Outcomes of endoscopic submucosal dissection for different subtypes of colorectal laterally spreading tumors / 中华消化内镜杂志

ABSTRACT

Objective To investigate the clinicopathological features of specific subtypes of laterally spreading tumor (LST) and assess the outcomes of endoscopic submucosal dissection (ESD) based upon differentiation status.Methods A total of 174 cases of colorectal LST,treated with ESD between January 2007 and April 2011,were divided into granular type (LST-G) and non-granular type ( LST-NG),and further divided into 4 subtypes,including homogeneous granular,nodular mixed,flat elevated and pseudo-depressed types.Clinicopathological data and ESD parameters were compared between the four subtypes.Results Nodular mixed tumors were larger than homogeneous tumors,needed longer operation time and were more frequently seen in malignant transformation,high grade intraepithelial neoplasm ( HGIN ) as well as submucosal invasive cancer.So were peeudo-depressed tumors compared with flat elevated ones ( P ＜0.01 ).There was no significant difference between LST-G and LST-NG in the parameters of ESD including en bloc resection rate,complete resection rate and complete cure resection rate.The complications tended to be more frequent in nodular mixed tumors (bleeding rate4.6％; peroration rate3.5％ ) and pseudo-depressed tumors ( bleeding rate11.1％ ; perforation rate 11.1％ ),but there was no severe complication in either homogeneous tumors or fiat elevated tumors.One recurrent pseudo-depressed tumor was found 6 months after ESD treatment.Conclusion The degree of technical difficulty appears higher for nodular mixed and pseudo-depressed tumors than for homogeneous and flat elevated tumors,as is shown in procedure time and complication rate.ESD for these two subtypes should better be performed by experienced endoscopists.Accurate differentiation of the LST lesions is needed in basic and clinical research.