Surgical relevance of diagnostic imaging techniques in pretherapeutic staging of carcinoma of the esophagus, stomach, colon and rectum

Summary. The increasing spectrum of therapeutic options for tumors of the gastrointestinal tract has resulted in a refinement of the pretherapeutic diagnostic strategies. The diagnostic approach in surgical institutions that are focused on primary surgical resection will therefore be much less sophisticated than in institutions who propose a selective therapeutic approach based on the pretherapeutic tumor stage and prognostic parameters. Pretherapeutic assessment of the depth of tumor infiltration, i. e. the T-category, is essential because most further diagnostic and therapeutic decisions are based on this information. This can today be achieved with a high degree of accuracy by endoscopy and endoscopic ultrasonography. Early T-stages (T1–2) are usually an indication for primary surgical resection and, after exclusion of distant metastases, no further diagnostic studies are required. In patients with locally advanced esophageal, gastric or rectum tumors (T3–4) multimodal therapeutic concepts should be considered. This usually requires additional diagnostic studies. None of the available diagnostic imaging modalities today allows satisfactory pretherapeutic assessment of lymph node metastases. The assumed nodular status should therefore currently not influence therapeutic decisions. Essential is, however, the assessment of distant metastases, since the documentation of distant tumor spread will change the therapeutic approach to a palliative situation. Detailed histologic and molecular-biologic assessment of tumor characteristics is growing in importance. This not only provides therapeutically relevant information regarding tumor grading, but opens the door towards a modern molecular diagnostic approach. It can be expected that in the near future a vast amount of relevant prognostic information can be obtained from endoscopic tumor biopsies, which may soon alter our therapeutic concepts.