Introduction to cancer

Question 1

What is cancer

Answer 1

“A malignant growth or tumour resulting from an uncontrolled division of cells”
abnormal growth of cells caused by faults in the regulation of cell cycle. Damaged cells which should die through apoptosis survive resulting in a malignant growth/tumour resulting from an uncontrolled division of cells.

Question 2

What is a tumour

Answer 2

simply means swelling
usually refers to a benign/ malignant lesion

Question 3

What is a Bengign tumour

Answer 3

increase in cell number of normal and healthy cells.
mass of cells that grows slowly and remains localized- may not cause symptoms

Question 4

Symptoms of a benign tumour

Answer 4

• Pressure resulting from normal function like more hormone production affecting normal bodily function.
• Pressure on surrounding tissues
• Presure due to obstruction of ducts or passage ways
• pressure on skin if formed in a tight space like the skull

Question 5

what is a malignant tumour

Answer 5

increase in cell number of abnromal and unhealthy cells

Question 6

symptoms of a malignant tumour

Answer 6

Pressure, loss of function due to growth and invasion of surrounding tissues causing numbeness/ weakness and obstruction of vital structures like GI tract/ production of hromones or cytokines/ disruption of blood supply causing reduced blood flow and death of surrounding tissues. Metastasis in distant organs causing loss of function.
change in bowl habit, irregular bleeding, loss of weight, pain

Question 7

Features of a benign tumour

Answer 7

Slow growing
Usually encapsulated
Smooth surface
Cells are highly differentiated (resembling normal tissue of origin)
Cells are fairly uniform and resemble each other

Question 8

features of a malignant tumour

Answer 8

Rapid growth
Irregular tumour surface
No capsule
Tumour destroys the surrounding tissue
Usually causes death if not treated
Tumour cells are usually not as well differentiated

Question 9

features of benign cancer - blood vessels and DNA

Answer 9

• increased blood vessel formation:timulate the formation of new blood vessels to support their growth (angiogenesis)
• blood vessels in the tumour are well formed
• usually have no necrosis ( cell death due to injury. disease, low blood supply)
• does not metastasise
  -DNA content is usually normal
• karyotype is usually normal

Question 10

features of malignant cancer - blood vessels and DNA

Answer 10

• increased blood vessel formation
• blood vessels in the tumour are poorly formed
• usually has some necrosis
• can metastasise
• DNA content is usually abnormal
  -karyotype is usually abnormal

Question 11

What is a tumour? What are the forms ?

Answer 11

Means swelling - increase in size of an organ/area
-can be inflammation, a cyst or a cancer
-can be caused by neoplasia
-can be either benign or malignant
-cancer is always malignant

Question 12

What is neoplasia?

Answer 12

Neo = new
plasia = growth

Question 13

Dysplasia

Answer 13

Translates as bad growth
Shows as variation from normal cellular patterns - epithelium classified by structure and function is dependent on this structure

Question 14

Dysplasia - microscopic features

Answer 14

Pleomorphism (variation in size and shape)
Hyperchromatism(excessive pigmentation)
Presence of excessive mitotic figures - an unusual number of cells which are currently dividing
Also seen as a failure of maturation

Question 15

Reporting Dysplasia

Answer 15

Some degree of subjectivity
Often double reported - can progress to high grade?
Microscopic assessment of changes is key
Reported as low or high grade dysplasia

Question 16

Low grade dysplasia features (microscopic )

Answer 16

Enlarged, elongated, crowded nuclei
Shows features of inflammation
More likely to regress

Question 17

High grade Dysplasia

Answer 17

Pleomorphic, stacked nuclei
Shows features of carcinoma
More likely to progress

Question 18

Examples of cancer classifications

Answer 18

Carcinoma - Arises from an epithelium - 90% of cancers
Sarcoma- Arises from bone, muscle, cartilage or fat
Melanoma- Arises from melanocytes
Lymphoma - Arises from lymphocytes
Leukaemia - Arises from white blood cells

Question 19

Causes of cancer

Answer 19

Damage to cellular controls via UV raditaiton, Chemical damage or physical damage. This is caused by sun exposure, pesticides, smoking, poor diet, lack of exercise, infections and obesity.
Cancer is a disease of environment and lifestyle with genetic factors involved. Stress is a big factor but is not casuative
Persistent inflammation leads to cancer.

Question 20

Predisposing Factors

Answer 20

Age - Most cancers occur in those over 55 years of age
Contrast behaviour of childhood tumours- more aggressive and more likely to be fatal
Genetics
Family history
Familial adenomatous polyposis
Presents as early as teenage, multiple polyps that will become cancerous – removal of colon
BRCA1 & BRCA2 in breast and ovarian cancer
Predisposing pathologies
Ulcerative colitis
Crohn’s disease
Lichen sclerosis
Immunosupression
Environment

Question 21

Diagnosing Cancer. What type of samples are taken and why?

Answer 21

Sample - biopsy or cytology
dependent on type of cancer suspected, tumour location

biopsy: removal of small piece of tissue from suspected tumor/ abnormal area for microscopic examination. can be needle or incisional. entire tumour can be removed.
biopsy chosen if a solid tumour is acessible for sampling for more infromation about the cell morphology/ characteristics. useful in diagnosing and staging of cancer

Cytology: examination of individual cells from suspected tumour or lesion via fine-needle aspiration to extract cells or brush cytology.
Used when biopsy is difficult or risky or patients not suitable for surgery. can provide rapid diagnostic information about cellular characteristics of the tumour. used for lymph nodes, thyroid, liver, various bodily fluids ( pleural, Cerebospinal)

Question 22

Diagnosing cancer - What do we see in samples down the microscope?

Answer 22

Hyperplasia
Multiple nucleoli
Hyperchromatic nuclei
Increased nuclear / cytoplasmic ratio
Other microscopic features of tumours include:
-Pleomorphism - variation in size and shape of cells within the neoplasm.
-Abnormal mitoses - highly indicative of malignancy

Question 23

How is cancer further characterised?

Answer 23

Ki67 proliferation index