Lec 14- What is cancer

Question 1

Introduction

Answer 1

• The last 20 years has seen a better understanding of the causes and improved treatments of cancer
• There are over 200 forms of cancer- and probably a lot more than this at the genetic level
• Early detection technology has improved the prognosis of cancer patients
• Symptoms of cancer often initially misdiagnosed
• Approx 300,000 new cases diagnosed per year in UK
• 1 in 3 develop cancer, 1 in 4 deaths from cancer
• Early detection and improvements in therapy have improved prognosis- 15,600 to 12,300 per 100,000

Question 2

Cancer

Answer 2

• Cancer is a term used to describe a large group of diseases that are characterised by cellular malfunction
• Healthy cells are programmed to respond to their local environment- life and death signals continually received; without +ve signals most cells programmed to die
• Cancerous cells have lost this programming and therefore grow and replicate ‘out of control’
• Decreased requirement for signals and contact/anchor
• De-differentiate (loss of specific function)
• These cells are termed a neoplasm.

Question 3

Different types of cells

Answer 3

• Blood cells- erythrocytes, monocytes
• Muscle cells- smooth, striated, cardiac
• Nerve cells
• Bone cells
• Cartilage cells
• Liver cells

Question 4

Healthy cells

Answer 4

• Cells represent the basic functional unit of our existence. Carry out metabolism, reproduction, day to day functions
• Cells have specialized functions
• Most cells can grow and replicate
• Repair body organs
• The genetic material (DNA/RNA) and the immune system regulate this process

Question 5

Tumours- Benign

Answer 5

• Non-cancerous
• Enclosed in a fibrous shell or capsule
• Take up space- can interfere with surrounding tissues or vessels, impede the function of the body, look unpleasant
• May secrete excess hormones/other factors

Question 6

Tumours- malignant

Answer 6

• Cancerous
• Invades surrounding tissues
• Become uncontained- metastasis
• Loose function (de-differentiate)

Question 7

Types of cancer

Answer 7

• Carcinomas- epithelium derived
• Sarcomas- mesenchymal derived (Soft tissue)
• Leukemias- blood and bone marrow (haematopoietic)
• Lymphomas- lymphocytes (lymphoid tissue, immune system)
• Germ cell- testicle and ovary
• Blastoma- precursor cell, not terminally differentiated

Question 8

Describing cancer

Answer 8

• Staging of cancer
  
  • TNM: Tumour, lymph node, Metastasis
  • Staging 0-4
    
    • Stage 0= no evidence - non-invasive
    • Stage 1= small tumour with no spread to local LN
    • Stage 2= based on size or spread to local LN
    • Stage 3= based on size and spread to local or more distant LN
    • Stage 4= fully metastatic spread to distant parts of body

Question 9

An overview of cancer

Answer 9

• Cellular change/mutation theories
  
  • Spontaneous errors
  • External agents
  • Oncogenes
• Risks for cancer-lifestyle
  
  • Smoking among greatest
  • Nutritional/exercise

Question 10

Errors in DNA replication

Answer 10

Question 11

What causes cancer

Answer 11

• Biological factors
  
  • Genetic predisposition
  • Reproductive and hormonal risks
• Chemicals in foods- Na nitrate, C.botulism
• Viral factors- herpes related virus and human papillomavirus
• Medical factors
  
  • Diethylstibestrol (DES)
  • Chemotherapy
• Occupational and environmental factors
  
  • Asbestos, nickel, chromate
  • Radioactive substances
• Social and psychological factors- stress and negative emotion

Question 12

Risk factors (multi-factional)

Answer 12

• Genetic predisposition
• Exposure to cancer-causing agents
• Random cellular mutations
• Hormone exposure (i.e. oestrogen + breast cancer)
• Occupational and environment factors
• Social and psychological factors
• Chemicals in foods
• Viral (HPV, herpes) create an opportunistic environment
• Medical factors

Question 13

Factors believed to contribute to global causes of cancer

Answer 13

Question 14

Types of cancer- Breast cancer

Answer 14

• 1 in 8 women
• Risk increases with age
• Risk factors supported by research
• Prevention (self-exam and mammography)
• Treatment

Question 15

Types of cancer- Skin cancer

Answer 15

• 1.3 million cases of skin cancer
• Treatable: basal or squamous
• Virulent: malignant melanoma
• ABCD rule about melanoma

Question 16

Types of cancer- Colon and rectum cancer

Answer 16

• 3^rd most common in men and women
• 135,400 in 2001 diagnosed
• Warning signals, e.g. blood in the stool, rectal bleeding

Question 17

Types of cancer- prostate cancer

Answer 17

• Most common in males today
• 189,000 cases will be diagnosed
• Estimated 30,200 men will die

Question 18

Types of cancer- Pancreatic cancer

Answer 18

• Silent disease
• 29,700 cases in 2002
• Only 4% survive
• Contributors: inflammation, diabetes, high-fat diet

Question 19

Types of cancer- Testicular cancer

Answer 19

• Ages 17-34 at greatest risk
• Cause is unknown
• Undescended testicales present a great risk
• How and when should men examine there testicles

Question 20

Types of cancer- Ovarian cancer

Answer 20

• 4th leading cause of death in young women
• Enlargement of abdomen common sign
• Prevention: annual pelvic exams

Question 21

Types of cancer- Endometrium (uterine) cancer

Answer 21

• Pap test for early detection
• Risk: early onset of intercourse
• Warning abnormal bleading

Question 22

Types of cancer- Leukemia

Answer 22

• Cancer of blood-forming tissues
• Leads to the creation of immature white blood cells
• Symptoms: fatigue/paleness/weight loss
• Can be acute or chronic