GASTROENTEROLOGY:窄带成像(NBI)光学活检训练效果不佳

　　斯坦福大学的Uri Ladabaum博士及其同事在《胃肠病学》杂志1月刊发表的一项研究显示，12位社区胃肠病医生在完成窄带成像(NBI)光学活检计算机自我培训项目后，仅有3位能够对≤5 mm的结肠息肉达到90%的评估准确率(Gastroenterology 2013;144:81-91)。

　　这一表现不及临床研究中专家评估报告的数据，而与大学医学中心的学生报告结果类似。作者认为，虽然令人“鼓舞”的是有3位胃肠病医生学会了如何应用NBI技术进行光学活检，但仍需提高该方法的效果才能用于社区常规息肉评估实践。美国消化内镜学会(ASGE)推荐微小结直肠息肉腺瘤性组织学光学活检阴性预测值应≥90%。

　　研究者评价了该项旨在用于工作繁忙的社区胃肠病医生自我训练项目的实用性。学员均无明显丰富经验，此前均未接受过NBI培训。

　　学员首先在项目培训的第一周借助计算机自主完成3个单元的学习：学前测验、学习模块(应用NBI区分腺瘤和增生性息肉)以及学后测验。2次测验选取25个不同的内镜息肉影像，要求学员判断它们是腺瘤还是增生性息肉，或表明不能作出判断。然后，要求学员将NBI光学活检应用于结肠镜检查并至少切除1例息肉，记录每个病变的位置、大小和形态学特征，分别以白光和NBI模式成像，并记录他们预测的自信水平(高或低)。

　　在检查完标本并经GI住院病理医生分类后，要求学员记录每个病变的真实诊断结果，并鼓励将其与光学诊断结果进行比较。学员每隔1~2周收到对他们工作准确性的私下反馈。

　　息肉按照大小分为微小(≤5 mm)、小(6~9 mm)或大(≥10 mm)息肉。最初分析仅限于学员对微小息肉光学诊断的准确率，而最终评价则在学员至少完成90例病变组织评估后进行。

　　12位学员接受了体外和体内学习阶段的训练项目，共计完成1,673次结肠镜检查，2,596例息肉切除，其中包括1,858枚微小息肉、547枚小息肉和177枚大息肉，以及14枚未记录大小的息肉。

　　结果显示，所有12位学员经过计算机训练后的测试准确率≥90%，但仅有3位学员在临床实践中仍表现优异，其余9位应用NBI评估微小息肉组织学的准确率未达到≥90%。学员没有表现出典型的学习曲线，未见早期学习与后期高水平稳定性表现之间存在明显关联。此外，认为有可能影响学员准确判断的许多因素被证实并非如此，结肠息肉位置、工作年限和结肠镜检查经验、学习前后测验成绩的变化均与最终光学活检准确性无关。可预测准确性的一个因素是学员对每次预测的自信程度。

　　作者指出，部分学员完成最初计算机训练后并没有坚持完成体内学习阶段的培训，因此需要开发激励机制，鼓励工作繁忙的临床医生学习并应用光学活检技术。总之，该研究表明社区胃肠病医生通过计算机模式自主训练，体外评估可以达到较高的准确性，但他们最终的熟练程度是否取决于技术问题、奉献精神、主动性或个人天赋尚有待观察。

　　该研究由斯坦福大学资助。作者之一报告接受了奥林巴斯公司的研究资助并担任该公司代言人。

Real-Time Optical Biopsy of Colon Polyps With Narrow Band Imaging in Community Practice Does Not Yet Meet Key Thresholds for Clinical Decisions

Background & Aims

Accurate optical analysis of colorectal polyps (optical biopsy) could prevent unnecessary polypectomies or allow a “resect and discard” strategy with surveillance intervals determined based on the results of the optical biopsy; this could be less expensive than histopathologic analysis of polyps. We prospectively evaluated real-time optical biopsy analysis of polyps with narrow band imaging (NBI) by community-based gastroenterologists.

Methods

We first analyzed a computerized module to train gastroenterologists (N = 13) in optical biopsy skills using photographs of polyps. Then we evaluated a practice-based learning program for these gastroenterologists (n = 12) that included real-time optical analysis of polyps in vivo, comparison of optical biopsy predictions to histopathologic analysis, and ongoing feedback on performance.

Results

Twelve of 13 subjects identified adenomas with >90% accuracy at the end of the computer study, and 3 of 12 subjects did so with accuracy ≥90% in the in vivo study. Learning curves showed considerable variation among batches of polyps. For diminutive rectosigmoid polyps assessed with high confidence at the end of the study, adenomas were identified with mean (95% confidence interval [CI]) accuracy, sensitivity, specificity, and negative predictive values of 81% (73%–89%), 85% (74%–96%), 78% (66%–92%), and 91% (86%–97%), respectively. The adjusted odds ratio for high confidence as a predictor of accuracy was 1.8 (95% CI, 1.3–2.5). The agreement between surveillance recommendations informed by high-confidence NBI analysis of diminutive polyps and results from histopathologic analysis of all polyps was 80% (95% CI, 77%–82%).

Conclusions

In an evaluation of real-time optical biopsy analysis of polyps with NBI, only 25% of gastroenterologists assessed polyps with ≥90% accuracy. The negative predictive value for identification of adenomas, but not the surveillance interval agreement, met the American Society for Gastrointestinal Endoscopy–recommended thresholds for optical biopsy. Better results in community practice must be achieved before NBI-based optical biopsy methods can be used routinely to evaluate polyps; ClinicalTrials.gov number, NCT01638091.