Oncology Flashcards
Oncology
The study and treatment of cancer (malignant tumours)
Onco = tumour, -ology = study of
Oncologist
A physician who practises oncology
Neoplasm
A mass of tissue that grows faster than normal in an uncoordinated manner
Neo = new, -plasia = growth
Tumour
Latin for ‘swelling’– used to describe a mass / growth of tissue. Can be either malignant or benign.
A tumour no longer responds to normal growth factors, growing faster than normal and in an uncoordinated manner
Tumour = swelling
Cancer statistics
The leading cause of death globally (nearly 10 million deaths per year).
Most common causes of cancer death in the world are; lung, colorectal, liver, stomach, breast
By 2040 – global burden is expected to grow to 27.5 million new cases and 16.3 deaths
More developed countries have higher cancer rates – links to environment, lifestyle, diet, medications and drugs
Cells and division; Mitosis and meiosis
Mitosis and meiosis are the processes of cellular growth and reproduction. Mitosis is the growth and repair of somatic cells
Meiosis is the process that produces sex cells (gametes)
Cells and division in cancer
All cells are differentiated and specialised. Cells are organised in a tissue and fulfil the tissue’s function
If cells become disorganised and grown in an uncontrolled manner, their function is lost. Cell architecture is key to observe in suspected neoplastic growth.
Cancer Biology; Genetics – Genetic mutations
Cancer occurs as a result of genetic mutations.
It is the result of an underlying cause.
The causes of cancer promote the mutations of multiple genes – it is essential to explore the interaction of the patient’s genes with the environment.
Cancer Biology; Genetics – Tumour suppression genes and oncogenes and angiotenesis
Tumour suppression genes (‘off switch’) become inactivated.
New genes called oncogenes (‘on switch’) are formed that cause over production of growth factors and increase cell division (divide at an uncontrolled & rapid pace)
Malignant cells can only grow 1-2mm3 without a blood supply, so undergo angiotenesis
Cancer Biology; Pro cancer environment
It is paramount to recognise the environment that cancer cells thrive in. The prime environment is:
1; Acidic
2; Anaerobic
3. Glucose rich
It is essential to consider the environment that we bathe our genes in. Genes load the gun, the environment is the trigger
Cancer Biology; Acidic Environment
Acidic environment; Red meats (sulphur = sulphuric acid), processed foods, dairy, sugar, salt and smoked foods add to the acidity of the body
Can assess pH – markers in saliva / urine
Cancer Biology; Anaerobic environment
Anaerobic environment; ‘Lacking Oxygen’. Consider stress (contracting muscles – O2), breathing (lack of 02), diet, exercise (sedentary – lactic acid)
Cancer Biology; Glucose rich environment
Glucose rich environment; Malignant cells are dependent on glucose for their own metabolism. These cells have many more glucose receptors on their membrane. Refined sugars are especially harmful – feed tumours.
Cell Cycle - contact inhibition
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
Cancer Causes: Carcinogen
A carcinogen is any cancer causing agent;
E.g. Nitrosamines, heavy metals, asbestos, x-rays, UV-rays
Cancer Causes; 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
90-95% of cancers 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
Include:
* Genetic factors (e.g. BRCA) / family history
* Chronic inflammation, e.g. inflammatory bowel diseases, gastro-oesophageal reflux disease, gastritis, etc. Chronic inflammation promotes proliferation of cancer cells
* Radiation, e.g. environmental, medical, microwaves, phones
* Smoking, e.g. causes one mutation every 15 cigarettes
* Drugs and cosmetics, e.g. parabens
* GIT dysfunction, e.g. 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. immunosuppressant’s, HRT, antibiotics (altering flora and immunity)
* Vaccine ingredients e.g. aluminium, formaldehyde, mercury, human/animal DNA, etc
Dietary Risk factors
- Red meats (esp. 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 photochemicals 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 of 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
The measure of the degree of cell differentiation / abnormality
* Grade 1; Tumour cells still similar to original. Cells are differentiated and specialized (i.e. benign tumour)
* Grade 4; Tumour cells undifferentiated / many abnormal cells varying in size and shape
Staging
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
Basic staging:
* 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 (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
* Tissues ulceration / necrosis may produce infection (more likely with chemotherapy / radiotherapy because of comprised immunity)
Cancer: Systemic Effects; Weight loss and Cachexia
Weight loss and Cachexia: Cachexia is weight loss and muscle atrophy (hence fatigue and weakness)
Cancer patients can still have a strong appetite
Cancer: Systemic Effects; Anaemia
Anaemia; This can occur due to the malnutrition, chronic bleeding from an ulcerated tumour, bone marrow suppression
Cancer: Systemic Effects; Infection
Infection; Host resistance compromised, giving way to infections; e.g. pneumonia
Cancer: Systemic Effects; Para-neoplastic syndromes
Para-neoplastic syndromes; Symptoms that occur at a 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
The spread of a malignant tumour.
* Malignant tumours spread via blood or lymph and produce secondary tumours.
* Often first metastasis 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
Metastasis = ‘change of state’
Cancer Presentation
Initially very few, vague symptoms in cancer (the symptoms ultimately depend on the location of the malignancy);
* Unexplained weight loss
* Anaemia and fatigue (without obvious cause)
* 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;
Diagnostic tests:
* Enable detection of malignant growths
* Testing supports better monitoring or progress
* No diagnostic test is 100% reliable - false positives or false negatives results are possible.
Tests include:
1. Blood tests
2. Tumour markers
3. Imaging
4. Biopsies
Diagnostic tests; Blood tests
Blood tests include;
* Haemoglobin, erythrocytes, leukocytes (leukemia), platelets
* Liver, thyroid, renal function tests
Diagnostic tests; Tumour markers
Tumour markers;
* Substances (usually proteins) produced by tumours (malignant cells). Can be found in the blood, urine, stool 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 / indicative of some types of cancer e.g. CA-125 & ovarian cancer
Diagnostic tests; 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.
* Can be elevated in the certain types of cancer, especially colorectal cancer.
* 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.
Diagnostic tests; 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
* Is used to assist in the diagnosis of prostate cancer, although it often produces false positives
* Testing can be used to monitor tumour progression and metastasis (particularly post-treatment)
Diagnostic tests; Tumour markers – hCG
Human Chorionic Gonadotropin (hGC)
* Males do not naturally produce b-hCG
* Can test for cancer in some locations – testicles, pancreas, pituitary, placenta
* Also elevated in pregnancy (should only be produced at this time)
Diagnostic tests; Tumour markers - M2-PK
Not an organ-specific tumour marker so 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 carious other cancers
Diagnostic tests; Tumour markers – 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
Diagnostic tests; Tumour markers – CA 15-3
CA 15-3 is a tumour marker that may be elevated in breast cancer patients in a blood test
* It can be used in monitoring metastatic breast cancer
* Normal blood ranges are less than 30 U/mL
Diagnostic tests; Imaging
- X-rays = picks up mass of tissue / anatomical growth with calcification (harmful - induce mutation)
- MRI – magnetic resonance imaging (soft tissues / in more detail)
- CT- Computed tomography (similar to X-ray taking images of multiple locations across the body – harmful effects)
- Radioisotopes (compounds e.g. such as swallowing to see the pathway)
Diagnostic tests; Biopsies
- Fine needle, core or surgical biopsies
- A small sample of tissue is removed and examined histological
- Malignant cells have an undifferentiated cell structure
- Speculation that taking the biopsy may cause cancer cells to break off and spread
Treatment - types
Basic conventional Treatments: (combined or single)
* Surgery – harmful with possible side effects
* Chemotherapy – extremely toxic and harmful
* Radiation – extremely harmful
N/B – Conventional treatment is aimed at removing / suppressing and not treating the cause – cancers often return
Treatment; Surgery
Removal of the tumour, surrounding tissue and lymph nodes. Some examples inc;
* Mastectomy; removal of the breast
* Prostatectomy; Removal of the prostate gland (with a very high rate of side effects)
* Orchiectomy; Removal of the testes
Treatment; Radiotherapy
Radiotherapy can be administered with curative or palliative intentions. Affects cells which divide rapidly (both cancer cells & healthy cells which divide regularly)
Causes loss of reproduction and induces apoptosis (cell death)
Treatment; Radiotherapy side effects
Radiotherapy adverse effects:
* Bone marrow depression (leading to aplastic anaemia with pancytopenia (deficiency of RBC, WBC and platelets)) = immunocompromised.
* Inflammation / ulceration of skin exposed to beams
* Hair loss and gut ulceration (diarrhoea and bleeding)
* Sterility
* General fatigue / weakness.
. Fibrosis of tissue.
Treatment; Radiotherapy side effects support
Support during radiation:
* Exercise – reduces the fatigue
* Adequate rest and relaxtion (reduce stress
* Acupuncture, herbs, homeopathy e.g. radiation burns; calendula, Rad Brom / Sol / Sulphur (together)
* Creams, gels and oils applied to skin irritation etc.
Treatment; Chemotherapy
Specific chemical agents that are destructive to malignant cells
* Targets rapidly dividing cells (cannot distinguish between normal and cancer). Healthy cells that have a high rate of growth = side effects
* They interfere with protein synthesis and DNA replication
* Different drug combinations are chosen for different cancers
Treatment; Chemotherapy side effects
Adverse effects; Often develops 7-14 days post treatment
* Bone marrow depression = Anaemia, thrombocytopenia, leukopenia etc. (opportunistic infections, fatigue, bruising, etc)
* Diarrhoea, vomiting, nausea
* Hair loss
* Organ damage and cancer
Treatment; Other drugs
Hormones:
* Oestrogens or anti-androgen drugs for prostate cancer
* Tamoxifen to block oestrogen receptors = adverse effects (effectively induces menopause)
* Glucocorticoids (e.g. in lymphomas)
Biologic Response Modifiers:
* Interferons
Analgesics:
* Opioid analgesics such as morphine (act on the CNS) can be given to assist with symptomatic management (common in palliative medicine)
Treatment; Complimentary
Complimentary therapists are not allowed to ‘treat’ cancer, they can support the journey of medical treatment and help alleviate / reduce adverse effects
Cancer prevention is important - It can take decades for a tumour to develop
Treatment; Complimentary – nutritional therapy
Nutritional Therapy;
* Phytonutrients (essential also in cancer prevention), high level of antioxidants (patients will have lots of free radicals), high fibre, whole plant foods, adequate protein and omega-3; support immunity – anti-inflammatory foods
* Diet rich in fruits and veg (7-9+ portions)
* Anti-tumour substances; e.g. antioxidants, plant-based diet, folate (prevents DNA damage), beta glucans – immune modulating and anti-cancer properties (e.g. mushrooms), amygdalin (aka b17) - cause cell suicide through cyanide formation in cancerous cells (apricot kernels)
Treatment; Complimentary – Medicinal mushrooms
Medicinal mushrooms (immunomodulators and adaptogenics), e.g;
* Chaga
* Cordyceps
* Reishi
* Shiitake
Treatment; Complimentary – Herbal Medicine
Herbal medicine; Numerous herbs have been shown as effective in supporting cancer patients; e.g.
* Chemo and radiotherapy protective adaptogens
* Anti-tumour adaptogens
Herbs protective against oxidative stress
Treatment; Complimentary – Other
- Acupuncture (energy / life force within body)
- 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
* 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 dependant on the individual
* Some malignancies are more aggressive and metastasise more rapidly than others
* Some cancers only present clinically once the disease is very advances
Types of Cancer
Cancers can be broadly cateforised based on the cell types:
* Carcinomas
* Sarcomas
* Leukaemias
Types of Cancer; Carcinomas
Carcinomas; Cancers which form in epithelial tissues lining skin, mouth, nose, throat, respiratory tract, lung, breast, prostate, stomach, intestines
Types of Cancer; Sarcomas
Sarcomas; Cancers which develop in connective tissue = bone, cartilage, muscles, tendons
Types of Cancer; Leukaemias
Leukaemias; Cancers which involve in blood and bone marrow.
Abnormal leukocytes produced travel throughout the blood strea.
They do NOT form solid tumours, but invade other cells
Treatment - Outcomes / approaches
Treatment approaches are;
1. Curative; Treatment that is used in an attempt to resolve the malignancy
2. Palliative; Care that focuses on reducing symptoms 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
N/B – Conventional treatment is aimed at removing / suppressing and not treating the cause – cancers often return
Treatment; radiotherapy types
There are three different types;
1. External bean radiation; beams are generated from outside the patimet
2. Internal beam radiation (AKA bracki therapy); a higher dose of radiation released from within a body cavity
3. Systemic beam radiation; radioactive material enters the blood to reach cells all over the body (very toxic)
