Cancer and Neoplasia Flashcards
What is a tumour?
Any abnormal swelling - this includes inflammation, neoplasms, hypertrophy and hyperplasia
What is a neoplasm?
A lesion resulting from the autonomous abnormal growth of cells, which persists after the initiating stimulus has been removed.
What percentage of UK deaths can be attributed to neoplasia?
20%
What does a neoplasm consist of?
Neoplastic cells and stroma
Give 3 characteristics of neoplastic cells
- Derived from nucleated cells (usually monoclonal)
- Have a growth pattern related to the parent cell
- Have synthetic activity related to the parent cell (e.g. collagen, mucin, keratin, hormones)
What is the stroma of a neoplasm and what is its role?
The stroma supports the neoplasm; it consists of a connective tissue framework providing support and nutrition and its growth is supported by the neoplasm.
How large can a neoplasm grow without recruiting a blood supply?
About 2mm
Why does central necrosis sometimes occur in large vascularised tumours?
The tumour outgrows its blood supply and the cells in the centre die off as they are too far from the blood supply.
What are the two methods of classification used when classifying neoplasms?
Behavioural - e.g. benign/malignant/borderline
Histogenetic - cell of origin/what tissue is present
Give 7 characteristics of benign neoplasms
- Localised
- Non-invasive
- Slow growth rate
- Low mitotic activity
- Close resemblance to normal tissue
- Circumscribed/encapsulated
- Necrosis and ulceration are rare
Give 4 ways in which benign neoplasms can cause morbidity and mortality
- Putting pressure on adjacent structures and obstructing hollow structures
- Over-production of hormones - benign neoplasms can retain synthetic properties but are autonomous and therefore unregulated
- Transformation to malignant neoplasm
- Anxiety
Give 10 characteristics of malignant neoplasms
- Invasive
- Metastatic (may not have actually spread, but will have the potential to do so)
- Rapid growth rate
- High mitotic activity
- Variable resemblance to normal tissue
- Poorly defined/irregular border due to invasion of surrounding normal tissues –> margin between neoplasm and surrounding tissue unclear
- Hyperchromatic nuclei
- Necrosis and ulceration common
- “Crab-like” cut surface
Give 6 ways in which malignant neoplasms caused morbidity and mortality
- Destruction of adjacent tissue
- Metastases
- Blood loss from ulcers
- Obstruction of flow
- Hormone production
- Anxiety and pain (although cancer is usually advanced by the time pain is felt)
What is a papilloma?
A benign tumour of non-glandular, non-secretory epithelium. Prefixed with cell type of origin.
What is an adenoma?
A benign tumour of glandular/secretory epithelium. Prefixed with cell type of origin.
What is a carcinoma?
A malignant neoplasm of epithelial cells
What is a sarcoma?
A malignant neoplasm of connective tissue
What is an anaplastic tumour?
A tumour where the cell type of origin is unknown
What is carcinogenesis?
The transformation of normal cells to malignant neoplastic cells through permanent genetic alterations/mutations.
What is oncogenesis?
The transformation of normal cells to benign or malignant neoplastic cells
What does ‘carcinogenic’ mean?
Cancer causing
What does ‘oncogenic’ mean?
Tumour causing
What is a mutagen?
An agent that acts on DNA
Approximately what percentage of cancer risk is due to environmental factors?
85%
How was it discovered that hepatitis causes liver cancer?
High incidence of liver cancer was noted in areas with a high incidence of hepatitis B and C.
What is thought to be the reason behind the high incidence of oesophageal cancer in Turkey?
Food/drink being too hot, resulting in repeated thermal injury to the oesophagus, leading to cancer.
In which industries has there been a high incidence of bladder cancer among workers?
Aniline dye and rubber industries
Roughly how many deaths per year in the UK are caused by lung cancer?
About 35,000
How did Kent micronite filters manage to make smoking even more dangerous?
They contained asbestos
Why was there an increased incidence of scrotal cancer in male chimney sweeps?
Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic. Chimney sweeps used to carry a rag to wipe themselves down with, which was kept in the pocket, in close proximity to the scrotum.
Thorotrast is a colloidal suspension of thorium used as a radiographic contrast medium from 1930-1950. How did it cause cancer?
Thorium is irreversibly ingested by phagocytes and has a long half-life. E.g. if it is ingested by Kupffer cells, it can turn the liver radioactive.
Why did the Chernobyl disaster of 1986 cause a massively increased incidence of cancer in Ukrainian children?
Radioactive iodine was released into the atmosphere; iodine is used to synthesise thyroxine so radioactive iodine was being taken up into their thyroids.
Give two reasons why animal experimentation may not always be relevant to human experience.
- Animals may metabolise agents differently to humans, so agents that cause cancer in animals may not cause cancer in humans and vice versa.
- The laboratory environment that the animals are in is vastly different to the normal human environment.
Give 4 classes of carcinogens
- Chemical
- Viral
- Ionising/non-ionising radiation
- Hormones/parasites/mycotoxins