[Diagnosis and staging of colorectal cancer]

Colorectal cancer is a frequent disease in Norway. New and improved surgical techniques and the implementation of adjuvant and neoadjuvant therapy have improved 5-year survival rates significantly. Accurate preoperative assessment of tumour extent is essential for choosing the appropriate therapeutic strategy, and thus for patient prognosis. Both established and recent imaging methods are presented and discussed.

This review is based on a selection of articles from Pub-Med, with an emphasis on meta-analyses and prospective investigations, and on the clinical experiences of the authors.

Recto-/colonoscopy with biopsy is still the most common approach for diagnosis. In Norway, magnetic resonance imaging (MRI) is the preferred imaging modality for rectal cancer. With optimal technique MRI provides a good visualisation of important local prognostic factors. Endoscopic ultrasound is the modality of choice for small, superficial tumours. The role of multidetector computer tomography (MDCT) in the local evaluation of rectal cancer is not entirely established. The evaluation of metastases of regional lymph nodes is a challenge with all the available imaging modalities. CT-colonography is a recent method for imaging of the colon. It provides an accurate evaluation of the bowel, of tumour invasion outside the bowel wall and of extracolonic (glandula- and liver-) metastases. Double-contrast barium enema, or abdominal and pelvic CT are alternative methods for evaluation of colon cancer. CT of the thorax and abdomen is recommended for screening of distant metastasis.