cancer Flashcards
define a tumour
any abnormal swelling
define a neoplasm
a new lesion resulting from the abnormal growth of cells which persists after the initiating stimulus has been removed
list 6 key features of a neoplasm
- autonomous (not normally controlled, can grown on its own regardless of hormones)
- abnormal
- removing the stimulus won’t stop its growth (eg. stopping smoking won’t make it go away)
- new
- persistent
- made of neoplastic cells and stroma
what are the 3 types of neoplasm (behavioural classification)
bening
borderline eg. looks benign but behaves malignant
malignant
how do benign and malignant neoplasms differ in terms of their:
- invasiveness
benign - does not invade the BM
malignant - does invade the BM and has the potential to spread around the body (metastases)
how do benign and malignant neoplasms differ in terms of their:
- growth
benign - Grows upwards and outwards (exophytic) and has a slower growth rate (and slow mitotic activity)
malignant - Grows inwards (endophytic) and rapidly (high mitotic activity)
how do benign and malignant neoplasms differ in terms of their:
- resemblance to normal tissue
benign - often look similar to normal tissue
malignant - Variable resemblance to normal tissue . The less it resembles it, the worse the prognosis (higher grade neoplasm)
how do benign and malignant neoplasms differ in terms of their:
- confinement to a limited area
benign - often well circumscribed or encapsulated
malignant - poorly circumscribed, poorly defined border therefore difficult to remove it all
how do benign and malignant neoplasms differ in terms of their:
- necrosis and ulceration likelihood
benign - rare (because grows slowly)
malignant - common (because grows rapidly, outgrows its blood supply)
how do benign and malignant neoplasms differ in terms of their:
- nuclei
benign - normal
malignant - darker than normal (hyper-chromatic) and vary in shape (pleomorphic)
- risk of causing morbidity and mortality
both can
benign - exert pressure on adjacent structures and obstruct flow. can produce hormones eg. hyperthyroidism and can become malignant
malignant - destroy adjacent tissue, metastases, obstruct flow, produce hormones, have paraneoplastic effects
both can cause anxiety
histogenic classification of neoplasms:
what are the 3 broad types of cells the body is made up of and can have cancers ?
Epithelial cells
Connective tissues
Lymphoid
histological grading :
what are the 3 different grades a tumour can be ?
Grade 1 – Well differentiated (most closely resembles parent tissue)
Grade 2 – Moderately differentiated
Grade 3 – Poorly differentiated
how do you name a benign epithelial tumour?
prefix - cell type of origin
suffix - papilloma or adenoma
eg. squamous cell papilloma , colonic adenoma
what is the difference between a papilloma and adenoma?
Papilloma: benign tumour of non-glandular epithelium.
Adenoma: benign tumour of glandular epithelium,
how do you name a malignant epithelial tumour?
prefix - cell type of origin + Adeno if glandular
suffix - carcinoma
eg. urothelial carcinoma
define a carcinoma
define a sarcoma
carcinoma = malignant tumour of epithelial cells
sarcoma= Malignant connective tissue neoplasm.
how do you name a benign connective tissue tumour?
prefix - cell origin
suffix - oma
how do you name a malignant connective tissue tumour?
prefix - cell origin
suffix - sarcoma
naming connective tissue tumours:
- name a benign and malignant tumour of adipocytes
benign - lipoma
malignant - liposarcoma
naming connective tissue tumours:
- name a benign and malignant tumour of striated muscle
benign - rhabdomyoma
malignant - Rhabdomyosarcoma
naming connective tissue tumours:
- name a benign and malignant tumour of smooth muscle
benign - Leiomyoma
malignant - Leiomyosarcoma
naming connective tissue tumours:
- name a benign and malignant tumour of cartilage
benign - chondroma
malignant - chondrosarcoma
naming connective tissue tumours:
- name a benign and malignant tumour of bone
benign - osteoma
malignant - osteosarcoma
naming connective tissue tumours:
- name a benign and malignant tumour of blood vessels
bengin - angioma
malignant - angiosarcoma
what is staging?
further classification of neoplasms
Measures level of tumour spread throughout body
Example: TNM (Tumour, Node, Metastasis) staging
what is it called when the cell type of origin of the tumour is unknown?
anaplastic tumour
how do you name a malignant tumour of lymphoid tissue?
lymphomas
how do you name a malignant tumour of haemopoietic tissue?
leukaemia
list some exceptions to the naming of tumour rules:
- there are some -omas that are not neoplasms eg. granulomas
- not all malignant tumours are carcinomas/sarcomas eg. melanoma (malignant neoplasm of melanocytes)
- some are eponymously named eg. burkitts lymphoma
- teratomas - neoplasms contains tissues from all 3 embryological layers
- mixed tumours
- carcinosarcomas - both epithelial and stromal element are malignant
what is a carcinoma in situ?
a malignant epithelial neoplasm that has not yet invaded through the original basement membrane
BM is intact
can treat by removal
what is an invasive carcinoma?
a carcinoma that has breached the basement membrane – it can now spread elsewhere
what is a Micro-invasive carcinoma:
carcinoma has breached the basement membrane but hasn’t invaded very far away from the original carcinoma
Pragmatic term to use when it has invaded but not very far
what is the difference between invasion and metastasis ?
invasion is the initial spreading of a malignant neoplasm to nearby tissues
metastasis is the process by which a malignant tumour spreads from its primary site to produce secondary tumours at distant sites. It happens after invasion, breaking off from primary tumour to spread further and establish secondary tumours
what are the 8 main steps in the metastatic cascade?
Detachment
Invasion
Intravasation (getting into vessels or lymphs to spread by)
Evasion of host defences (within vessels, avoids WBCs)
Arrest
Extravasation - leaving vessel
Growth at metastatic site
Vascularisation
what are some factors that aid the metastatic cascade ?
Abnormal cell motility
uses proteases to get through collagen of BMs
Use aggregation with platelets, shedding of surface antigens and adhesion to other tumour cells in order to evade host immune response
Growth factors to help growth at new site
what is angiogenesis? when does it happen?
formation of new blood vessels
After Metastatic cascade, the tumour is at a new metastatic site
It starts to grow
Once the tumour reaches 1 mm in diameter, it begins to grow its own blood vessels (angiogenesis).
what are the different routes of metastasis that can be taken?
- Haematogenous - spread via the blood stream
- lymphatic - spread via lymph channels
- Trans-coelomic – spread through the pericardial and peritoneal cavities
which tumours commonly metastasis to the lungs?
any common cancer
which tumours commonly metastasis to the liver?
colon,
stomach,
pancreas,
carcinoid tumours of intestine
which tumours commonly metastasis to the bone?
Breast
Lung
Thyroid
Kidney
Prostate
(BLT KP)
define Carcinogenesis
= the transformation of normal cells to neoplastic cells (mostly malignant) through permanent genetic alterations or mutations.
is a multistep process
define Oncogenesis
Oncogenesis = formation of a tumour which could be benign or malignant
what’s the difference between carcinogenic and oncogenic ?
Carcinogenic = causes cancer (malignant)
Oncogenic = tumour (benign or malignant) causing
what are the 5 classes of carcinogens?
- Chemical
- Viral
- Ionising and non-ionising radiation
- Biological agents (Hormones, parasites, Mycotoxins)
- Miscellaneous (eg. Asbestos and arsenic )
give an example of a chemical carcinogen and the cancer(s) it can cause?
exposure to polycyclic aromatic hydrocarbons (in smoke, in car pollution) increases likelihood of lung and skin cancer
give an example of a viral carcinogen and the cancer(s) it can cause?
Hepatitis B Virus associated with Hepatocellular carcinoma
give an example of a non-ionising radiation carcinogen and the cancer(s) it can cause?
Exposure to UVA or UVB increases the risk of developing all types of skin cancer (BCC, melanoma and SCC)
give an example of a ionising radiation carcinogen and the cancer(s) it can cause?
Lung cancer in uranium miners
give an example of a hormonal carcinogen and the cancer(s) it can cause?
Increase oestrogen increases chance of mammary/endometrial cancer
give an example of a parasitic carcinogen and the cancer(s) it can cause?
Schistosoma
increased risk of squamous cell carcinoma of the bladder
give an example of an occupation that has been associated with increased cancer risk
aniline dye and rubber industries
increased risk of Bladder cancer
give an example of an environment that has been associated with an increased risk of cancer
Hepatocellular carcinoma is common in areas with mycotoxins
host factors:
- how does race/ethnicity affect risk of cancer?
Decreased skin cancer in black people (melanin)
Increased oral cancer in India, SE Asia (reverse smoking - when they smoke from the lit end of the cigarette)
host factors:
- how does diet and lifestyle affect risk of cancer?
Excess alcohol and Obesity increases risk
Unprotected sex increases risk of HPV-related cancer (cervix, penis, oropharyngeal)
Exercise reduces risk
host factors:
- how do constitutional factors affect risk of cancer?
Inherited disposition
Age – incidence increases with age (longer been exposed to environment, longer you have had to acquire the mutation)
Gender
host factors:
- how do pre malignant conditions affect risk of cancer?
Identifiable local abnormality associated with increased risk of malignancy at that site e.g. colonic polyps, undescended testis, cervical dysplasia
So if you have a polyp, there is a chance it could become cancer
host factors:
- how does transplacental exposure affect risk of cancer?
Transmitted via placenta
Morning sickness medication (diethylstiboestrol) cross the placenta, caused increase in vaginal carcomas in unborn child
give 2 examples of inherited predispositions to colorectal cancer?
Hereditary nonpolyposis colorectal cancer (HNPCC) and Familial adenomatous polyposis (FAP)
what kind of prevention is cancer screening?
secondary prevention
which cancers are screened for in the UK?
breast
cervical
bowel
how is breast cancer screened for?
every three years for all women aged 50 to 70 with a mammogram
how is cervical cancer screened for?
All women between the ages of 25 and 64 are eligible for a free cervical screening test every three to five years with a Liquid based cytology
how is bowel cancer screened for?
every two years to all men and women aged 60 to 69 with a faecal occult blood (FOB) test kit
Why can excision be used as a cure for basal cell carcinoma?
Because BCC doesn’t metastasise.
Suggest a treatment that could be used for leukemia?
Chemotherapy. Leukemia is systemic, it circulates all around the body, therefore excision can’t be used.
Give an example of a carcinoma that can spread to the axillary lymph nodes.
Breast carcinomas.
Why is adjuvant therapy often used in the treatment of carcinomas?
Micrometastes are possible even if a tumour is excised and so adjuvant therapy is given to suppress secondary tumour formation.
Give an advantage and a disadvantage of conventional chemotherapy.
- Advantage: works well for treatment against fast dividing tumours e.g. lymphomas.
- Disadvantage: it is non selective for tumour cells, normal cells are hit too; this results in bad side effects such as diarrhoea and hair loss.
What kind of carcinomas would targeted chemotherapy be most effective against?
Slower dividing tumours e.g. lung, colon and breast.
What is the theory behind targeted chemotherapy?
It exploits the differences between cancer cells and normal cells; this means it is more effective and has less side effects
What kind of drugs can be used in targeted chemotherapy?
Monoclonal antibodies (MAB) and small molecular inhibitors (SMI).
What is required for a tumour to invade through a basement membrane?
- Proteases.
- Cell motility.
What is required for a tumour to enter the blood stream (intravasation)?
- Collagenases.
- Cell motility.
What is required for a tumour to exit the blood stream (extravasation)?
- Adhesion receptors.
- Collagenases.
- Cell motility.
Give 2 promoters of tumour angiogenesis.
- Vascular endothelial growth factors.
- Fibroblast growth factors.
Give 3 inhibitors of tumour angiogenesis.
- Angiostatin.
- Endostatin.
- Vasculostatin.
What 3 mechanisms do tumour cells use to evade host immune defence in the blood?
- Platelet aggregation.
- Adhesion to other tumour cells.
- They shed surface antigens so as to ‘distract’ lymphocytes.
What percentage of cancer risk is due to environmental factors?
85% environmental, 15% genetic.
Chemical carcinogens: what types of cancer do aromatic amines cause?
Bladder cancer.
Chemical carcinogens: what type of cancer do nitrosamines cause?
Gut cancer.
Describe neoplastic cells.
Neoplastic cells are derived from nucleated cells. They’re usually monoclonal and their growth is related to the parent cell.
Describe the stroma of a neoplasm.
Connective tissue composed of fibroblasts and collagen; it is very dense. There is a lot of mechanical support and blood vessels provide nutrition for the neoplastic cells.
Why does necrosis often occur in the centre of a neoplasm?
The neoplasm grows quickly and outgrows its vascular supply.
What are the two ways in which neoplasms can be classified?
- Behavioural classification.
- Histogenetic classification.
