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
TNM Staging System
There are several types of staging methods.
•The ‘tumour, node, metastasis’ (TNM) system classifies cancer by:
•T (1–4): Size of primary tumour; e.g. 4 is largest.
•N (0–3): Degree of lymph node involvement.
•M (0–1): Metastasis (1 indicates metastasis).
•(X = cannot be assessed).
Cancer: Local Effects
A tumour with no function damages the ‘space’ it occupies.
• Tumours can compress blood vessels leading to necrosis of surrounding tissues. In larger tumours, it occurs within tumour (i.e. calcification -> on x-ray).
• Malignant cells do not adhere to each other — they metastasise.
• Pain is not usually an early symptom of cancer. If it occurs, it is caused by pressure or inflammation.
• Obstruction may occur in tubes or ducts in the body.
• Tissue ulceration / necrosis may produce infection (more likely with chemo / radiotherapy because of compromised immunity).
Cancer: Systemic Effects
- Weight loss and cachexia
- Anaemia
- Infection
- Para-neoplastic syndromes
Weight-loss and cachexia
- Cachexia is weight loss and muscle atrophy (hence fatigue and weakness).
- Cancer patients can still have a strong appetite.
Anaemia
This can occur due to malnutrition, chronic bleeding from an ulcerated tumour, bone marrow suppression.
Infection
Host resistance compromised, giving way to infections; e.g. pneumonia.
Para-neoplastic syndromes
- Symptoms that occur at site distant from a tumour or metastases.
- E.g. lung cancers may produce ACTH leading to Cushing’s syndrome (excess corticosteroids produced by lung tumour cells).
Metastasis
Metastasis describes the spread of a malignant tumour.
• Malignant tumours spread via blood or lymph and produce secondary tumours.
• Often first metastases appear in regional lymph nodes.
• Venous and lymphatic flow usually endangers mostly the lungs and liver.
• Cells in the secondary tumour are similar to the parent tumour.
• Common sites of metastasis include: Bone, liver, lungs and brain.
Cancer Presentation
Initially very few, vague symptoms in cancer: • Unexplained weight loss. • Anaemia and fatigue. • Night sweats. • Unusual bleeding or discharge (e.g. vaginal). • Persistent indigestion / heartburn. • Difficulty swallowing. • Change in bowel or bladder habits. • A change in appearance of a wart or mole. • Persistent cough or hoarseness. • A solid lump. • Swollen lymph nodes.
Diagnostic Tests
- BLOOD TESTS.
- TUMOUR MARKERS.
- IMAGING.
- BIOPSIES.
Diagnostic tests:
• Diagnostic tests enable detection of malignant growths.
• Testing also supports better monitoring of progress.
• No diagnostic test is 100% reliable and false positive or false negative results are possible.
Blood tests
- These include: haemoglobin, erythrocytes, leukocytes (leukaemia), platelets.
- Liver, thyroid, renal function tests.
Tumour Markers
- Substances (usually proteins) produced by tumours (malignant cells). Can be found in the blood, urine, stools or tissues.
- Some markers are found in non-cancerous conditions, whilst other tumour markers might indicate a malignancy.
- Tumour markers must be used within the context of the patient presentation and other clinical findings.
- Some tumour markers are more sensitive / more indicative of some types of cancer; e.g. CA-125 and ovarian cancer.
Tumour Markers: CEA
Carcinoembryonic antigen (CEA) is a glycoprotein that is present within normal mucosal cells, but is often undetectable in the blood after birth.
• CEA is a blood-borne marker.
• CEA can be elevated in certain types of cancer, especially colorectal cancer.
• CEA has a low sensitivity and specificity and so is used more for monitoring than screening or diagnosing (blood test).
• May also be elevated in ulcerative colitis, pancreatitis and liver cirrhosis.
Tumour Markers: PSA
Prostate specific antigen (PSA) is a protein produced by prostatic cells.
• PSA is normally present in small quantities in the serum (blood) of healthy men.
• May be elevated in the presence of prostate cancer and in other prostate disorders such as benign prostatic hyperplasia.
• PSA is used to assist in the diagnosis of prostate cancer, although it often produces false positives.
• PSA testing can be used to monitor tumour progression and metastasis (particularly post-treatment).
Tumout Markers: hCG
human chorionic gonadotropin:
• Males do not naturally produce β-hCG.
• Can test for cancer in some locations — testicles, pancreas, pituitary, placenta.
• Also elevated in pregnancy (should only be produced at this time).
Tumour Marker: M2-PK
- Not an organ-specific tumour marker, so it may be elevated in many tumour types.
- Increased stool levels are being investigated as a screening method for colorectal tumours and levels may be used for follow-up screenings in various other cancers.
Tumour Marker: CA-125
- CA-125 is a protein that may be elevated in many cases of ovarian cancer and tested in a blood test.
- CA-125 can be monitored to see whether treatment might be destroying the cancerous cells.
- Normal blood ranges are less than 35 U/mL.
Tumour Marker: 15-3
• CA 15-3 is a tumour marker that may be elevated in breast cancer patients in a blood test.
• CA 15-3 can be useful in monitoring metastatic breast cancer.
• Normal blood ranges are less than 30 U/mL.
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Imaging
- X-rays -> harmful (induce mutation).
- MRI: Magnetic resonance imaging.
- CT: Computed tomography.
- Radioisotopes.
Biopsies
- Fine needle, core or surgical biopsies.
- A small sample of tissue is removed and examined histologically.
- Malignant cells have an undifferentiated cell structure.
- Speculation that taking the biopsy may cause cancer cells to break off and spread.
Treatment
Basic conventional treatments: (combined or single).
• Surgery
• Chemotherapy
• Radiation
Curative
Treatment that is used in an attempt to resolve the malignancy.
Palliative
- Care that focuses on reducing symptom severity rather than ‘curing’. This is seen in late stages where symptomatic management and preventing complications is vital.
- Palliative care focuses on quality of life.
Surgery
Removal of the tumour, surrounding tissue and lymph nodes. Some examples include:
• MASTECTOMY: Removal of the breast.
• PROSTATECTOMY: Removal of the prostate gland with a very high rate of adverse effects!
• ORCHIECTOMY: Removal of the testes.
Radiotherapy
- Radiotherapy can be administered with curative or palliative intentions.
- Affects those cells which divide most rapidly (both cancer cells and healthy cells which divide regularly).
- Causes loss of reproduction and induces apoptosis.
Radiotherapy: Types
- There are three different types of radiotherapy:
- External beam radiation
- Internal beam radiation
- Systemic beam radiation
External Beam Radiation
Beams are generated from outside the patient.
Internal Beam Radiation
A higher dose of radiation released from within a body cavity.
Systemic Beam Radiation
Radioactive material enters the blood to reach cells all over the body (very toxic!).
Radiotherapy adverse effects
- Bone marrow depression (leading to aplastic anaemia with pancytopenia) immunocompromised.
- Inflammation / ulceration of skin exposed to beams.
- Hair loss and gut ulceration (diarrhoea and bleeding).
- Sterility.
- General fatigue / weakness. Fibrosis of tissue.
Support during radiation
- Exercise reduces the fatigue during radiation therapy.
- Adequate rest and relaxation is essential (reduces stress).
- Acupuncture, herbs, homeopathy; e.g. radiation burns: Calendula, Rad. brom. / Sol / Sulphur.
- Creams, gels and oils applied to skin irritation, etc.
Chemotherapy
Specific chemical agents that are destructive to malignant cells.
• Targets rapidly dividing cells (cannot distinguish between normal and cancer). Healthy cells that have high rate of growth -> adverse effects.
• It interferes with protein synthesis and DNA replication.
• Different drug combinations are chosen for different cancers.
Chemotherapy: Adverse effects
Often develops 7–14 days post treatment. • Bone marrow depression; (opportunistic infections, fatigue, bruising, etc.). • Diarrhoea, vomiting, nausea. • Hair loss. • Organ damage and cancer!
Other Cancer Drugs
HORMONES:
•Oestrogens or anti-androgen drugs for prostate cancer.
•Tamoxifen to block oestrogen receptors -> adverse effects (effectively induces menopause).
•Glucocorticoids (for example, in lymphomas).
BIOLOGIC RESPONSE MODIFIERS:
•Interferon
ANALGESICS:
•Opioid analgesics such as morphine (act on the CNS) can be given to assist with symptomatic management (common in palliative medicine).
Nutritional Therapy
- Phytonutrients (essential also in cancer prevention), high level of antioxidants, high fibre, whole plant foods, adequate protein and omega-3; support immunity; anti-inflammatory foods.
- Diet rich in fruit and vegetables (7–9+ portions).
- Anti-tumour substances; e.g. antioxidants, plant-based diet, folate (prevents DNA damage), beta glucans (e.g. mushrooms), amygdalin.
- Medicinal mushrooms (immunomodulators and adaptogenics); e.g. chaga, cordyceps, reishi, shiitake
Herbal Medicine
- There are numerous herbs that have been shown as effective in supporting cancer patients; for example:
- Chemo- and radiotherapy protective adaptogens.
- Anti-tumour adaptogens.
- Herbs protective against oxidative stress.
Other Complementary Treatments
- Acupuncture.
- Homeopathy.
- Other therapies; e.g. Ayurveda, TCM, reflexology.
Prognosis
A ‘cure’ for cancer is generally defined by orthodox medicine as a five-year survival without reoccurrence.
• It is essential to recognise that cancer reoccurrence after this period is common.
• In some cases, several periods of remission may occur before the cancer becomes terminal.
• Death rates vary for different types of cancer and are dependent on the individual.
• Some malignancies are more aggressive and metastasise more rapidly than others.
• Some cancers only present clinically once the disease is very advanced.
Types of Cancer
Carcinomas
Sarcomas
Leukaemias
Carcinomas
Cancers which form in epithelial tissue lining skin, mouth, nose, throat, respiratory tract, lung, breast, prostate, stomach, intestines.
Sarcomas
Cancers which develop in connective tissue
bone, cartilage, muscles, tendons.
Leukaemias
- Cancers which evolve in blood and bone marrow.
- Abnormal leukocytes produced travel throughout the bloodstream.
- They do NOT form solid tumours, but invade other cells.
