How useful is rectal endosonography in the staging of rectal cancer?

Table 1 Tumor stage on endorectal ultrasound to determine the management strategy, and corresponding survival rates[2,10]

Stage	T and N groups	Management	Five year survival
I	T 1-2, N0, M0	Snare polypectomy, EMR-ESD, TAEX, LAR, APR	> 90%
II	T3 - 4, N0, M0		60%-85%
III	T1-4, N1, M0	LAR, RT followed by APR	25%-60%
IV	T1-4, N0-2, M1	RT-CT followed by APR	5%-7%

N0: No regional lymph node metastasis; N1: Metastasis in one to three regional lymph nodes; N2: Metastasis in four or more regional lymph nodes; EMR: Endoscopic mucosal resection; ESD: Endoscopic submucosal dissection; TAEX: Transanal excision; LAR: Low anterior resection; APR: Abdominoperineal resection; RT: Neoadjuvant radiotherapy; RT-CT: Neoadjuvant radiochemotherapy.