USEFULNESS OF (18)FDG POSITRON-EMISSION-TOMOGRAPHY IN DETECTION AND FOLLOW-UP OF DIGESTIVE CANCERS

PET is a diagnostic method that creates high resolution, 3 dimensional tomographic images of the distribution of positron emitting radionucl ides in the human body, Recent technological developments allow the us e of whole-body PET devices in clinical oncology. (18)FDG is a glucose analog transported and competitively used with glucose reflecting the increased glucose metabolism into malignant cells. Differential diagn osis between chronic pancratitis and pancreatic cancer is already a we ll-documented indication. For initial staging of gastro-esophageal and colorectal tumours, results are preliminary but the clinical impact s eems to be rather limited. At present, the major indication of FDG-PET is the dectection and staging of colorectal cancer recurrences, FDG-P ET allows the differentiation between scared tissue and tumour when st ructural imaging is often confusing, In the same time, the whole-body imaging capability provides unique information that can modify loco-re gional and liver staging, Overall, FDG-PET affects the clinical manage ment of 30 to 40% of these patients. Quantitative assessment of therap eutic response to chemotherapy regimen appears to be one of the most p romising applications of FDG-PET, Since the most effective therapy of colorectal cancer are often surgical, the role of chemotherapy in colo rectal cancer remains Limited to adjuvant therapy and in advanced dise ase, However, FDG-PET could be of great value in assessing the respons e of oesophageal carcinomas to chemo-radio therapy, before surgery. In our experience, FDG-PET appears to be the first line diagnostic metho d in the detection and staging of colorectal recurrence and differenti al diagnosis of pancreatic tumour versus chronic pancreatitis.