tailieunhanh - Carcinoma of the Esophagus - part 2

Nhiều người trong số các yếu tố môi trường liên quan với một tỷ lệ cao của SCC thực quản liên quan đến hoàn cảnh kinh tế xã hội nghèo. Một chế độ ăn phong phú trong thực phẩm bảo quản và muối và ít trái cây tươi và rau quả, thiếu hụt vitamin và khoáng chất, và hiệu ứng nhiệt của thức ăn nóng | 4 S. S. Mudan and . Kang Etiology Squamous cell carcinoma Many of the environmental factors associated with a high incidence of SCC of the esophagus relate to poor socioeconomic circumstances. A diet rich in preserved and pickled foods and low in fresh fruit and vegetables vitamin and mineral deficiencies and a thermal effect of hot food and beverages have all been implicated. Alcohol intake and smoking are also strongly associated with an increased risk of SCC of the esophagus 28 29 30 31 . The risk is thought to be dose related and the genetic changes brought about by chronic exposure to causative agents lead to a progression through epithelial dysplasia and carcinoma in situ to invasive cancer 32 . After several years of cessation of exposure to irritant factors such as smoking and alcohol risk is substantially reduced 33 . Conditions such as caustic ingestion and achalasia of the cardia which are associated with chronic mucosal inflammation also predispose to SCC of the esophagus. Adenocarcinoma The recent and rapid escalation in incidence of esophageal adenocarcinoma would seem to suggest a mostly environmental rather than genetic effect. While a number of factors including race obesity use of esophageal sphincter-relaxing drugs smoking and alcohol consumption have all been incriminated as possible etiological factors in esophageal adenocarcinoma 34 35 36 37 38 many cohort studies have pointed strongly to gastroesophageal reflux and Barrett s disease Barrett s esophagus as a causative factor 39 40 . There is a strong dose-response relationship between previous gastroesophageal reflux symptoms and esophageal adenocarcinoma but the relationship to cardia cancer is weaker 40 . Wu et al. demonstrated a threefold increase in esophageal cancer and a doubling in cardia cancer with reflux symptoms 41 . The relationship between adenocarcinoma of the lower esophagus and adenocarcinoma of the cardia is less clear. Siewert et al. have separated adenocarcinoma .