Colorectal Carcinoma Clinical Practice Guidelines (2019)

Association of the Scientific Medical Societies, German Cancer Society, and the German Cancer Aid

This is a quick summary of the guidelines without analysis or commentary. For more information, go directly to the guidelines by clicking the link in the reference.

April 25, 2019

The updated recommendations on the radiologic diagnosis and treatment of colorectal carcinoma (CRC) were released in April 2019 by the Association of the Scientific Medical Societies, German Cancer Society, and the German Cancer Aid.[1]

CT or MR Colonography

Asymptomatic patients should not undergo computed tomography (CT) colonography and magnetic resonance (MR) colonography for colon cancer protection/early detection.

In the setting of incomplete colonoscopy caused by stenosis from a tumor, additional preoperative CT or MR colonography can be performed. In the setting of incomplete colonoscopy for other reasons (eg, adhesions), CT or MR colonography should be performed.


Perform abdominal ultrasonography and conventional chest x-ray on two levels as basic examinations for preoperative CRC staging.

Perform multi-slice CT (MSCT) scanning of the abdomen and pelvis in the setting of an unclear finding or when distant metastases or infiltration of neighboring organs or surrounding structures is suspected, and perform chest CT scanning when lung metastases are suspected.

CT examination for preoperative staging can be used to differentiate between tumors limited to the intestinal wall and those that extend beyond it. However, it is significantly more difficult to identify nodal status. The best results are provided by MSCT.

Positron emission tomography (PET)/PET-CT scanning is not useful for staging in the initial diagnosis of CRC. PET-CT scanning can be performed in CRC patients with resectable liver metastases with the goal to avoid an unnecessary laparotomy. Do not perform PET-CT scanning within 4 weeks after the administration of systemic chemotherapy or antibody therapy because there is a significant reduction in sensitivity.

MR imaging (MRI) should preferably be performed for the local staging of rectal cancer, whereas endoscopic ultrasonography (EUS) should be performed when T1 carcinoma is suspected.

CT scanning is not suitable for T1 carcinomas.

The imaging report should include a statement regarding the distance of the tumor from the mesorectal fascia. Do not use the radial distance of the primary tumor (or affected lymph nodes) from the mesorectal fascia measured on thin-slice MRI (ie, MR circumferential resection margin [mrCRM]) as a decision criterion for primary surgery outside of studies.

All imaging methods are subject to significant diagnostic uncertainty in the evaluation of lymph node status.


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