Determining the treatment strategy for colorectal neoplastic lesions: endoscopic assessment or the non-lifting sign for diagnosing invasion depth?

Background and study aims: Assessment of the invasion depth of colorectal neoplasia is important in deciding between endoscopic and surgical resection treatment methods. Prior to attempting endoscopic resection, the lesion is lifted by submucosal injection, and a positive "non-lifting sign" is usually considered to indicate deeper submucosal infiltration. The purpose of this prospective multicenter study was to assess the predictive value of the non-lifting sign for differentiating between adenoma and early cancer (up to discrete submucosal infiltration [sm1]) and cancer with deeper infiltration (sm2). Patients and methods: During an 11-month period, a total of 271 colorectal neoplastic lesions in 239 patients were included in the study. Apart from the location, size, and macroscopic type of the lesion, the presence or absence of the non-lifting sign was recorded and compared with the endoscopic assessment of invasion depth. Results: The non-lifting sign had a sensitivity of 61.5%, a specificity of 98.4%, a positive predictive value of 80.0%, a negative predictive value of 96.0%, and an accuracy of 94.8%. Endoscopic diagnosis of deeper infiltration had a sensitivity of 84.6%, a specificity of 98.8%, a positive predictive value of 88.0%, a negative predictive value of 98.4%, and an accuracy of 97.4%. Statistically significant differences were found in terms of sensitivity and accuracy. Conclusion: Because of its lower sensitivity and accuracy, the non-lifting sign will not replace endoscopic assessment. If a lesion does not lift, this can make resection technically difficult, but does not reliably predict deeper cancerous invasion.