Table 3.

T staging (uT) of rectal cancer at endoscopic ultrasound, according to the infiltration depth

uT1 = tumor invasion limited to the mucosa and the submucosa; this is further divided into T1m, if the tumor infiltrates the mucosa, with normal muscolaris mucosa, and T1sm, when there is submucosal invasion (Figures 1 and 7)

uT2 = tumor infiltration of the muscolaris propria, with the tumor mass extended through the first 4 layers of the rectal wall. The outer layer corresponding to the muscolaris propria is smooth, meaning that the tumor is still limited to the rectal wall (Figure 2)

uT3 = tumor invasion of the perirectal fat, with an irregular 4th layer, which means that the tumor has spread outside the rectal wall (Figures 3 and 4)

uT4 = tumor infiltration of adjacent structures and organs, which are strictly connected to the rectal hypoechoic mass (Figure 5)

From ref.[9].