Could pre-operative NE-NBI finding be useful to determine accurate surgical margins in undifferentiated-type early gastric cancer patients?

Early gastric cancer (EGC) is defined as being mucosal or submucosal invasion, and is curative because of the low risk of lymphovascular metastasis (1). In the 2000s, endoscopic submucosal dissection (ESD) was developed and prevailed for the curative resection of EGC (2,3), and the diagnostic modalities have also been improved, including high-resolution white light imaging (WLI) (4), narrow band imaging (NBI) (5), and catheter probe endoscopic ultrasound (EUS) (6). Of note, the usefulness of magnifying endoscopy with NBI (ME-NBI) has been recognized as indispensable and widely used in daily ESD, or for the preoperative determination of the surgical margin in Japan.

On the other hand, due to the lower comparative prevalence of gastric cancer in the West, there is less usage of NBI in daily practice during diagnostic gastroscopy. In addition, with the lack of combined ME-NBI facilities in many European district general hospitals at present, much experience and training are still required in ME-NBI to help improve the detection of EGC.

With ME-NBI, Yao et al. established a VS classification system with high-level accuracy (4), focusing microvascular (MV) pattern and microsurface (MS) pattern. Nowadays, many endoscopists are combining both WLI and ME-NBI as reliable diagnostic tools for EGC (7). Probe-type EUS has been used and could provide more information on the depth of invasion, which could not be assessed correctly by WLI or ME-NBI because these modalities are mainly used for diagnosis of the differentiation type and demarcation line only from the surface pattern of the tumor. Therefore, if it is difficult to determine the depth with WLI, then probe-type EUS could give additional, beneficial information about the depth of the EGC (8), and sometimes it is indispensable before ESD.

In spite of recent advances for an accurate endoscopic diagnosis, an accurate preoperative diagnosis of undifferentiated (UD)-type EGC is still difficult. Nakayoshi et al. reported a UD-type EGC with ME-NBI is characterized by the irregular vessels with a “corkscrew sign” (9). In issue of Annals of Laparoscopic and Endoscopic Surgery, a study is presented by Horiuchi et al. on the usefulness of ME-NBI for the preoperative determination of UD-type EGCs (10). The authors reported that on using WLI only, 47.3% of cases had a preoperatively diagnosed tumor margin in UD-type EGCs, and with combined WLI and ME-NBI, the accurate diagnosis rate improved to 81.5%. A more improved modality is needed because of nearly 20% cases still could not receive a margin diagnosis, however, considering the inapplicability of data using WLI only, ME-NBI is indispensable as a preoperative modality to perform curative gastrectomy. Their results support previous studies and suggest a more informed decision on the safe surgical margin is needed for UD-type EGC.

Acknowledgments

Funding: None.

Footnote

Provenance and Peer Review: This article was commissioned by the editorial office, Annals of Laparoscopic and Endoscopic Surgery. The article did not undergo external peer review.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at http://dx.doi.org/10.21037/ales.2017.01.01). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Gotoda T, Yanagisawa A, Sasako M, et al. Incidence of lymph node metastasis from early gastric cancer: estimation with a large number of cases at two large centers. Gastric Cancer 2000;3:219-25. [Crossref] [PubMed]
2. Yamamoto H, Sekine Y, Higashizawa T, et al. Successful en bloc resection of a large superficial gastric cancer by using sodium hyaluronate and electrocautery incision forceps. Gastrointest Endosc 2001;54:629-32. [Crossref] [PubMed]
3. Ono H, Kondo H, Gotoda T, et al. Endoscopic mucosal resection for treatment of early gastric cancer. Gut 2001;48:225-9. [Crossref] [PubMed]
4. Yao K, Anagnostopoulos GK, Ragunath K. Magnifying endoscopy for diagnosing and delineating early gastric cancer. Endoscopy 2009;41:462-7. [Crossref] [PubMed]
5. Ezoe Y, Muto M, Uedo N, et al. Magnifying narrowband imaging is more accurate than conventional white-light imaging in diagnosis of gastric mucosal cancer. Gastroenterology 2011;141:2017-2025.e3. [Crossref] [PubMed]
6. Ichikawa T, Kudo M, Matsui S, et al. Endoscopic ultrasonography with three miniature probes of different frequency is an accurate diagnostic tool for endoscopic submucosal dissection. Hepatogastroenterology 2007;54:325-8. [PubMed]
7. Yamada S, Doyama H, Yao K, et al. An efficient diagnostic strategy for small, depressed early gastric cancer with magnifying narrow-band imaging: a post-hoc analysis of a prospective randomized controlled trial. Gastrointest Endosc 2014;79:55-63. [Crossref] [PubMed]
8. Yamamoto S, Nishida T, Kato M, et al. Evaluation of endoscopic ultrasound image quality is necessary in endosonographic assessment of early gastric cancer invasion depth. Gastroenterol Res Pract 2012;2012:194530.
9. Nakayoshi T, Tajiri H, Matsuda K, et al. Magnifying endoscopy combined with narrow band imaging system for early gastric cancer: correlation of vascular pattern with histopathology (including video). Endoscopy 2004;36:1080-4. [Crossref] [PubMed]
10. Horiuchi Y, Fujisaki J, Yamamoto N, et al. Accuracy of diagnostic demarcation of undifferentiated-type early gastric cancer for magnifying endoscopy with narrow-band imaging: surgical cases. Surg Endosc 2016; [Epub ahead of print]. [Crossref] [PubMed]