who underwent EUS-FNB. Bang et al. demonstrated that from the year 2016, when FNB needles were used for EUS-guided tissue acquisition of solid mass lesions, the diagnostic adequacy on cell block increased to more than 90 % and a median of just one pass was sufficient to achieve on-site diagnostic adequacy in more than 95 % of patients [8].

It seems, therefore, that designing RCTs on new devices, and especially on new needles or instruments with a rapid evolution, may be challenging if not disappointing. At the time of publication, these RCTs may indeed already be outdated by newer devices or techniques that were developed in the meantime. Should we still aim to design these trials? Of course, we should! RCTs, even in a rapidly growing specialty such as digestive endoscopy, still deserve recognition and publication as solid evidence for future guidelines, as demonstrated by the Laquière et al. RCT published in this issue. The lack of solid RCTs is one of the reasons why most recommendations in recent endoscopy guidelines based on retrospective or noncontrolled prospective studies, are of a moderate or even low quality level (four levels of evidence quality according to Grading of Recommendations Assessment, Development and Evaluation guidelines). Such RCTs should, however, be planned, executed, and published as quickly as possible, before new techniques or devices render them obsolete. The current case illustrates the unplanned but now proven obsolescence of the diagnostic 19 G needles.

• References

• 1 Polkowski M, Jenssen C, Kaye P. et al. Technical aspects of endoscopic ultrasound (EUS)-guided sampling in gastroenterology: European Society of Gastrointestinal Endoscopy (ESGE) Technical Guideline. Endoscopy 2017; 49: 989-1006
• 2 Ishiwata T, Yasuda I, Shimizu M. Endoscopic ultrasound-guided tissue acquisition: can fork and crown cut the tissue?. Dig Endosc 2018;
• 3 Deprez PH. Future directions in EUS-guided tissue acquisition. Gastrointest Endosc Clin N Am 2014; 24: 143-149
• 4 Itoi T, Itokawa F, Sofuni A. et al. Evaluation of 19-gauge endoscopic ultrasonography aspiration needles using various echoendoscopes. Endosc Int Open 2013; 1: 24-30
• 5 Varadarajulu S, Bang JY, Hebert-Magee S. Assessment of the technical performance of the flexible 19-gauge EUS-FNA needle. Gastrointest Endosc 2012; 76: 336-343
• 6 Laquière A, Lefort C, Maire F. et al. 19 G nitinol needle versus 22 G needle for transduodenal endoscopic ultrasound-guided sampling of pancreatic solid masses: a randomized study. Endoscopy 2019; 51: 436-443
• 7 Bang JY, Hebert-Magee S, Navaneethan U. et al. Randomized trial comparing the Franseen and Fork-tip needles for EUS-guided fine needle biopsy sampling of solid pancreatic mass lesions. Gastrointest Endosc 2018; 87: 1432-1438
• 8 Bang JY, Kirtane S, Krall K. et al. In memoriam: fine-needle aspiration, birth: fine-needle biopsy: the changing trend in endoscopic ultrasound-guided tissue acquisition. Dig Endosc 2018;