[Endosonographic diagnosis in preoperative radiotherapy of locally advanced rectal carcinoma].

Endorectal ultrasound (EUS) is important for the indication of preoperative radio(chemo)therapy of locally advanced rectal carcinomas. Preoperative radio(chemo)therapy causes an increased echogenity of the ultrasound, which histologically corresponds with increased fibrosis. After preoperative radio(chemo)therapy, the accuracy rate of EUS of tumor infiltration depth (T) and lymph-node status (N) is 75% compared with postoperative histology. With the help of EUS before and after radio(chemo)therapy (n = 28 patients) "downstaging" was noticed endosonographically in 10 patients (3 times in T and 7 times in N staging) and "upstaging" in 3 patients (3 times in T and 1 times in N staging). There was no "understaging" of local tumor infiltration depth after preoperative radio(chemo)therapy.