Cancers of the gastrointestinal system

This chapter discusses all the tumours arising from the digestive tract and its associated organs such as the liver and gall bladder. The chapter covers epidemiological and aetiological factors and links to these changes in recent years in the frequency of each type of tumour, which often relates to lifestyle changes such as frequency of smoking, patterns of alcohol use, consumption of various foods, obesity, and various infective agents. The contribution of genetic factors and hereditary diseases is discussed for each tumour type. The appropriateness of screening programmes is considered. Clinical presentations are described and the investigations required for diagnosis (with imaging and molecular marker measurement) and staging, which, for most tumours, is according to the Union for International Cancer Control (UICC) system. The management, and the timing and use of combinations of surgery, radiotherapy, chemotherapy, and other systemic treatments, whether given alone, concomitantly, or sequentially, are included for localized, advanced, and metastatic disease in each anatomical area. Special techniques such as liver transplantation, various ablative procedures, and the use of brachytherapy are discussed where relevant. Ways of palliating incurable disease are given. Outcomes and prognosis vary considerably between tumour types and show differing patterns of change over time. For example, there has been an improvement in the outcomes of treatment for colorectal cancers but little improvement yet overall in the cure rates for cancers of the oesophagus.