Optical Diagnosis of Diminutive Colorectal Polyps: Can Any Old Dog Learn This New Trick?

In this issue of GE – Portuguese Journal of Gastroenterology, Castela et al. [1] report on the diagnostic accuracy of the real-time optical diagnosis of colorectal polyps using the NBI International Colorectal Endoscopic (NICE) and the Workgroup on serrAted polypS and Polyposis (WASP) classification. One of the practical applications of real-time optical diagnosis is implementing the “diagnose-and-leave” and the “resect-and-discard” strategies during screening and surveillance colonoscopies. In the first, diminutive (≤5 mm) rectosigmoid hyperplastic polyps (HPs) are left in situ, as they are considered to have no malignant potential. In the second, diminutive neoplastic colorectal polyps are resected but not sent for histopathological analysis, as they rarely harbor advanced histology (high-grade dysplasia or a villous component), and post-polypectomy surveillance intervals are assigned based on optical diagnosis. This can reduce the cost, risk, and workload associated with colonoscopy. The American Society for Gastrointestinal Endoscopy has defined the minimal thresholds necessary to safely incorporate them in clinical practice: a negative predictive value (NPV) of ≥90% for neoplastic polyps in the “diagnose-and-leave” strategy and a ≥90% agreement between optical-based and pathology-based surveillance intervals for the “resect-and-discard” strategy [2]. In practice, these policies require accurate optical differentiation between nonneoplastic (HPs) and neoplastic lesions (adenomas [ADs] and sessile serrated lesions, SSLs). NICE classification was validated for the optical distinction of HPs and ADs; however, it does not include SSLs. The WASP was developed and validated in 2015 to differentiate SSLs from HPs and ADs [3].