Mechanisms of invasion and metastasis Flashcards
Modes of spread
Invasion: local spread
Metastasis: lymphatic spread
Metastasis: haematogenous spread
Metastasis: transcoelomic spread
Invasion: local spread
Path of least resistance
Tissue destruction
Perineural spread
Metastasis: lymphatic vessels
Invasion of vessels: embolism or permeation
Spread to draining lymph nodes
Metastasis: haematogenous spread
Invasion - mainly veins Organs -liver -lung -bone -brain
Metastasis: transcoelomic spread
Spread across serous cavities
-e.g. abdominal cavity
Mechanisms of spread
Tumour cells interact with cells and molecules in local environment Tumour cells gain new abilities -motility is enhanced -alter adhesion molecules make poor basement membrane >protease production or reduce inhibitors -alter ECM 'Metastatic cascade'
Pathway leading to metastasis
- Primary tumour formation
- Local invasion
- Intravasation
- Survival in circulation
- Arrest at distant organ site
- Extravasation
- Micrometastasis formation
- Metastatic colonisation
- Clinically detectable macroscopic metastases
Patterns of spread
Carcinomas -lymphatic -blood (often later) Sarcomas -blood (lymphatic spread rare) Predictable patterns of spread -lung to local nodes, liver, bone and brain -tongue to neck nodes, later lung and spine
Effects of tumour spread
Pressure and obstruction Destruction Haemorrhage Infection Pain Anaemia Starvation and cachexia
Non-metastatic effects (sometimes called paraneoplastic syndrome)
Often caused by biochemical substances released by tumour cells, e.g. TNKα
- fever, anorexia and weight loss/ cachexia
- endocrine syndromes: Cushings syndrome, metabolic effects e.g. hypocalcaemia
- neurological problems e.g. neuropathy
- haematological syndromes e.g. erythrocytosis
Grading of tumours
Histological assessment
Often related to differentiation
-the more differentiated, often the less aggressive
Linked to prognosis
Various methods
-numerical grades (1, 2, 3 etc.)
-low, intermediate, high (more likely to die of a low grade tumour)
Can we predict how tumours will behave?
Grading of tumours
Staging of tumours
Staging of tumours
Clinical extent of tumour
TNM system (tumour nodes [regional] and metastases [distant])
Specific staging systems for tissue/ tumour
-lower stage means more chance of survival
Diagnosis of cancer
Biopsy [main]
Cytology (FNA)
Imaging - CT and MR scanning
Molecular analysis
Treatment
Surgery Radiotherapy Chemotherapy Biological (immune) therapy Supportive care
