17. Oncology Flashcards
What is a neoplasm?
A mass of tissue that grows faster than normal in an uncoordinated manner
What is a tumour?
A mass or growth of tissue
Can be benign or malignant
What are the most common causes of cancer death in the world?
Lung Liver Colorectal Stomach Breast
Which types of countries have higher cancer rates?
Developed countries
What type of cell division do cancer cells undergo?
Mitosis
What architecture do normal cells have?
Start off differentiated and specialised
Organised in the tissue and fulfil a particular function
What architecture do cancer cells have?
Not differentiated
Grow in an uncontrolled manner
Becoming irregular and disorganised
Specialised function is lost
How does cancer come about?
Through genetic mutations
Result of an underlying cause
What are tumour suppression genes?
They tell a cell when to stop dividing
What happens to tumour suppression genes (TSG) during cancer cell growth?
TSG becomes deactivated
New genes called oncogenes are formed
What do oncogenes do?
Cause the overproduction of growth factors and increase cell division at uncontrolled/rapid pace
What is angiogenesis?
Growth of new blood vessels
Why do malignant cells undergo angiogenesis?
As they can only grow 1-2mm without a blood supply
What is the prime environment for cancer cells to thrive in?
Acidic
Anaerobic
Glucose rich
What is contact inhibition?
Prevents cells dividing beyond the space available
Do cancer cells have contact inhibition?
No
What is mutation?
Change in genetic sequence
What is a mutagen?
An agent that changes the genetic sequence
Examples of mutagens
Chemicals Radiation Viruses Inflammation (chronic) Stress/emotional trauma Defective immunity Environmental hazards
What is a carcinogen?
A cancer-causing agent
What is carcinogenesis?
The transformation of normal, healthy cells into cancer cells
Examples of carcinogens
Heavy metals
Asbestos
X-rays
UV rays
What percentages of cancers are attributed to genetics vs environmental factors?
5-10% genetics
90-95% environment/lifestyle
How long can tumours take to develop?
20-40 years
What are risk factors for cancer?
Genetics Chronic inflammation Chronic stress Smoking Radiation Excess alcohol Obesity Excessive exposure to sunlight Compromised immunity Metal toxins Medications Vaccine ingredients Drugs/cosmetics GIT dysfunction Sexual behaviour Vit D deficiency/thyroid disease
What are dietary risk factors?
Red meats Burnt food Low fibre Refined sugars Dairy Table salt Pesticides Aspartame N-nitroso compounds (cured meats)
How can chronic immunodeficiency increase the risk of cancer?
Cytotoxic T-cells, NK cells, macrophages are needed to destroy abnormal cells. However..
HIV targets CD4 cells, compromising the immune system
How can chronic stress suppress the immune system?
By elevating cortisol levels
What is the architecture for benign tumours?
Differentiated cells
Appear similar to normal cells
May be functional
How do benign tumour cells reproduce?
At a higher rate than normal
How do benign tumour cells grow?
Very slowly
Doesn’t spread (encapsulated - no metastasis)
Are benign tumours life-threatening?
No but damage can result from compression of tissues
What is the architecture for malignant tumours?
Undifferentiated cells
Non functional
Varied shapes/sizes
Large nuclei
How do malignant tumour cells reproduce?
Much faster than normal
How do malignant tumour cells grow?
Rapidly
Not encapsulated so they metastasise
Can spread quickly to other organs
Are malignant tumours life-threatening?
Yes due to tissue destruction and spread
What is grading?
The measure of degree of cell differentiation/abnormality
What are grade 1 tumours?
Similar to original cells
Differentiated and specialised
What are grade 4 tumours?
Undifferentiated
Abnormal cells varying in size and shape
What is staging?
Classification of malignant tumours according to size and spread of the tumour
What are the benefits of staging?
Helps to identify treatment approaches, disease progression and prognosis
What is stage 0 cancer?
Pre-cancerous cells
What is stage 1 cancer?
Cancer limited to tissue of origin
What is stage 2 cancer?
Limited local spread of cancerous cells
What is stage 3 cancer?
Extensive local and regional spread
What is stage 4 cancer?
Distant metastasis