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

Chronic Reflux Gastric

adenocarcinoma

Intestinal metaplasia (Barrett's esophagus)

Dysplasia

Direct extension

Primary 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 60-70 years of age

Adenoma-carcinoma sequence

Normal Mucosa

Mucosa at risk

Adenoma

Adenocarcinoma

Invasive adenocarcinoma

First hit

Second hit

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