麻豆传媒

Endoscopic submucosal dissection (ESD) appeared effective for removing superficial gastric neoplasia and is therefore a viable option for patients in North America, a retrospective, multicenter study found.

A common technique in Asian countries, ESD is associated with low risk of local recurrence, but careful endoscopic surveillance remains necessary to identify metachronous lesions. But, thus far, data on ESD outcomes on this continent have been few and largely from small single-center studies, the authors noted.

Now, Saowanee Ngamruengphong, MD, of Johns Hopkins Hospital in Baltimore, and colleagues have published outcomes in 347 patients from 25 North American centers who underwent ESD for superficial gastric neoplasia.

In a manuscript published online in the group reported that 92.2% had en-bloc resection and 81.8% received curative R0 resection across all lesions. About 7% experienced perforations during the procedure; 82% of these were successfully managed with endoscopic treatment.

Local recurrence (3.9%) was observed only after non-curative resection. Metachronous lesions were identified in 14 patients (6.9%). One of 277 patients with clinical follow-up died of metachronous gastric cancer occurring 2.5 years after the initial ESD.

Delayed bleeding occurred in just under 3%, and no patients had delayed perforation or died as a result of ESD. Surgery was required for ESD-related adverse events in 1.1% of cases.

The patient population was 56% male and 46% Caucasian, with an overall mean age of 69 (+12). The median interval between initial ESD and last clinical or endoscopic evaluation was 364 days. Diagnoses prior to ESD were as follows:

• 90 adenomas or low-grade dysplasias
• 82 high-grade dysplasias
• 139 early gastric cancers
• 36 neuroendocrine tumors

Co-author Amit Bhatt, MD, of the Cleveland Clinic, told 麻豆传媒 that while gastric cancer is one of the most common cancer types in Asia and significant efforts have been made to detect and treat it early, it is the 14th most common cancer in the U.S. and is mostly diagnosed in the later stages.

"Endoscopic submucosal dissection was developed in Japan to allow for organ sparing endoscopic resection of early gastric cancer with high curative resection rates and quickly became the standard of care for early gastric cancer in many Asian countries," he said.

Though difficult to master, the technique will likely become more available in this country.

"Although ESD is a highly specialized procedure and technically demanding, it has increasingly gained popularity in the United States," Ngamruengphong told 麻豆传媒. "An increasing number of endoscopists are acquiring training in ESD, and the national professional societies have offered ESD training so U.S. physicians don't have to travel to Japan to learn it."

The more common technique of involves submucosal injection and/or suction and subsequent snare resection of lesions, the authors explained, but EMR often results in piecemeal resection. ESD overcomes these limitations, allowing en-bloc resection of superficial neoplasia regardless of size and minimizing local recurrence. It also facilitates precise histological assessment of the resected specimen and improves curative resection.

"There are more patients in the United States that could benefit from ESD that are likely undergoing surgical resection," Sunguk Jang, MD, also of the Cleveland Clinic, who was not involved with the research, told 麻豆传媒. "Hopefully this study can help spread awareness of the organ sparing benefits of gastric ESD."

Compared with EMR, a of nonrandomized studies found ESD yielded a higher en-bloc resection rate (92% vs 52%), higher histologically complete resection rate (82% vs 42%), and lower local recurrence rate (1% vs 6%), even for lesions smaller than 10 mm. In light of these results, the recommend this technique as the treatment of choice for most superficial gastric neoplasia, while reserving EMR for lesions smaller than 10-15 mm with a very low probability of advanced histology.

And comparing their North American ESD results with those from Eastern countries, Ngamruengphong's group noted that in an earlier meta-analysis involving 59,173 gastric lesions, both en-bloc resection and R0 resection rates were slightly higher in the latter countries, at 94% and 91%, respectively. Their lower resection success rates may be explained, they said, by the lower incidence of gastric neoplasia in North America versus Asia, and the fact that ESD is not yet widely available here since it is time-consuming and involves a steep learning curve.

The current study's limitations included its retrospective design and lack of long-term follow-up data, the authors said. Lastly, almost half of the patients in this study had severe systemic disease, which could indicate selection bias toward endoscopic resection rather than surgery and may not allow for long-term follow-up for oncologic outcomes.

"ESD is technically challenging to perform with a flat (difficult) learning curve," Bhatt said. "Not only do significant efforts need to be made to learn the procedure, but procedures need to be performed regularly to gain and maintain competency, and overall case volumes are currently low in the United States."

In addition, Bhatt noted a number of nonclinical barriers to implementing ESD in the U.S. -- for example, there are no dedicated billing codes, so appropriate reimbursement can be challenging.

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