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 mucosal resection (EMR) because of the rarity of lymph-node metastasis. Our objective was to examine the accuracy and efficacy of a 15-MHz ultrasound miniprobe in the preoperative evaluation of the degree of submucosal invasion in colorectal cancer.

Patients and Methods: A total of 35 patients with submucosal invasive colorectal cancer who underwent ultrasonography with a miniprobe were studied prospectively. 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; SM2, limited to the middle third; SM3, limited to the lower third) was low (37.1 %; 13/35), the accuracy in differentiation between ≤ SM1 (M and SM1) and ≥ SM2 (SM2, SM3, MP, and S) was 85.7 % (30/35).

Conclusions: The miniprobe can be useful for therapeutic decision-making in submucosal invasive colorectal cancer.

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