Magnetic Resonance Imaging or Contrast-Enhanced Computed Tomography of the Liver as Standard Workup Before Treatment for Rectal Cancer

ABSTRACT Magnetic Resonance Imaging or Contrast-Enhanced Computed Tomography of the Liver as Standard Workup Before Treatment for Rectal Cancer Mathias Utterberg, Degree Project in Medicine, 2018 Department of Surgery, Sahlgrenska Academy, University of Gothenburg, Sweden Supervisor: Eva Haglind Introduction: The liver is the most commonly affected site regarding rectal cancer metastasis. The Swedish national cancer care guidelines recommend a routine of a preoperative contrast-enhanced computed tomography (CT) to examine the liver for metastases before rectal cancer treatment. The NU Hospital Group (NU) conforms to the national guidelines. The Sahlgrenska University Hospital (SU) differs by conducting magnetic resonance imaging (MRI) of the liver. Objective: To compare the efficiency of MRI with contrast-enhanced CT as the index examination of the liver in patients with newly diagnosed rectal cancer. Methods: Clinical data regarding 320 patients with rectal cancer (160 from SU and 160 from NU) were collected from the Regional ColoRectal Cancer Register, 2013–2015. Information regarding such as liver examinations and surgery was collected from hospital records. All index liver examinations that did not confirm or rule out liver metastasis were considered “inconclusive” and subsequently re-evaluated by two radiologists. Results: 274 patients were analyzed. 13 % in the MRI group and 15 % in the CT group underwent supplementary liver examinations before treatment for rectal cancer (p = 0.635). Within 18 months after the index examination, a total of 17 % of patients were diagnosed with liver metastases in both groups combined (p = 0.765), and 8 % of patients in the MRI group versus 2 % in the CT group were treated with liver surgery (p = 0.016). Conclusions: MRI did not show any clinical advantage over contrast-enhanced CT as the index examination of the liver among patients with newly diagnosed rectal cancer. Thus, this study gives no reason to change the current Swedish national guidelines for rectal cancer