Rectal tumour

Rectoscopy revealed a 4cm tumour in the lower rectum.

Before treatment, high-resolution magnetic resonance imaging (MRI) of the pelvis was performed. On T2-weighted images, a 4cm polypoid tumour in the lower rectum was found. The tumour did not seem to invade the propria muscle layer of the rectum, nor to infiltrate the perirectal fat. No malignant lymph nodes could be observed. The MR findings were consistent with a T0-T1N0 tumour according to the TNM-classification (UICC).

After preoperative radiotherapy, the tumour was transanally resected.

For many years, clinical examination by digital examination, rectoscopy and histological analysis of a biopsy specimen was considered to be sufficient for treatment planning.

Now, new imaging techniques such as endorectal ultrasonography, computed tomography and magnetic resonance imaging allow presurgical assessment of tumour spread and metastatic pathways. These can greatly improve tumour staging in the individual patient. The particular benefit of ultrasonography is the possibility of visualising up to five layers of the rectal wall and thus determining the degree of tumour infiltration within the rectal wall. Tumours limited to the mucosa and submucosa (T0-T1) without lymph node metastases may be locally resected.

MRI is being used more and more in preoperative evaluation since the relationship between the tumour, the rectal wall and the mesorectal fascia can be visualised. The mesorectal fascia constitutes the surgical resection plane when performing a total mesorectal excision of the rectum. If this resection plane is involved by tumour, the risk of local tumour recurrence is high.