Forward-viewing radial-array echoendoscope for staging of colon cancer beyond the rectum

Table 1 Number of patients with colon cancer classified according to endoscopic ultrasound vs surgical pathological T staging

EUS/Histology	T1	T2	T3	T4	Total
uT1	2	0	0	0	2
uT2	0	3	2	0	5
uT3	1	1	11	0	13
uT4	0	0	0	1	1
Total	3	4	13	1	21

Tumors were pathologically staged as T1 (n = 3), T2 (n = 4), T3 (n = 13) and T4 (n = 1). Ultrasonographic T staging was T1 (n = 2), T2 (n = 5), T3 (n = 13) and T4 (n = 1). EUS: Endoscopic ultrasound; u: Ultrasound; T: Tumor.

Table 2 This table demonstrates the endoscopic ultrasound vs computed tomography staging of colon cancer in comparison with the surgical pathology classified into early (T1/T2) and advanced (T3/T4) stages

Pathological stage	T1/T2	T3/T4	Total
EUS (n = 21)	5	12	17
CT (n = 19)	4	9	13

EUS and CT had overall accuracy rates of 81.1% and 68.4%, respectively. Data from CT was available in 19 patients. EUS: Endoscopic ultrasound; CT: Computed tomography.

Table 3 Diagnostic values of endoscopic ultrasound vs computed tomography scan for staging of colon cancer

Modality	Sensitivity	Specificity	PPV	NPV	Accuracy
EUS (n = 21 )	85.0%	-	94.4%	-	80.9%
CT scan (n = 19)	76.5%	-	86.7%	-	68.4%

EUS: Endoscopic ultrasound; CT: Computed tomography; PPV: Positive predictive value; NPV: Negative predictive value.

Table 4 Advantages and disadvantages of the 3 types of echoendoscopes that have been used for the evaluation of lesions on the colon beyond the rectum

	Advantages	Disadvantages
A miniprobe echoendoscope	Widely available Can be used together with regular colonoscope	Cannot be properly used for evaluation of thickened-wall colon cancer
A forward-viewing linear-array echoendoscope	Ability to perform EUS guided fine needle aspiration for colonic lesions	Inconvenient to evaluate circumferential colonic lesions like colon cancer
A forward-viewing radial-array echoendoscope	Ability to evaluate circumferential colonic lesions	Inability to perform EUS guided FNA for colonic lesions

EUS: Endoscopic ultrasound.