Gastric polyps are not created equal: Know your enemy

Abstract

Gastric polyps are commonly detected during upper gastrointestinal endoscopy. They are most often benign and rarely become malignant. Nevertheless, adequate knowledge, diagnostic modalities, and management strategies should be the endoscopist’s readily available “weapons” to defeat the potentially malignant “enemies”. This article sheds light on the valuable effort by Costa et al to generate a new classification system of gastric polyps as “good”, “bad”, and “ugly”. This comprehensive overview provides clinicians with a simplified decision-making process.

Key Words: Gastric polyps; Polypoid subepithelial lesions; Early gastric cancer; Endoscopic ultrasonography; Electronic chromoendoscopy

Core Tip: Knowing and understanding the risks associated with gastric polyps (GPs) is an important step in diagnosing and managing them. Knowing “when to do”, “what to do”, and “how to do” is important for not missing any significant pre-malignant GPs. A good classification reinforces the clinical prerequisites for endoscopists when dealing with GPs during upper gastrointestinal endoscopy.

TO THE EDITOR

Gastric polyps (GPs) are frequently detected during upper endoscopy to investigate dyspepsia and acid-related disorders. Fundic GPs are the most frequently identified subtype, and their formation is linked to the wide use of proton pump inhibitors[1]. “If you know the enemy and know yourself, you need not fear the result of a hundred battles”, this famous quote by Sun Tzu applies to GP management.

CHOOSING YOUR WEAPON

The term subepithelial lesion (SEL) is preferred over submucosal tumor to describe GPs, as the term submucosal tumor specifically describes lesions emerging from the submucosal layer[2]. Polypoid SELs in the stomach can arise from the muscularis mucosa, submucosa, or muscularis propria. To accurately evaluate these lesions, the initial step is histologic assessment through sampling biopsies or complete resection. However, standard endoscopic forceps biopsy of the mucosa overlying SELs often fails to obtain sufficient tumor tissue for pathology. Therefore, specialized techniques like bite-on-bite, jumbo, and snare biopsy have been developed. In addition, newer techniques, such as unroofing the SEL to expose its surface or the creation of a submucosal tunnel, allow for direct tumor biopsy. Third-space endoscopy techniques that rely on submucosal dissection have improved the quality of endoscopic sampling and facilitated the pathologist’s task by providing better tissue specimens[3]. The European Society of Gastrointestinal Endoscopy recommends endoscopic ultrasonography (EUS) to characterize SEL features (size, location, originating layer, echogenicity, shape). For diagnosis of SELs measuring 20 mm or larger, EUS-guided fine-needle biopsy and mucosal incision-assisted biopsy are equally recommended[4,5]. Both techniques have been compared in three randomized controlled trials, and there were no significant differences found for complication rate or the diagnostic samples. Mucosal incision-assisted biopsy is more time-consuming and might make subsequent SEL resection more challenging via submucosal endoscopic tunneling. However, the European Society of Gastrointestinal Endoscopy recommends it as the first choice for SELs ≤ 20 mm, even though there is little supporting evidence[6-8].

KNOWING YOURSELF WELL

Diagnosis of GPs requires proper endoscopic characterization using Paris classification[9] and dye-based or electronic chromoendoscopy[10]. The presence of features suggestive of mucosal invasion in GP cases is a pivotal factor that warrants complementary EUS to determine invasion depth before considering endoscopic resection of a suspicious-looking GP. Once the pathology report is received, determining the need for surveillance and follow-up endoscopy timing is the next step. Guidelines addressing these issues are scarce in the medical literature[10]. In this issue, Costa et al[11] propose a simple but very practical classification system for GPs based on pathological type: The good, the bad, and the ugly. The authors are to be congratulated for their thoroughness in reviewing published evidence and detailing the best management for each GP. However, the classification relies primarily on polyp morphology and malignant potential evaluation to decide between resection or surveillance. Although advanced endoscopic resection techniques are becoming widespread in gastroenterological practice, they are associated with increased risks of complications compared to simple excisional biopsies. Thus, the only caveat of the proposed classification is the potential overuse of more invasive and riskier sampling techniques to ensure the most reliable sample for pathologic examination[12]. On the other hand, endoscopic surveillance impacts long-term healthcare expenditures, and a “watchful waiting” scenario of good/bad GPs might be associated with higher patient anxiety levels.

KNOWING YOUR BATTLEFIELD

Evaluation of the surrounding mucosa for atrophy, intestinal metaplasia, and dysplasia is essential and could result in a good GP being classified as “bad” and warrant earlier surveillance. This concept is well emphasized in the review. Finally, not all GPs or SELs are pathogenic. EUS features of SELs are pathognomonic for lipoma and varices. Fundic GPs are originally “good” in most cases, and syndromic ones are rarely encountered.

CONCLUSION

GPs can be complicated and difficult to classify or diagnose. A major difference exists between “good”, “bad”, and “ugly” GPs, though endoscopists should be aware of how to deal with each type. A good evaluation is possible with the foundation of good knowledge, and an adequate classification system would be effective in facilitating this. Such a model builds the cornerstone of future guidelines concerning the management of GPs. Future research should focus on comparing new endoscopic sampling techniques and their relative contribution to refining GP characterization. Long-term follow-up studies of “good” and “bad” GPs with a low to intermediate neoplastic transformation potential are warranted to define endoscopic surveillance intervals.