[Initial staging of rectal cancer].

Initial staging of rectal cancer. Rectal cancers are one of the most frequent digestive cancers. Most of them are diagnosed during organized cancer screening or based on evocative symptoms. After a thorough clinical examination including rectal examination, the next step is to confirm the diagnosis by colonoscopy with biopsies. Once diagnosis is confirmed, other imaging exams are necessary to assess loco-re¬gional extension and metastatic spread. Rectal magnetic resonance imaging (MRI) and thoracic-abdominal-pelvic computed tomography (CT) are the modalities of choice, respectively for loco-regional and metastatic spread. MRI protocol is standardized, and its report must provide specific information to guide surgical and non-surgical mana¬gement options (especially tumor localization, local poor prognosis factors and node involvement). Thoraco-abdominal-pelvic CT especially seeks for liver and lung metas¬tasis. Other imaging modalities (such as endoscopic ultrasound and positron emission tomography scan) are reserved for specific cases.