Cancer Flashcards
How do you name different types of cancer ?
What these prefixes mean ?
adeno chondro erythro hemangio hepato lipo lympho melano myelo myo osteo
What do these suffixes mean ?
- oma
- carcinoma
- sarcoma
- blastoma
Suffix Meaning
- oma benign tumour
- carcinoma epithelial cancer
- sarcoma mesenchymal cancer
- blastoma primitive cell cancer
adeno- gland chondro- cartilage erythro- red blood cell hemangio- blood vessels hepato- liver lipo- fat lympho- lymphocyte melano- pigment cell myelo- bone marrow myo- muscle osteo- bone
What is cancer ?
How does it happen ?
Unregulated cell growth - loss ability to control cell growth & replication——————> form a malignant tumor (can spread to other tissues and invade tissues. )
Mechanisms of cancer
0 CDK
CDK - cyclin dependant kinases - involved in cell regulation :
o too little - cell does not progress.
o too much - unregulated proliferation of cells.
0 Mutations
- cause cell to converted into cancerous cell by 2 mechanisms :
o activation of oncogenes (mutations of proteo-oncogenes- which regulate cell cycle ) e.g RAS , MYC gene
causes call to bypass checkpints and growth becomes unregulated.
- mutation in the RAS gene - produces RAS protein which are already activated ———————> constant intacellular phosphorylation of proteins & activation of transcription factor ——————-> overproduction of cyclins & CDK
MYC gene - makes proteins for cell growth , survival & activity. (Mutation ————> more of this———– cell becomes cancerous )
o Deactivation of tumour suppressor gene.
(p53 , APC , BRCA 1 & 2 )
e.g activation of p53 - not able to put cell into arrest , die or be repaired so cells grow unregulated.
What is the normal role of RAS gene in cell growth ?
Growth factor receptor ——————–growth factor binds to receptor ———————–> stimulated Growth factor receptor activates RAS protein on membrane ————————-> stimulates cascade of intracellular phosphorylation of other proteins which activates transcription factor. ——————————————> activated transcription factor hoes to gene and makes proteins fr cell growth e.g CDK AND CYCLINS.
What is the function of tumor suppression genes ?
Damaged DNA ———————-> production of P53 transcription factor ————————-> make proteins for cell arrest (e.g p21 - inhibits CDK and cyclins - cell cycle does not progress) & cell repair (so when cell is arrested cell is repaired ) % apoptosis ( if cell cant be repaired has to die. )
Characteristics of cancer cells ?
Anaplasia - loss of differentiation & organisation.
Autonomy - independent of cell cycle control.
normal —> dysplasia (normal cells undergo transformation by mutations , carcinogens , infection etc )——————> neoplasia ( abnormal cells form tumour - cancerous cells stack on top of each other (not normal ) - blood vessels start to form supplying new tumour (ANGIOGENSIS )————————————— > Invasive neoplasia – ( tumour continues to grow & cells divide & extensive BV supplying it ————> Tumour starts to penetrates through basement membrane into BV and cancerous cells enter blood and spread throughout body.
Types of lung cancer Lung cancer ?
2 Types
0 Small cell carcinoma
- aggressive - 2/3rd present with metastasis.
- primarily develops in older adult smokers.
- tend to occur close to hilium of lungs
- poor prognosis
- Linked to paraneoplastic syndrome (this cancer involves neuroendocrine cells which produce hormones ( should not be able to ) . )
0 Non - small cell carcinoma
- 85 % of lung cancers
e.g
o adenocarcinoma -(- most common non small cell - tend to occur (TTO) in peripheral lung tissue
)
o squamous cell carcinoma
(- 2nd most common
- TTO near bronchus - can cause obstruction of the airways.
- involves columnar cuboid epithelial cells lining bronchus converted into squamous cancerous cells ))
o Large cell carcinoma
- rapidly grow
- proximal or peripheral lung tissue. )
Common symptoms of Lung cancer ?
o Cough - airway obstruction ————-> intiates cough reflex ( so present with cough & dyspnoea )
o Weight loss
o Dyspnoea
o Chest pain
o Haemoptysis - angiogensis - New BC are leaky and prone to rupture
There can be blood involvement e,g :
- Anaemia ( fatigue & dyspnoea ) - leukocytosis - thrombocytosis - hypercoagulable disorders
Medistinal involvement of lung cancer ?
Pancoast tumor ( tumor at the apex of the lung ) -
- non small cell
- can compress brachial plexus – should arm pain , weakness , atrophy on the same side )
- can cause horner’s syndrome - damage to sympathetic nerve pathway from hypothamulus to face via upper spinal cord near carotid artery (CA)(causes by lesions to head a neck e.g tumor (pancoast or neuroblastoma ) ,surgery, dissection of CA ,
o Dropping eyelid
o contacted pupil
o dryness - lack of sweating on same side as affected eye
( unilateral )
0 Pleural effusion
0 Pericardial effusion
0 SVC blocked - Vena cava syndrome .
Lung cancer metastasis ?
spreads from lung ——————–> to heart———-. pumps tumor / cancer cells either to : brain , upper limbs or down to abdomen area.
Common sites
- Brain
- Liver
- bone
- adrenal gland.
What is the paraneoplastic syndrome ?
group of disorders triggered by abnormal immune response to a cancerous tumour——————> causes collateral damage to nervous system
- they occur at sites distant or tumour or its metastasis
e.g
ectopic cushing syndrome ——–> NE cells release ATCH —————> stimulate adrenal glands to release Cortisol
- neuroendocrine (NE) cells release ADH—————–> water rentention
& Parathyroid like substance ————————-> cause bone breakdown and release of CA ———-> Hypercalcemia
Hypertrophic pulmonary osteoarthropathy (HPOA) – group of symptoms :
o Clubbing - swelling of ends of fingers
o Spoon shaped nails
o Inflammation , swelling and pain in hands , fingers , knees and joints.
- peritonitis - inflammation of periosteum ( band of tissue surrounding bone )
- can happen in variety of conditions but when link to cancer considered a PN syndrome - most common in lung cancer.
Investigations of lung cancer ?
Chest x ray - 1 st - helps rule out differential diagnosis . - what you may see: o pulmonary opacity o pleural effusion o lung collaspe o hilum enlargement o rib bone lesions
CT scan - further assessment -detemine stage & management of cancer
sputum cytology - detect cancerous cells in sputum.
investigations to consider
- lung biopsy - Bronchoscopy and sample is taken.
- Thorocentesis - fluid sampled.
Difference between treatment of non small cell and small cell carcinoma ?
Small cell carcinoma - most present with metastasis - so surgery will be effective , Chemo -first line vs non small cell - Surgery first line for less advance stages.
Stages of cancer ?
5 stages
Stage 0 - cancer is in situ - hasn’t spread
Stage 1 - cancer no longer spread , but still not spread
Stage 2 - Cancer grown . not spread
Stage 3- larger & may have spread to surrounding tissue & lymph nodes
Stage 4 - Spread to secondary organ - metastatic.
TMN - Tumour T0- no tumour TIS - carcinoma in situ T1 , 2, 3, 4 - size & extent N - nodal status - NO - no nodular maliglancy N1, N2,N3 - increasing number of lymph node involved M - Metastasis M0 - no metastasis M1 . M2 - location of metastasis
What is colorectal / bowel cancer ?
Cancer that occurs in colon or rectum
- 3rd most common cancer
RISK FACTORS
- rare below age 40.
0family history link
- FAP - familal adenomatous Polyposis
- HNPCC - Hereditary nonpolyposis colorectal cancer / lynch syndrome (inherited)
- personal history of colon cancer
- history of inflammatory conditions of colon e.g IBD (UC & CD)
SYMPTOMS
0 Diarrhoea,
0constipation (sometimes referred to as ‘change of bowel habit’),
0 rectal bleeding
0 loss of weight
0 abdominal pain.
- may present with anaemia, particularly iron-deficiency
- Can be misdiagnosed as non -maligant conditions e.g IBD.
- right sided tumours typically present at a more advanced stage with symptoms of weight loss and anaemia (mostly asymptmatic apart from these so are diagnosed later allowing them to grow )
whereas left sided tumours ( mostly in - descending-sigmoid area) often present with rectal bleeding, change in bowel habit, and tenesmus ( cramping rectal pain - feel like you need to go to the toilet even though you dont.
rectal location - deep red blood on surface of stools
- deep bright red blood indicates bleeding is in rectum or low in colon
- darker maroon blood indicates bleeding higher up in colon.
When to refer for suspected colorectal cancer?
referral (for an appointment within 2 weeks) for colorectal cancer if:
0 They are aged 40 years and over with:
- unexplained weight loss
- abdominal pain
0 They are aged 50 years and over with unexplained rectal bleeding
0 They are aged 60 years and over with:
- Iron-deficiency anaemia
- Changes in their bowel habit, or
- Tests show occult blood in their faeces.
0 Consider in people with a rectal or abdominal mass.
0 Consider in adults aged under 50 years with rectal bleeding and any of the following unexplained symptoms or findings:
- Abdominal pain.
- Change in bowel habit.
- Weight loss.
- Iron-deficiency anaemia.
