Flashcards in Growth disorders 4 - Biology of cancer Deck (15)
Describe the aetiology of neoplasms.
Caused by 2 or more of the following factors:
- Genetic (most common)
- Chemical (polycyclic aromatic hydrocarbons)
- Microbial organisms
- Chronic diseases (e.g. chronic ulcers)
- Immune system disorders
What factors predispose an individual to neoplasms?
Combination of genetic and non-genetic factors.
1. Autosomal dominant inherited cancer syndromes
e.g. childhood retinoblastoma
2. Defective DNA repair syndromes and resulting DNA instability
e.g. Lynch syndrome/hereditary nonpolyposis colorectal cancer
3. Familial cancers
including breast, colon and ovary
2. Pre-cancerous conditions including non-neoplastic (solar keratosis of the skin) and neoplastic (benign neoplasms)
3. Geographical factors
Some countries have higher rates of certain cancers
e.g. Aus and NZ --> skin cancers
4. Carcinogenic agents
Chemical (polycyclic aromatic hydrocarbons)
Radiation (UV, ionising radiation)
Oncogenic viruses / other microbes (HPV and cervical cancer)
When do cancer mutations occur?
- During cell division
- Random event
- Stimulation from external agents
What kind of mutation do most cancers arise from?
Somatic mutations. Some cancers are caused by germline mutations.
What are the general effects of all neoplasms?
- Local pressure effects
- Abnormal functional activity (e.g. hormone synthesis)
- Obstruction (vessels, tubes, ducts)
- Rupture of blood vessels causing haemorrhage/infarction
- Specific effects depend on the behaviour of the neoplasm (is it benign or malignant?)
How does cancer spread/metastasise? What is a key indicator of metastatic cancer vs in situ?
Tumour cells can spread through the circulation.
A metastatic cancer is indicated by multiple masses, for example on the liver, vs one single mass.
List 3 facts about the clinical burden of cancer?
1. Cancer is a leading cause of death
2. Cancer death rate has been declining in the last few years
3. The most significant risk factor for cancer overall is age - over 2/3 of all cancer cases occur in people >65y
List the leading causes of cancer deaths in WA
Unknown (advanced metastasis)
Unknown (advanced metastasis)
Lung cancer is leading cause of cancer deaths
What is the five year survival rate for:
1. Lung cancer
2. Pancreatic cancer
1. Lung cancer = 15%
2. Pancreatic cancer = 3%
Describe TNM cancer staging
- TNM staging
- T: tumour (size, extent of spread)
- N: nodal status (number, groups, size)
- M: metastasis
- SITE DEPENDENT
A colorectal cancer is T4. What does this tell you?
The cancer has spread through the wall of the intestine and has reached another organ.
What are the clinical stages of cancer?
Stage I, II, III, IV (different to pathological e.g. TNM staging)
What is the difference between tumour staging between colorectal cancer and lung cancer?
Colorectal: T stage depends on the depth of invasion.
Lung: T stage depends on the size of the tumour and the organs invaded
i.e. TNM staging is site dependent!
What is the scheme used for cancer staging?