Upper Gastrointestinal Tract Surgery
Patients with a history of surgical procedures for peptic ulcer disease appear to be at an increased risk for pancreatic cancer. The physiologic basis for this apparent risk is unknown, but in an experimental rat system, chronic duodenogastric reflux produced sustained hypergastrinemia and promoted pancreatic carcinogenesis. Other researchers have suggested that the increased risk of pancreatic cancer following peptic ulcer surgery may result from the increased formation of N-nitroso compounds by nitrate-reducing bacteria that proliferate in the relatively achlorhydric stomach.
Cholecystectomy has also been associated with an increased risk of pancreatic cancer. This association is controversial, however, and not all series have supported the claim that cholecystectomy increases risk. The possibility that prior cholecystectomy can influence pancreatic carcinogenesis is supported by observations that CCK, which circulates at higher levels after cholecystectomy, is important in experimental pancreatic carcinogenesis and can stimulate the growth of experimental pancreatic tumors.