Gastric adenomas are benign lesions that arise from the inner lining of the stomach. If left untreated, gastric adenomas can progress into gastric cancer, emphasizing the importance of early detection and treatment of such adenomas. Endoscopic resection is widely used to treat superficial gastric neoplastic lesions. Current guidelines recommend endoscopic resection for the treatment of gastric superficial neoplastic lesions, such as gastric adenomas or early gastric cancers (EGCs) [1-4]. While endoscopic submucosal dissection (ESD) is the recommended treatment of choice for gastric superficial neoplastic lesions [4,5], endoscopic mucosal resection (EMR) is preferred for lesions smaller than 10–15 mm that are not likely to show advanced histological findings. Modified EMR procedures facilitate the safe and rapid removal of small gastric lesions; these procedures include EMR after circumferential precutting (EMR-P), cap-assisted EMR (EMR-C), and EMR using a ligation device (EMR-L). For low-grade dysplasia, argon plasma coagulation (APC) can be used to remove lesions faster, more conveniently, and with fewer complications compared to mucosal or submucosal dissection [6].

EMR-P is the preferred treatment approach for gastric adenomas. In EMR-P, adenoma removal involves the creation of a circular incision around the adenoma, followed by lifting and resection of the lesion. Contrastingly, in ESD, en bloc resection of the lesion is performed by dissecting and removing the submucosal layer. Both EMR-P and ESD have proven to be effective for treating gastric neoplastic lesions [7,8]. However, the debate regarding the most effective technique for adenomas, especially those with a diameter of ≤15 mm, is still ongoing. This cutoff diameter is important because it represents a clinically relevant size threshold for the management of gastric adenomas. Selecting between EMR-P and ESD for small gastric adenoma treatment is challenging, as it necessitates the identification of the technique yielding superior outcomes in terms of complete resection, safety, and recurrence rate. Understanding the advantages and disadvantages of each technique would facilitate selection of the optimal treatment approach for each patient. While previous studies have compared EMR-P and ESD for EGC [7], no consensus has been reached on the optimal treatment approach for smaller gastric adenomas. A comprehensive evaluation of the treatment of adenomas ≤15 mm is required to guide clinical decision-making. Thus, this study aimed to compare the outcomes of EMR-P and ESD for gastric adenomas ≤15 mm in size.

Gastric adenomas are precancerous lesions. Appropriate diagnosis and treatment of these lesions are crucial for the early detection and prevention of gastric cancer. While consensus regarding the treatment of HGDs has been achieved, the treatment of LGDs remains controversial. LGDs have a low probability of progressing to cancer (<10%), and some spontaneously disappear during follow-up [9,10]. Therefore, a previous version of the revised Vienna classification [11] recommended endoscopic treatment or follow-up for LGDs and endoscopic treatment for HGDs. However, the most recent guidelines recommend endoscopic treatment for HGDs and endoscopic resection for accurate pathological diagnosis for most LGDs. The most recent British Society of Gastroenterology (BSG) guidelines recommend complete endoscopic resection of both LGDs and HGDs [3]. Furthermore, the American Society for Gastrointestinal Endoscopy guidelines also recommend endoscopic resection of adenomas of any grade or size [2].

Considering the histologic discrepancy between forceps biopsy and endoscopic resection, ESD is an effective treatment approach for HGDs or lesions that are highly likely to progress to cancer after endoscopic resection. Risk factors that indicate a high risk of high-grade dysplasia or malignancy development are a lesion size of >2 cm and the presence of a depression, a rough or reddish surface, and spontaneous bleeding. Although several previous studies have reported that ESD is more effective than EMR for endoscopic resection of superficial gastric neoplastic lesions [7,12-14], ESD is associated with a high frequency of complications, such as bleeding and perforation. It requires more time and is costlier than EMR. In Korea, the cost of an ESD knife is approximately 210000 KRW (158 USD), and additional costs are incurred if additional knives are used. In EMR-P, the cost of the snare is approximately 64000 KRW (48 USD), which is the same as that of conventional EMR because the snare tip is used for precutting. Socioeconomically, differences in the scope of medical expense coverage based on the medical insurance system of each country may affect the choice of treatment method. Another limitation of ESD is that the success of the procedure depends on operator proficiency.

EMR is a widely used treatment method because it requires less time than ESD and is relatively less affected by the operator’s skill level. EMR is an acceptable option for LGDs smaller than 10–15 mm that are not associated with risk factors. Modified EMR technique, including EMR-P, EMR-C, and EMR-L, were developed to safely and rapidly remove small gastric lesions. However, compared with ESD, EMR has a lower rate of en bloc and complete resection. In particular, en bloc and complete resection rates decrease significantly when the lesion is >2 cm in size or has an unfavorable location. Therefore, EMR may be a good method for treating small LGDs with no associated risk factors. Nevertheless, no clear cutoff for lesion size is currently available to determine treatment methods. The BSG guidelines recommend EMR for gastric adenomas ≤10 mm in size and EGC and ESD for lesions >10 mm in size. Japanese studies have reported that en bloc resection rates are significantly lower with EMR than with ESD for tumors >1 cm in size [15-17]. In Korea, ESD for LGDs <15 mm without fibrosis is not covered by medical care and EMR or APC are widely used to treat such lesions in clinical practice. Compared with endoscopic resection, APC offers advantages such as shorter operative time, lower risk of bleeding or perforation, no requirement for hospitalization, lower operative cost, and reduced reliance on operator skill. However, APC for large or sunken lesions is associated with a low treatment efficacy and high recurrence rate. In addition, a biopsy of the entire lesion cannot be performed. Therefore, EMR is preferred for small LGDs, with EMR-P recommended as a good approach in such cases.

Although previous studies have compared the effectiveness of ESD and modified EMR for EGC resection [7], few studies have analyzed the effects of ESD and modified EMR on small gastric adenomas. Our study provides important insights by comparing the effectiveness of EMR-P and ESD for gastric adenomas ≤15 mm. Our findings indicate that ESD is more effective than EMR-P in achieving complete resection of smaller adenomas, which is consistent with the results of previous studies, which demonstrated the superiority of ESD for larger lesions. As ESD facilitates accurate dissection and removal of the submucosal layer, thereby ensuring the complete removal of the lesion, it leads to higher complete and en bloc resection rates. In contrast, EMR-P involves lesion resection without dissection of the submucosal layer, potentially increasing the risk of incomplete resection and residual adenoma tissue. However, the longer procedure times associated with ESD requires consideration, as this may increase patient discomfort and potentially limit the applicability of this technique. Thus, endoscopists should consider the trade-off between effectiveness and efficiency when choosing the appropriate resection technique. Notably, our findings indicate that both EMR-P and ESD are safe in terms of perforation and bleeding rates, suggesting that both techniques can be performed safely with the appropriate expertise and caution. Endoscopists should carefully consider their own experience and skills when deciding which technique to use.

In the present study, while the histological complete resection rate differed significantly between the two groups, the local recurrence rate did not. This may be due to the securing additional margins by tissue ablation during the pre-cut process and the interpretation of false-positive tumor margins in the pathology results owing to the effects of cautery during the procedure. The similar recurrence rates between the two groups indicate that both techniques are effective in preventing the recurrence of gastric adenomas ≤15 mm. However, long-term follow-up studies are required to evaluate the durability of resection and assess the long-term risk of recurrence.

Furthermore, herein, the tumor size was significantly smaller in the EMR-P group than in the ESD group (6.9 mm vs. 8.5 mm, p<0.05). This difference is thought to be because EMR-P was preferred for the resection of slightly smaller adenomas, as the procedure was chosen per the operator’s discretion. As the complete resection rate in ESD is higher than that in EMR for small adenomas, ESD may be the most effective resection method. Our study demonstrated that a non-antral tumor location was significantly associated with incomplete histological resection. Thus, herein, consistent with the results of previous studies [18,19], the lesion location was an important factor that affected curative endoscopic resection.

This study has several limitations that require consideration. First, because the procedures were performed at a single hospital, the sample size was relatively small, which may limit the generalizability of our findings. Second, the basic characteristics of the EMR-P and ESD groups differed because this was a retrospective rather than a randomized study. There were more patients in the ESD group than in the EMR-P group. In addition, the tumor size was significantly smaller and the proportion of HGDs was lower in the EMR-P group. Finally, the follow-up period was relatively short, with five patients having a follow-up period of <3 months and 42 patients having a follow-up period of <6 months. This may have affected our analysis of recurrence rates. Therefore, it would be beneficial to report the long-term results of these data in a follow-up study.

In conclusion, our study suggests that in terms of complete resection, ESD is more effective than EMR-P for gastric adenomas ≤15 mm in size. However, ESD is a challenging procedure in terms of skill, and it involves a long operative time and high cost. For gastric adenomas ≤15 mm, EMR-P may be preferred considering the en bloc resection rate, procedure time, and local recurrence rate. Nevertheless, considering the complete resection rate, ESD is recommended as the treatment of choice for HGDs and EGC. The choice between the two techniques should be based on individual patient factors and operator expertise. Further studies are required to validate our findings and evaluate long-term outcomes.