Pancreatic adenocarcinoma pathology: changing "landscape".

Pancreatic cancer is a devastating disease. At time of diagnosis the disease is usually advanced and only a minority of patients are eligible for surgical resection. The overall 5-year survival is 6%. However, survival of patients with early stage pancreatic cancer is significantly better. To improve the prognosis of patients with pancreatic cancer, it is essential to diagnose and treat pancreatic cancer in the earliest stage. Prevention of pancreatic cancer by treating noninvasive precursor lesions just before they invade tissues can potentially lead to even better outcomes. Pancreatic carcinogenesis results from a stepwise progression in which accumulating genetic alterations drive neoplastic progression in well-defined precursor lesions, ultimately giving rise to an invasive adenocarcinoma. A thorough understanding of the genetic changes that drive pancreatic carcinogenesis can lead to identification of biomarkers for early detection and targets for therapy. Recent next-generation sequencing (NGS) studies have shed new light on our understanding of the natural history of pancreatic cancer and the precursor lesions that give rise to these cancers. Importantly, there is a significant window of opportunity for early detection and treatment between the first genetic alteration in a cell in the pancreas and development of full-blown pancreatic cancer. The current views on the pathology and genetics of pancreatic carcinogenesis that evolved from studies of pancreatic cancer and its precursor lesions are discussed in this review.