Introduction 30-40% of all cancers arise from the epithelial lining of the aerodigestive tract. 51% & 38% of cancer deaths of men and women are from lung and GI tract. These cancers are discovered late, are also aggressive and resistant to chemo- and radiation therapy.

Lung cancer In men, the incidence is slightly lower than that of prostate cancer but mortality is 3 times higher. In women, the incidence is less than half that of breast cancer but mortality is slightly higher.

Etiology Tobacco smoking Uranium Radon

Types Non-small cell carcinoma –Squamous cell carcinoma –Adenocarcinoma –Large cell undifferentiated –Others Small cell carcinoma –Aggressive –Chemotherapy- sensitive –Neuroendocrine differentiation

Esophageal cancer Mostly squamous cell carcinoma. Adenocarcinoma is less common. 1-2% of all cancer deaths in USA Occurs in adults (>50 yo) Male:Female = 3:1

Risk factors Retarded passage of food Long-standing esophagitis Alcohol consumption Tobacco abuse Loss of tumour suppressor gene (p53) Others

Squamous cell carcinoma Pathogenesis Mild Moderate Severe

Esophageal adenocarcinoma

Gastric cancer Worldwide, high incidence in Japan Declining incidence & mortality 3% of all cancer deaths in USA Five year survival <10%

Risk factors Chronic atrophic gastritis Dietary factors Chronic gastritis (Helicobacter pylori)

Pancreatic cancer Almost equal incidence rate as gastric cancer One of the most lethal of all human cancers 5 year survival is <5% Most cases occur in the head of pancreas

Colorectal cancer 98% of large bowel cancers Almost always in an adenoma Familial or sporadic Worldwide distribution, high in NA Peak incidence years of age

Adenoma-carcinoma sequence

Risk factors Low vegetable diet High content of carbohydrates, fat and protein Decrease protective micronutrients (vitamins A, C & E) Familial

Types Sporadic (the majority) Hereditary/familial –Familial adenomatosis polyposis (FAP) syndrome –Hereditary non-familial polyposis