【medical-news】发现高危的胃癌前病变犹如大海捞针
发布于 2008-06-30 · 浏览 1178 · IP 吉林吉林
这个帖子发布于 16 年零 308 天前，其中的信息可能已发生改变或有所发展。
Finding the needle in the haystack: identifying the high-risk “premalignant” gastric lesion
Richard E. Sampliner, MD
Abbreviation: NBI, narrow-band imaging
Article Outline
• Disclosure
• References
• Copyright
Is the premalignant lesion to be detected the readily recognized intestinal metaplasia or the more difficult to detect dysplasia?
In this month's Gastrointestinal Endoscopy, authors of an article from Portugal (where gastric cancer ranks as the cancer with the second-highest incidence) attempt the “external validation of a classification for methylene blue magnification chromoendoscopy in premalignant gastric lesions.”1 This article raises issues that need to be addressed: finding the premalignant lesion in the haystack of the stomach, finding the premalignant lesion in the haystack of the population and whether methylene blue with magnification is the method of choice for detection.
As the elegant methylene blue images demonstrate in this article, metaplastic and dysplastic mucosa can be identified with magnification endoscopy. Yet is the premalignant lesion the readily recognized intestinal metaplasia or the more difficult to detect dysplasia? Gastric intestinal metaplasia is a common finding in countries with a high prevalence of Helicobacter pylori infection.2 H pylori chronic active gastritis, gastric atrophy, intestinal metaplasia, and dysplasia are well-recognized sequential events in the development of intestinal-type gastric adenocarcinoma.
Dysplasia clearly represents the greatest risk for subsequent development of cancer, certainly more than gastric intestinal metaplasia. Unfortunately, methylene blue magnification chromoendoscopy detected only 1 of 3 patients with biopsy-documented dysplasia. There was greater sensitivity in identifying gastric atrophy and intestinal metaplasia, 86% and 81%, respectively. A sample of 3 patients, however, is inadequate to evaluate the sensitivity of this endoscopic method for the real-time detection of dysplasia.
The patients in this study also are an example of the difficulty of defining the at-risk population in the haystack of adults in a country. Although 9 of the 42 patients had prior endoscopic removal of a gastric neoplastic lesion, only 3 had dysplasia. This study highlights the problem of “validating” a technique in a cross-sectional study that may be more representative of a screening population and appropriate to investigate. The problem is the low prevalence of the premalignant lesion being assessed (ie, dysplasia in gastric intestinal metaplasia). The low histologic yield of dysplasia was in spite of biopsies of standard locations (antrum, incisura, and body) and targeted biopsies of methylene blue stained and unstained areas. A total of more than 11 biopsy specimens were taken per patient. This imaging technique will not be applicable to a lower-risk population (for gastric intestinal metaplasia and dysplasia), such as the population in the United States.3
Turning to the chromoendoscopy technique: chromoendoscopy is a disappearing art in the era of high-resolution endoscopy and narrow-band imaging (NBI).4 With the ready availability of NBI in the United States, chromoendoscopy is unlikely to be used. NBI is more available than magnification endoscopy, although it is not yet validated as a technique. In the study of Areia et al,1 a median of 11 minutes was spent on methylene blue staining and 5 minutes for magnification. Such extended time at endoscopy must be justified by a high and important yield, and this will not be possible for dysplasia in gastric intestinal metaplasia. The 1% concentration of methylene blue used in this study is double that used in the United States.5 This is especially an issue given the concern raised about DNA damage.6 Additionally, this imaging technique does not have adequate performance characteristics to provide a short cut for defining a high-risk patient subgroup.
Although theoretically methylene blue staining provides the red flag technology for intestinal metaplasia, as demonstrated in the images, the dysplastic areas are less intensely stained and are apparently viewed with higher magnification. We need more sensitive, user-friendly, and less time-intense techniques to identify those at greatest risk of gastric adenocarcinoma for early endoscopic intervention or chemoprevention.
Richard E. Sampliner, MD
Abbreviation: NBI, narrow-band imaging
Article Outline
• Disclosure
• References
• Copyright
Is the premalignant lesion to be detected the readily recognized intestinal metaplasia or the more difficult to detect dysplasia?
In this month's Gastrointestinal Endoscopy, authors of an article from Portugal (where gastric cancer ranks as the cancer with the second-highest incidence) attempt the “external validation of a classification for methylene blue magnification chromoendoscopy in premalignant gastric lesions.”1 This article raises issues that need to be addressed: finding the premalignant lesion in the haystack of the stomach, finding the premalignant lesion in the haystack of the population and whether methylene blue with magnification is the method of choice for detection.
As the elegant methylene blue images demonstrate in this article, metaplastic and dysplastic mucosa can be identified with magnification endoscopy. Yet is the premalignant lesion the readily recognized intestinal metaplasia or the more difficult to detect dysplasia? Gastric intestinal metaplasia is a common finding in countries with a high prevalence of Helicobacter pylori infection.2 H pylori chronic active gastritis, gastric atrophy, intestinal metaplasia, and dysplasia are well-recognized sequential events in the development of intestinal-type gastric adenocarcinoma.
Dysplasia clearly represents the greatest risk for subsequent development of cancer, certainly more than gastric intestinal metaplasia. Unfortunately, methylene blue magnification chromoendoscopy detected only 1 of 3 patients with biopsy-documented dysplasia. There was greater sensitivity in identifying gastric atrophy and intestinal metaplasia, 86% and 81%, respectively. A sample of 3 patients, however, is inadequate to evaluate the sensitivity of this endoscopic method for the real-time detection of dysplasia.
The patients in this study also are an example of the difficulty of defining the at-risk population in the haystack of adults in a country. Although 9 of the 42 patients had prior endoscopic removal of a gastric neoplastic lesion, only 3 had dysplasia. This study highlights the problem of “validating” a technique in a cross-sectional study that may be more representative of a screening population and appropriate to investigate. The problem is the low prevalence of the premalignant lesion being assessed (ie, dysplasia in gastric intestinal metaplasia). The low histologic yield of dysplasia was in spite of biopsies of standard locations (antrum, incisura, and body) and targeted biopsies of methylene blue stained and unstained areas. A total of more than 11 biopsy specimens were taken per patient. This imaging technique will not be applicable to a lower-risk population (for gastric intestinal metaplasia and dysplasia), such as the population in the United States.3
Turning to the chromoendoscopy technique: chromoendoscopy is a disappearing art in the era of high-resolution endoscopy and narrow-band imaging (NBI).4 With the ready availability of NBI in the United States, chromoendoscopy is unlikely to be used. NBI is more available than magnification endoscopy, although it is not yet validated as a technique. In the study of Areia et al,1 a median of 11 minutes was spent on methylene blue staining and 5 minutes for magnification. Such extended time at endoscopy must be justified by a high and important yield, and this will not be possible for dysplasia in gastric intestinal metaplasia. The 1% concentration of methylene blue used in this study is double that used in the United States.5 This is especially an issue given the concern raised about DNA damage.6 Additionally, this imaging technique does not have adequate performance characteristics to provide a short cut for defining a high-risk patient subgroup.
Although theoretically methylene blue staining provides the red flag technology for intestinal metaplasia, as demonstrated in the images, the dysplastic areas are less intensely stained and are apparently viewed with higher magnification. We need more sensitive, user-friendly, and less time-intense techniques to identify those at greatest risk of gastric adenocarcinoma for early endoscopic intervention or chemoprevention.
最后编辑于 2022-10-09 · 浏览 1178
3 收藏点赞
