Pancreatic cancer: an overview of epidemiology, clinical presentation, and diagnosis.

Pancreatic cancer remains a challenge to researchers and investigators alike. Although the incidence of this neoplasm is increasing alarmingly, epidemiologic studies have provided few clues to genetic, behavioral, or environmental factors involved in its etiopathogenesis. Pancreatic cancer is highly lethal; diagnosis is rarely achieved while the tumor is at a localized, surgically resectable stage. It is possible that the early stages of pancreatic cancer are truly asymptomatic, and no effective screening method is yet available. In contrast, the presumptive diagnosis of advanced pancreatic cancer can nowadays be achieved with high probability in most patients by newly developed techniques. Comparative studies of currently available diagnostic tests have provided guidance in the selection of the best tests and the optimal sequence of investigation. Major research efforts are now being directed toward obtaining, without laparotomy, both evidence of nonresectability (staging) and histologic proof of neoplasia to avoid expensive, debilitating exploration in patients in whom cure or meaningful palliation cannot realistically be expected.