Preoperative evaluation of colorectal neoplasms by colonoscopic miniprobe ultrasonography

Objective To investigate the value of colonoscopic miniprobe ultrasonograph y for preoperative staging of colorectal neoplasms. Summary Background Data Endoscopic ultrasonography is the most accurate tec hnique for staging colorectal cancer. However, limitations of this techniqu e include the inability to examine stenotic tumors and the difficulty of re aching tumors proximal to the rectum. Methods Miniprobe ultrasonography (12.5 MHz) was performed in 63 patients w ith tumors of the colon or rectum. The results of imaging were compared wit h endoscopic assessment of the lesions and histopathologic findings of the resected specimens. Results Miniprobe ultrasonography allowed high-resolution imaging of colore ctal tumors during routine colonoscopy. The infiltration depth was correctl y classified in 22 adenoma, 3 T1, 10 T2, and 22 T3 or T4 tumors. The accura cy for tumors of the rectum and colon was 86% and 92%, respectively (overal l accuracy 90%), The small diameter of the probe allowed examination of 21 stenotic tumors with an accuracy of 86%. Miniprobe ultrasonography revealed carcinoma in 5 of 30 broad-based polyps, although adenomas were diagnosed by endoscopy. Correct assessment of lymph node involvement was obtained in 47 of 55 patients. Based on the findings of miniprobe ultrasonography, management was modified in 7 of the 63 patien ts. Conclusions These preliminary results show that miniprobe ultrasonography i mproves preoperative staging of stenotic rectal cancer and colonic tumors, This technique can be easily performed during routine colonoscopy and may h ave considerable impact on surgical therapy.