Review for 10.1186/s12876-023-03107-5 (2024)

Title: Incidental detection of upper gastrointestinal epithelial neoplasia by screening endoscopy
prior to endoscopic ultrasonography in patients with pancreaticobiliary disease
Version: 1 Date: 30 Nov 2023
Reviewer's report:
Title of peer-reviewed paper
Utility of screening esophagogastroduodenoscopy performed sequentially with endoscopic
ultrasonography
Comments
This study is a single-center retrospective analysis paper that shows that endoscopic ultrasound
followed by esophagogastroduodenoscopy(EGD) is useful because it detects more gastric
cancers. In the group that underwent EGD consecutively with endoscopic ultrasonography(EUS)
(N = 615), 10 cases of gastric epithelial neoplasm (1.6%) were detected, which is higher than
the general detection rate1). Also, since it is 0.2% in the target MCC group (N=6763), it seems
that the former is more common. You also created an medical check up center (MCC) group
(N=596) with patient backgrounds from the MCC group and compared the two using propensity
score matching. It has also been pointed out that using a magnifying glass for EGD observation
significantly increases the detection rate of gastric cancer, indicating its usefulness. However,
there are some problems with this research.
First, as an overview, the main point of this paper is that the EGD protocol followed by EUS
seems to be able to detect many gastric cancers, but the gastric cancer detection rate of the EUS
group and MCC matched group with the same subject background is regarding 1.7% vs. 0.7%,
the P value is 0.18, which is not a significant difference. Based on these results, it is questionable
whether it can be concluded that this protocol is useful for detecting gastric cancer. What do
statistical experts think? What about the effects of other confounding factors?
Regarding the patient backgrounds of both groups, it is thought that Helicobacter pylori infection
is strongly involved in the occurrence of gastric cancer, but what about the prevalence of
Helicobacter pylori(HP) and history of eradication in both groups? Based on the atrophy rate
alone, it may be difficult to prove current or past HP infection due to autoimmune gastritis.
If the HP infection status has not been investigated, how about an alternative such as Kyoto
Classification Score2)?
Regarding the MCC group, we assume that the healthy screening group generally includes many
repeat patients who have undergone EGD repeatedly in Japan. The detection rate of gastric
cancer decreases in repeat patients. What do you think of MCC Group's first EGD rate and repeat
customer rate? Also, what is the initial EGD rate and repeat customer rate in the EUS group?
Next, regarding the equipment used, the EUS group mainly used large-diameter pan endoscopes
from Olympus Co. Ltd., including magnification, while the MCC group used small-diameter
trans-nasal endoscopes from Fuji Film Co., Ltd.. These seem to be modalities of quite different
quality. In general, the former has higher image quality and the latter has lower quality. What
do you think about the possibility that there is a difference in the detection rate of gastric cancer
due to these differences in image quality? I think that the use of magnifying glasses in the EUS
group will actually exacerbate the difference in equipment capabilities between the two groups.
Also, what about the use of Image Enhancement Endoscopy(IEE) and the usage rate of indigo
carmine? I think these also make a clear difference in the detection rate of gastric tumors3).
Regarding the timing of EGD testing, how much does the detection rate of gastric cancer differ
between a protocol in which EGD is performed consecutively to EUS and a protocol in which
EGD is performed on another occasion close to the EUS implementation date and time? If there
is no significant difference in detection rate, what is the utility of this sequential testing protocol
other than the fact that two tests can be performed under one pharyngeal anesthesia and sedation?
Can you prove other useful point about the protocol? For example, patient and endoscopist
satisfaction, less frequency of side effects, etc.
As mentioned above, there are some questions in this paper, but it is a positive fact that many
gastric cancers were found using the protocol you proposed, so please take these points into
consideration when revising the content.
## Journal of Gastrointestinal Cancer Screening 2017: 55: 52-83
## Toyoshima O, et al. World J Gastroenterol 2020: 26: 466-477
## Yoshida N, at el. Gut 2011: 70: 67-75