Clarence K.W. Wong, MD, FRCPC, Gastroenterologist and Clinical Lecturer, Division of Gastroenterology, University of Alberta; Consultant, Cross Cancer Institute, Alberta Cancer Board, Edmonton, AB.

Introduction
Gastrointestinal malignancies collectively account for the greatest number of cancer deaths in Canada.¹ This is particularly evident in the elderly population in which 90% of all new cancers are diagnosed in individuals over the age of 45.² Of these new cancers, one in five are gastrointestinal cancers. As these malignancies are often lethal, improved survival depends on preventive strategies to effectively detect and manage the associated precursor conditions. This paper will review the premalignant conditions associated with three common gastrointestinal cancers. Effective management of conditions leading to esophageal, gastric and colon cancers can greatly reduce the burden of disease among the geriatric population.

Esophageal Cancer
Cancers of the esophagus are lethal, with a death to case ratio of 1.11.¹ Although this estimate is high due to incomplete registration of new cases, it underscores the lack of effective treatment for this disease. Until recently, squamous cell carcinomas were the most common type of esophageal cancer. However, in the last few decades the incidence of esophageal adenocarcinomas has increased exponentially. It is likely that this increase is linked to a rise in incidence of its only known risk factor, Barrett's esophagus.