Confocal chromolaser endomicroscopy: a supplemental diagnostic tool prior to transanal endoscopic microsurgery of rectal tumors

Purpose Due to diagnostic advancements, preoperative staging of rectal tumors was significantly improved. However, difficulties in obtaining accurate results can sometimes be observed in the staging of adenomas and early rectal carcinomas (pT1/2). The aim of this study was to test if confocal chromolaser endomicroscopy (cCLEM) can help minimize this diagnostic gap. Methods cCLEM generates optical transversal sections at ×1,000 magnification and allows for evaluation of the mucosal microarchitecture and differentiation of normal mucosa from adenomas and carcinomas. Cases with conflicting preoperative findings (adenoma vs. ≥uT2 categories), undetectable tumors after inadequate (R1/RX) snare polypectomy of carcinomas, and extremely flat adenoma areas were studied. Results By cCLEM, in ≥uT2 carcinomas with an adenoma histology, malignoma-suspicious areas were identified and selected biopsies were done. In addition, re-epithelialized polypectomy areas of carcinomas were visualized and targeted reoperations could be carried out. Furthermore, the dignity and extension of extremely flat adenomas were determined and marked by clips for additional therapy. Conclusions In cases with rectal tumors, conflicting or unclear findings, and flat extending adenomas, the utilization of cCLEM should be considered. Especially in cases with early rectal carcinomas, unnecessary second operations and also recurrences can be minimized or even avoided by selective usage of cCLEM.