BACKGROUND/AIMS: Conventional endoscopic ultrasonography was a valuable modality in staging the invasion depth of colon cancer. However, it is not widely used because of its difficulty in detecting small or flat lesions and obtaining a cross-sectional image due to tight stricture of tumor lesions and in those lesions located at or over a bend of the colon. Due to this, mistaging or understaging is often seen. We conducted a prospective study using a new technique and instrument (balloon sheath with miniprobe) in colon cancer staging and compared it with the conventionally used endosonography. METHODOLOGY: One hundred and thirty-four patients underwent preoperative staging using two different instruments. Seventy-three patients were evaluated with conventional endoscopic ultrasonography while the other 61 patients were evaluated with the balloon sheath miniprobe. RESULTS: The balloon sheath miniprobe had an overall accuracy rate of 85%; 100% in T1; 78% in T2; 90% in T3 and 40% in T4. Lymph node metastasis was correctly determined in 67% with a sensitivity and specificity rate of 56% and 75%, respectively. The overall accuracy rate of endoscopic ultrasonography in staging colon carcinoma was 89%; 83% in T1; 83% in T2; 93% in T3 and 71% in T4. Overall accuracy rate in lymph node metastasis evaluation was 77%. Sensitivity was 77% and specificity was 76%. Inability to obtain a clear cross-sectional image using the miniprobe was 3.3%, while that of the endoscopic ultrasonography was 11%. CONCLUSIONS: The balloon sheath miniprobe is a good alternative for evaluating lesions over the proximal colon and is superior to other modalities in obtaining a cross-sectional image even in tight, stenotic lesions. One limitation is its difficulty in assessing deeper structures such as lymph node groups and contiguous organ involvement.
BACKGROUND/AIMS: Conventional endoscopic ultrasonography was a valuable modality in staging the invasion depth of colon cancer. However, it is not widely used because of its difficulty in detecting small or flat lesions and obtaining a cross-sectional image due to tight stricture of tumor lesions and in those lesions located at or over a bend of the colon. Due to this, mistaging or understaging is often seen. We conducted a prospective study using a new technique and instrument (balloon sheath with miniprobe) in colon cancer staging and compared it with the conventionally used endosonography. METHODOLOGY: One hundred and thirty-four patients underwent preoperative staging using two different instruments. Seventy-three patients were evaluated with conventional endoscopic ultrasonography while the other 61 patients were evaluated with the balloon sheath miniprobe. RESULTS: The balloon sheath miniprobe had an overall accuracy rate of 85%; 100% in T1; 78% in T2; 90% in T3 and 40% in T4. Lymph node metastasis was correctly determined in 67% with a sensitivity and specificity rate of 56% and 75%, respectively. The overall accuracy rate of endoscopic ultrasonography in staging colon carcinoma was 89%; 83% in T1; 83% in T2; 93% in T3 and 71% in T4. Overall accuracy rate in lymph node metastasis evaluation was 77%. Sensitivity was 77% and specificity was 76%. Inability to obtain a clear cross-sectional image using the miniprobe was 3.3%, while that of the endoscopic ultrasonography was 11%. CONCLUSIONS: The balloon sheath miniprobe is a good alternative for evaluating lesions over the proximal colon and is superior to other modalities in obtaining a cross-sectional image even in tight, stenotic lesions. One limitation is its difficulty in assessing deeper structures such as lymph node groups and contiguous organ involvement.