新内镜技术可避免对所有息肉进行病理检查

圣迭戈(EGMN)——加州退伍军人医学中心的Tonya Kaltenbach博士在美国消化疾病周(DDW)上报告，高分辨率、双焦点结肠镜的应用使得内镜医生可以在内镜下对小息肉做出明显更准确、更可信的诊断，从而向“不必对结肠镜下切除的每一枚息肉都常规做病理检查”的目标迈出了重要一步。

Roy Soetikno博士、Kaltenbach博士及其同事设计了这项名为退伍军人结直肠病变解释与诊断（VALID）的研究，旨在检验“使用高解析度、窄带成像、双焦点结肠镜可以提高小息肉组织学预测的准确率和可信度”的假设。参加该研究的5名消化病学专家使用高分辨率内镜，在3家美国中心对568名受试者进行了评估。受试者的平均年龄为63岁，男性占95%，约80%为白人。约38%的受试者接受结肠镜筛查，44%因有息肉病史而接受监测，19%因出现症状而接受检查。

经过随机分组，对277人采用CF-HQ190高分辨率双焦点结肠镜进行检查，对281人采用老式的CF-HQ190结肠镜进行检查。结果双焦点组发现了710枚息肉，包括530枚小息肉；对照组发现了599枚息肉，包括445枚小息肉。

内镜医生对75%的双焦点组小息肉做出了准确、可信的预测，而这一比例在对照组仅为63%，差异具有统计学显著性。以病理学评估为参照，对于双焦点组的高可信度小息肉，内镜医生给出的监测间隔建议95.9%是正确的，这一比例在对照组为95.2%，两组的阴性预测值分别为96.4%和92%。此外，双焦点组没有出现将组织学进展期病变误诊为非肿瘤的情况，没有导致检查时间出现任何有意义的增加，也没有引起任何出血或穿孔。

上述性能水平超过了2011年美国胃肠内镜学会(ASGE)设定的结肠镜评估小息肉准确率达到90%的目标（Gastrointest. Endosc. 2011;73:419-22）。主要研究者Soetikno博士在接受采访时指出，值得注意的是，息肉切除术后监测准确率和阴性预测值90%的阈值，是在双焦点结肠镜被广泛使用之前设定的。他预计在未来5年内，美国使用的的结肠镜都将具备高分辨率、双焦点的性能特征。

“在许多医院，小结肠息肉约占所有病理标本的20%~25%，而且几乎都是良性的。这是有可能节省下来的一大笔费用。在结肠镜筛查中发现的息肉约80%为直径≤5 mm的小息肉，目前的标准做法是对每一枚这类息肉都做病理学分析。” 视觉评估潜在癌变或癌前病变并不是个新想法，因为这已经成为了皮肤科的常规做法。凭借新技术，消化医生“或许能做同样的事情，从而节省医疗资源，而不是把钱花在评估无关紧要的息肉上”。

不过Soetikno博士承认，尽管这项新研究表明内镜医生的表现可以超过ASGE设定的视觉评估阈值，但这一方法还有待进一步验证才能被广泛使用。“我们需要制定消化科医生培训计划，还需要更好的图像存储方法。不过，我们的研究是个好的开始。”

宾夕法尼亚大学的Michael L. Kochman博士认为，上述研究结果表明，内镜医生的确可以看到并准确预测结直肠息肉的组织学特性且不引起任何严重不良后果。然而，尽管该技术在本研究中取得了成功，但要将其推广到常规实践中还为时尚早。鉴于医生们在参加研究时往往比在日常实践中表现更好，他担心如果推广该技术，其表现可能会不尽人意。他同意Soetikno博士的建议，即在对大量内镜医生进行充分培训后再将该技术引入常规实践。

VALID研究从奥林巴斯美国分公司获得了部分资助，该公司是双焦点、高分辨率结肠镜的生产商。Soetikno博士报告称担任奥林巴斯的顾问。Kaltenbach博士和Kochman博士报告称无利益冲突。

SAN DIEGO (EGMN) – Researchers have taken a major step toward eliminating the need for routine pathology on every polyp removed during colonoscopy.

Use of a high-definition, dual-focus colonoscope allowed endoscopists to perform “significantly more accurate, high-confidence endoscopic diagnosis of diminutive polyps,” Dr. Tonya Kaltenbach said at the annual Digestive Disease week.

“In many hospitals, about 20%-25% of all pathology samples are small colon polyps, almost all of which are benign. This is a lot of money that can be saved,” said Dr. Kaltenbach in a written statement. About 80% of all polyps found during screening colonoscopy are diminutive, 5 mm in diameter or less, and the current standard of care is to do a pathology analysis on each of these polyps.

As used by five gastroenterologists who participated in the study at three U.S. centers to assess 530 polyps in 277 people, the high-definition scope produced a 95.9% agreement in polyp assignment for follow-up surveillance, compared with pathology-laboratory analysis of the same polyps, and a 96.4% negative predictive value for adenomas, said Dr. Kaltenbach, a gastroenterologist at the VA Medical Center in Palo Alto, California.

These performance levels surpassed the greater than 90% targets for colonoscopic assessment of diminutive polyps set last year by a committee organized by the American Society of Gastrointestinal Endoscopy (Gastrointest. Endosc. 2011;73:419-22). Notably, the 90% threshold for assignment of postpolypectomy surveillance accuracy and negative predictive value was set by the ASGE committee before dual-focus colonoscopies like the one used in the current study were in widespread use, said Dr. Roy Soetikno, chief of endoscopy at the Palo Alto VA and senior investigator on the study. Today, some of the scopes used in routine U.S. practice have the high-definition, dual focus features of the one used in the study, and within the next 5 years essentially all U.S. colonoscopies will have these performance characteristics, he said in an interview.

Although the new study results showed that endoscopists can surpass the thresholds set by the ASGE for visual assessment, widespread use of the method will require further validation, Dr. Soetikno said. “We need to develop programs to teach gastroenterologists and incorporate them into fellowship programs. We also need a way to store the images so that people can document their diagnoses. But [our study] is the beginning,” he said.

Dr. Soetikno also noted that the idea of visual assessment of potentially cancerous or precancerous lesions is not new, as the same approach is routinely used in dermatology. With new technologies, gastroenterologists “may be able to do the same thing. We can save our resources, and not spend money on evaluating polyps of no consequence.”

Dr. Soetikno, Dr. Kaltenbach, and their associates designed the Veterans Affairs Colorectal Lesion Interpretation and Diagnosis (VALID) study to test the hypothesis that colonoscopy using a high-definition, narrow-band imaging, dual focus colonoscope could increase the rate of accurate, high-confidence histology predictions of diminutive polyps. Five endoscopists working at three VA Medical Centers randomized 558 patients scheduled to undergo routine colonoscopy. The patients averaged 63 years old, 95% were men, and about 80% were white. Roughly 38% underwent colonoscopy for screening, 44% for surveillance following a history of polyps, and for 19% the examination was symptom driven (total is 101% due to rounding).

The protocol randomized 277 people to high-definition colonoscopy with an Olympus model CF-HQ190, and 281 people to examination with an older model without dual-focus capability, the Olympus CF-H180. Examination of the people in the dual-focus group found 710 polyps, including 530 diminutive lesions; the control group had 599 polyps, including 445 that were 5 mm or less.

The endoscopists made accurate, high-confidence endoscopic predictions on 75% of the diminutive polyps that they saw using the dual-focus device, compared with a 63% when they used the less advanced endoscope, a statistically significant difference. When compared with the pathologic assessments, 95.9% of the high-confidence, dual-focus diagnoses produced correct surveillance-interval recommendations, compared with a 95.2% rate using the standard-focus device. Negative predictive value was 96.4% using the dual-focus scope and 92.0% for the more conventional scope. In addition, the dual-focus scope produced no misdiagnoses of advanced histology as non-neoplasia, and use of this scope did not result in any meaningful increase in examination time, nor did it produce any bleeding or perforation.

According to Dr. Michael L. Kochman, the findings show that endoscopists really can see and accurately predict the histologic profile of colorectal polyps without producing any major adverse outcomes.

However, despite the success reported in this study, it is premature to extrapolate the efficacy of the colonoscopic methods they used to routine practice, he said during a press conference at the meeting.

Results are always better when physicians participate in a study and know they are being watched, said Dr. Kochman, a gastroenterologist and professor of medicine at the University of Pennsylvania in Philadelphia. We worry that there will be a fall in efficacy as the method diffuses out more widely. A better approach is what Dr. Soetikno suggested: waiting until a generation of endoscopists come into practice who have undergone thorough training with the new, high-definition scopes, he said.

The VALID study received partial funding from Olympus America, the company that markets the dual-focus, high-definition colonoscope tested. Dr. Soetikno said that he has been a consultant to Olympus. Dr. Kaltenbach and Dr. Kochman said they had no disclosures.