Invasion And Metastasis

Question 1

Carcinoma in situ defintion

Answer 1

A malignant epithelial neoplasm that has not yet invaded through the original basement membrane
- only applies to epithelial neoplasm
- may progress to invasive disease
- basement membrane is intact
- screening may allow detection and treatment before development

Question 2

Invasive carcinoma defintion

Answer 2

A carcinoma that has breached the basement membrane - it can now spread else where

Question 3

Micro-invasive carcinoma

Answer 3

Has breached the basement membrane but hasn’t invaded very far away from the original carcinoma

Question 4

What is invasion of a neoplasm?

Answer 4

• The defining feature of a malignant neoplasm
• Enables the neoplastic cells to spread directly through tissue and gain access to blood vessels and lymphatic channels
• It is dependant upon decreased cellular adhesion, abnormal cellular motility and the production of enzymes with a lytic effect on the surrounding tissues

Question 5

What is metastasis of a neoplasm?

Answer 5

• Process by which a malignant tumour spreads from its primary site to produce secondary tumours at distant sites
• May occur via blood vessels, lymphatics, across body cavities, along nerves or as a result of direct implantation of neoplastic cells during a surgical procedure

Question 6

Metastatic cascade process

Answer 6

Detachment
Invasion
- invade through the basement membrane
Intravasation
- collagenases, cell motility
Evasion of host defences
- aggregation with platelets
- shedding of surface antigens
- adhesion to other tumour cells
Arrest
Extravasation
- adhesion receptors
- collagenases
- cell motility
Vascularisation

Question 7

How does a metastatic neoplasia grow?

Answer 7

Growth at metastatic site using autocrine growth factors. Once the tumour reaches 1mm in diameter they begin to grow their own blood vessels (angiogenesis)

Question 8

Angiogenesis promotors

Answer 8

Vascular endothelial growth factors
Basic fibroblast growth facts

Question 9

Angiogenesis inhibitors

Answer 9

Angiostatin
Endo statin
Vasculostatin

Question 10

Routes of metastasis

Answer 10

Invade the arterial side if it grows large enough and breaks off
Haematogenous - by the blood stream - forms secondary tumours in organs perfused by blood that has drained from a tumour
Lymphatic - lymph channels - form secondary tumours in the regional lymph nodes
Trans-coelomic - pericardial and peritoneal cavities where this invariably results in a neoplastic effusion

Question 11

Tumours which more commonly metastasise to the lung are…

Answer 11

sarcomas and any common cancers

Question 12

Tumours which more commonly metastasise to the liver are…

Answer 12

Colon
Stomach
Pancreas
Carcinoid tumours of intestine

Question 13

Tumours which moe commonly metastasise to bone are…

Answer 13

Prostate
Breast
Thyroid
Lung
Kidney