Preoperative evaluation of submucosal invasive colorectal cancer using a 15-MHz ultrasound miniprobe

Background and Study Aims: Recently, it was reported that focal submucosal invasive colorectal cancer could be treated by polypectomy or endoscopic mu cosal resection (EMR) because of the rarity of lymph-node metastasis, Our o bjective was to examine the accuracy and efficacy of a 15-MHz ultrasound mi niprobe in the preoperative evaluation of the degree of submucosal invasion in colorectal cancer. Patients and Methods: A total of 35 patients with submucosal invasive color ectal cancer who underwent ultrasonography with a miniprobe were studied pr ospectively, The results of this imaging were compared with the histologic findings in resected specimens. Results: Although the accuracy of the miniprobe in categorizing submucosal invasion into three subclasses (SM1, invasion limited to the upper third; S M2, limited to the middle third; SM3, limited to the lower third) was low ( 37.1%; 13/35), the accuracy in differentiation between less than or equal t o SM1 (M and SM1) and greater than or equal to SM2 (SM2, SM3, MP, and S) wa s 85.7 % (30/35), Conclusions: The miniprobe can be useful for therapeutic decision-making in submucosal invasive colorectal cancer.