Behaviour of Tumours

Question 1

Describe what invasion means in terms of a malignant tumour

Answer 1

• Invades adjacent normal tissue
• Destroys normal tissue
• Local disease

Question 2

Describe what metastasis means in terms of a malignant tumour

Answer 2

• Spreads from site of origin to distant sites
• Forms new tumours in these areas
• Systemic disease

Question 3

What types of cancers are most likely to metastasise?

Answer 3

• 1/2 of all cancer patients
• Majority of lung cancer patients
• 1/3 of breast cancer patients
• Almost no basal cell carcinoma patients

Question 4

What are the characteristics of invasion?

Answer 4

• Increased motility
• Decreased adhesion
• Production of proteolytic enzymes
• Mechanical pressure

Question 5

What happens when a Cadherin mutates?

Answer 5

Mutation of E-Cadherin leads to loss of cell-cell adhesion and contact inhibition

Question 6

What happens when an Integrin mutates?

Answer 6

Changes in integrin expression lead to decreased cell-matrix adhesion

Question 7

What is the difference between epithelial cell connection and mesenchymal cell connection?

Answer 7

• E= tightly connected, polarised and tethered
• M= loosely connected, able to migrate
• In cancer epithelial cells gain mesenchymal properties allowing them to invade/migrate

Question 8

Name a proteolytic enzymes which degrades extracellular matrix. What does it degrade specifically?

Answer 8

• Matrix Metalloproteinases

- Collagen

Question 9

Name 3 proteolytic enzymes and what they degrade

Answer 9

• Interstitial Collagenases= Collagen types I, II, III
• Gelatinases=Collagen types IV, gelatin
• Stomolysins=Collagen type IV, proteoglycans

Question 10

How can Proteolytic enzymes aid in cancer formation?

Answer 10

• Increase in matrix Metalloproteinases
• Cancer favours ECM breakdown
• Decrease in tissue inhibitors of Metalloproteinases

Question 11

What is mechanical pressure?

Answer 11

• Uncontrolled proliferation forms mass
• Pressure occludes vessels
• Pressure atrophy
• Spread along lines of least resistance

Question 12

What are the routes of metastasis?

Answer 12

• Lymphatic = Distant or local lymph nodes
• Blood = Liver, lungs, bone, brain
• Transcoelomic = Across peritoneal, pleural, pericardial cavities or CSF
• Implantation = Spillage of tumour during biopsy/ surgery

Question 13

Give examples of patterns of metastasis

Answer 13

• Carcinomas= lymphatic spread
• Sarcomas= blood spread
• Bone metastases= lytic (lung) or sclerotic (prostate), breast, kidney, thyroid
• Transcoelomic= Ovarian
• Brain& adrenal= Lung

Question 14

What does staging mean?

Answer 14

How advanced is the tumour?

Has the cancer spread and if so what is the extent of the spread

Question 15

What does grading mean?

Answer 15

How aggressive is the tumour?

How different does it look from tissue of origin

Question 16

What are the stages of cancer progression?

Answer 16

1) Pre-invasive
2) Early tumour
3) Locally advanced
4) Metastases
5) Death

Question 17

What are tumours staged using?

Answer 17

TMN
T= tumour
M= metastases
N= nodes
Each organ has an individual TMN system

Question 18

Describe TMN staging

Answer 18

T= Size +/- extent of primary tumour
M= Presence and extent of distant metastases
N= Presence and number or lymph node metastases

Question 19

What are the T stages of TMN staging

Answer 19

Tis= in situ disease
T1= 7cm (invasion of fat/adjacent structures)

Question 20

What are the N and M stages of the TMN staging?

Answer 20

N0= no nodes
N1= Ipsilateral nodes
N2= > node involvement
M0= no distant metastases
M1= distant metastases

Question 21

What do stages 0-IV contain (as in TNM)

Answer 21

0= Tis
1= T1, N0, M0 = Surgery only
2= T1-2, N1 or T3 = Surgery & RT
3= T(any), N2 or T4= Surgery & chemo
4= T(any), N(any), M1 = chemo

Question 22

Describe Duke staging

Answer 22

-For Colorectal cancer
A= Invades into but not through bowel wall, >90% 5 year survival
B= Invades through bowel wall but no lymph metastases, 70% 5 year survival
C= Local lymph nodes involved 30% 5 survival
D= Distant metastases 5-10% 5 year survival