MRI Imaging or CT Abdomen as Standard Work-up Before Treatment Planning for Rectal Cancer?

Rectal cancer is a common diagnosis. The prognosis after treatment has improved over the last decades, partly due to neoadjuvant radio(chemo)therapy, but also due to improved surgical technique (TME) and, in certain cases, due to adjuvant therapy after surgery. For some 15-20 years, treatment of metastasis has changed; liver- and lung metastasis in certain situations are surgically removed, or in the liver, treated with ablation (radio-frequency). During the same period the possibilities for chemotherapy of metastatic disease have improved, with new drugs and more drug regimens. These changes in treatment pathways have required changes in how patients with newly diagnosed rectal cancer are "worked up" pre-treatment. Starting in the early 2000s magnetic resonance imaging of the pelvic area has developed and is today mandatory to be able to adequately stage the tumour and plan for the multi-modal treatment before and after surgery. In many hospitals the set-up is a combination of computed tomography of the abdomen and chest and to this a MRI of the pelvic organs is added, whereas others have adopted MRI also for the abdominal part, thus having an MRI of the liver for the diagnosis of liver metastasis initially, before surgery. For the chest organs, CT is still normative. MRI has a higher sensitivity and specificity to detect liver metastasis, compared with CT. In order to plan the liver surgery/ablations, most liver surgeons rely on MRI for detailed information about the position of the metastasis and the relation to large vessels. The aim of this study is to examine the possible differences in percentage of patients requiring further radiology examinations after basic set-up comparing the routine of initial MRI of abdomen (and pelvic organs) with the routine of initial CT of the abdomen (and MRI of the pelvic organs). Further included is an analysis of the rate of liver metastasis using the two different routines, and finally outcome over 12 months in terms of liver treatment for metastasis.

Sex

All

Inclusion Criteria:

* All patients in the Swedish Colo- Rectal Cancer Registry (SCRCR) and treated for rectal cancer at Sahlgrenska University Hospital and Norra Älvsborg Hospital 2013-2015.

Exclusion Criteria:

* None

• DERIVEDPark J, Block M, Bock D, Kalebo P, Nilsson P, Prytz M, Haglind E. A Comparison of Liver MRI and Contrast-Enhanced CT as Standard Workup Before Treatment for Rectal Cancer in Usual Care - A Retrospective Study. Curr Med Imaging. 2022;18(2):256-262. doi: 10.2174/1573405617666210712125028. PMID 34931986