Carcinogenesis 3 tumours on the move

Question 1

What is metastasis

Answer 1

The process where malignant tumours spread from primary tumour to form secondary tumours at distant sites

Question 2

WHat does carcinomatosis mean

Answer 2

Extensive metastatic carcinoma

Question 3

What sequence do malignat tumours follow to metastasise (describe it)

Answer 3

Detatchment of tumour cell from neighbors,
Invade connective tissues to reach lymphatics and blood vessels

Penetrate basement membrane of vessels to reach lumen

Evade host defence mechanisms (NK cells, T lymphocytes)

Adherence to endothelium as remote location

Extraversion of cells from vessel lumen to tissue

Survuval and growth in new environment

Question 4

What is the seed and soil hypothesis

Answer 4

metastasis depends on cross talk between selected cancer cells (seeds) and specific organ microenvironments (soil)

Question 5

What are the three routes of metastasis

Answer 5

Lymphatic
Haematogenous (blood)
Transcoelomic (across cavities)

Question 6

What happens during lymphatic metastasis

Answer 6

Tumour cells travel through afferent lymphatics to enter lymph node, enlarging and firming.
Tumour cells may cause adjacent lymph nodes to fuse, interrupting lymphatic flow

Question 7

Why are veins more easily invaded by metastases than arteries

Answer 7

Thinner walls and veins transport blood away from organs.

Question 8

Where do tumour cells stop with regards to haematogenous transport

Answer 8

The first capillary bed they meet

Question 9

What are the 5 cancers especially suceptible from haematogenous metastasis to bone?

Answer 9

Lung, kidney, thyroid, prostate and breast

Question 10

What is transcoelomic metastasis?

Answer 10

Metastasis to the peritoneal, pleural and pericardial cavities

Question 11

What cancers cause ascites, and what is it

Answer 11

Any abdominal tumour (especially ovarian) and it is abnormal fluid buildup in abdomen.

Cytological analysis can detect the cancer as it contains the malignant cells

Question 12

How are tumours recognised by the immune system and destroyed (assuming all goes well)

Answer 12

Tumour antigens presented on cell surface by MHC1 molecules which are recognised by CD8+ cytotoxic T cells

The antigens can be productos of mutated genes or overexpressed proteins

Question 13

Can immunosupression increase cancer risk

Answer 13

yes

Question 14

How do tumours avoid destruction by immune system

Answer 14

Selecting antigen negative clones, losing MHC molecules, or expressing transforming growth factor beta or PD1 ligands by tumour cells

Question 15

What is tumour staging

Answer 15

Referst to tumour spread, local and systemic. We use TNM system

Question 16

Wow does the NNM system of grading work

Answer 16

T means primary tumour, fuffixed by a number denoting tumour size or local anatomical extent (varies with organ)

N means lymph node status, suffixed by a number denoting number of (groups) lymph nodes containing metastases

M means anatomical extent of distant metastases

Question 17

According to TNM staging, what does Tis mean

Answer 17

Carcinoma in situ

Question 18

What is the relationship between cancer stage and patient survival rate

Answer 18

Inversely proportional

Question 19

What are the local effects of tumours

Answer 19

Destruction, displacement, compresssion

Think of compression on nerve plexus as well

Question 20

Can some tumours still produce hormones

Answer 20

yes, if they are well differentiated

Question 21

What is a paraneoplastic syndrome

Answer 21

Results from inappropriate secretion of a hormone by a tumour, which does not normally secrete the hormone

Question 22

Name some metabolic effects of cancer

Answer 22

Cachexia/weakness/weight loss despite nutrition

Warburg effect (no oxidation, glycolysis takes over, is why PET scans work)

Neuropathy and myopathy,

Venous thrombosis (especially pancreatic carconoma)

Glomerular injury

Question 23

Why is risk increased if a tumour obstructs a bronchus

Answer 23

Secretions may not be able to pass, predisposing to pneumonia

Question 24

How can metastatic canvcer of bone lead to death

Answer 24

Hypercalcaemia, renal failure, cardiac arrythmia

Pathological fracture leads to spinal cord compression

Question 25

How can a metastatic tumour of the liver cause death

Answer 25

electrolyte abnormalities

Question 26

How can tumour invasion affect blood vessels

Answer 26

Can cause haemhorrage and can block major veins

Question 27

What can brain tumours lead to

Answer 27

raised intercranial pressure, intra tumoural haemmhorage