17. Oncology Flashcards
Oncology
Dealing with the study and treatment of cancer (malignant tumours)
Onocologist
A physician who practices oncology
Neoplasm
A mass of tissue that grows faster than normal in an uncoordinated manner
Tumour
Literally mean ‘swelling’ (Latin) but is now primarily used to describe a mass/growth of tissue. This growth can be either malignant or benign
A tumour no longer responds to normal growth factors, grwoing faster than normal in an uncoordinated manner
Cancer
Cancer is the second leading cause of death globally and is responsible for nine million deaths per year.
• The most common causes of cancer death in the world are: Lung, liver, colorectal, stomach and breast.
• Globally, the number of people with cancer is projected to double by 2030.
• More developed countries have higher cancer rates. This emphasises the link to environment, lifestyle, diet, medications and drugs.
Cancer Environments
Acidic environment
Anaerobic environment
Glucose rich
Acidid environment
Red meats Processed foods Dairy Sugar Salt Smoked Foods
Anaerobic environment
Lacking oxygen
Consider stress, breathing, diet, exercise
Glucose rich
Malignant cells are dependent on glucose for their own metabolism. These cells have many more glucose receptors on their membrane
Cell cycle
- Proteins are normally produced by cells which give it contact inhibition.
- Contact inhibition prevents cells dividing beyond the space available.
- Cancerous cells lose contact inhibition.
- Together with contact inhibition, cells have a programmed number of reproductive cycles.
Mutation
The change in the genetic information (change in DNA sequence / number).
Mutagen
An agent that changes the genetic information. Mutagens can be:
• Environmental hazards.
• Chemicals (environmental, household, drugs, vaccines).
• Radiation (x-rays, microwaves, mobile phones).
• Viruses.
• Inflammation.
• Defective immunity.
• Stress / emotional trauma.
Carcinogen
- A carcinogen is any cancer-causing agent.
* For example: Nitrosamines, heavy metals, asbestos, x-rays, UV-rays
Carcinogenesis
- Carcinogenesis is the process by which normal cells are transformed into cancer cells.
- Only 5–10% of cancers are attributed to inherited genetic defects, whilst the remaining 90–95% are attributed to the environment and lifestyle.
- Generally, causative factors can be difficult to establish because many cancers take many years to develop. Some tumours take 20–40 years.
Risk Factors
- Genetic factors (e.g. BRCA) / family history.
- Chronic inflammation — inflammatory bowel diseases, gastro-oesophageal reflux disease, gastritis, etc. Chronic inflammation promotes proliferation of cancer cells.
- Radiation — environmental, medical, microwaves, phones.
- Smoking — causes one mutation every 15 cigarettes.
- Drugs and cosmetics — (e.g. parabens).
- GIT dysfunction — liver (detoxifies substances), intestines (excrete body wastes, absorb nutrients and immune function).
- Vitamin D deficiency and thyroid disease.
- Chronic stress — suppresses the immune system.
- Sexual behaviour (e.g. cervical cancer, HIV, etc.)
- Compromised immunity.
- Excess alcohol (e.g. for mouth, oesophageal, breast and colorectal).
- Obesity; e.g. breast cancer in post-menopausal women (excess body fat changes hormone metabolism higher oestrogen drives oestrogen-positive tumours).
- Excessive exposure to sunlight.
- Metal toxins (i.e. aluminium. mercury).
- Medications e.g. immunosuppressants, HRT, antibiotics (altering flora and immunity).
- Vaccine ingredients e.g. aluminium, formaldehyde, mercury, human / animal DNA, etc.
Dietary Risk Factors
- Red meats (especially for colorectal, prostate, bladder, breast, gastric and pancreatic cancers). Higher risk if charcoal cooked / smoked and at high temperatures.
- Burnt food (produces ‘acrylamides’).
- Low fibre — high in phytochemicals and clears toxins and hormones such as oestrogen through the bowel.
- N-nitroso compounds (e.g. cured meats).
- Refined sugars — feed cancer cells and promote growth (and increase acidity).
- Dairy — pro-inflammatory and contains IGFs (insulin- like growth factors) that promote tumour growth.
- Table salt, pesticides and aspartame.
Cancer and Host Immunity
Chronic immunodeficiency can increase the risk for cancer.
• Cytotoxic T-lymphocytes, natural killer cells and macrophages are needed to destroy abnormal cells.
• HIV targets CD4 cells (T-helper cells and macrophages), which, therefore, compromises the host immune system.
• Even chronic stress, which would elevate cortisol levels, would suppress the immune system.
• A healthy, functioning immune system is essential to providing support against malignant cell development.
Benign Tumours
Benign tumours usually consist of differentiated cells which appear similar to normal cells so may be functional.
• Reproduce at a higher rate than normal.
• A benign tumour is very often encapsulated -> no metastasis.
• It grows very slowly and does not spread; systemic effects rarely seen.
• Not life-threatening but damage can result from compression of tissues (e.g. brain -> raised intracranial pressure).
Malignant Tumours
Usually made of undifferentiated, non-functional cells with varied shapes and sizes and large nuclei.
• The cells reproduce much faster than normal.
• Not encapsulated -> infiltrate other tissues (metastasise).
• Often systemic — can spread very quickly to other organs.
• Life-threatening due to tissue destruction and spread of tumour.
• Oncology is the study of malignant tumours.
Grades
Grading is the measure of the degree of cell differentiation / abnormality.
Grade 1
Tumour cells still similar to original. Cells are differentiated and specialised (i.e. benign tumour).
Grade 4
Tumour cells undifferentiated / many abnormal cells varying in size and shape.
Staging
Staging is the classification of malignant tumours according to the extent of the disease at the time of diagnosis.
• Staging helps to identify treatment approaches, disease progression and prognosis.
Stage 0
Pre-cancerous cells
Stage I
Cancer limited to tissue of origin
Stage II
Limited local spread of cancerous cells
Stage III
Extensive local and regional spread
Stage IV
Distant metastasis
