Cancer2,3,4 Flashcards
what are cytotoxic chemotherapy
the use of cytotoxic agents to treat cancer.
how do cytotoxic chemotherapy work
they target the mechanisms by which cells divide and grow.
how do they work ? systemically or localised?
they are systemic treatment via blood stream, so it affects the entire body, hence the side effects
do cytotoxic chemotherapy distinguish between cells
NO. they kill both cancerous cells and normal cells
when is the tumor no longer palpable and when is no longer visible by xray
<10^9 - no longer palpable
<10^7 no longer visible
what is the hypothesis for the growth of cancer cells
> cancer cells grow exponentially
on the x axis is time, y axis is number of cancer cells in the body
as the tumour grows, the rate of its growth increases too, and the time it takes for it to double in size gets shorter and shorter
however, once tumour reaches large size, the rate of growth falls
this is probably due to the lack of blood supply and oxygen
this has implications for chemotherapy, because the bigger the tumour, the fewer cells will be in th growth phase.
what is the log kill hypothesis
- that a specific dose of drug kills a constant fraction of cells rather than a specific number.
- the log kill is usually proportional to dose, which in turn is limited by toxicity of the drug
how are chemotherapy scheduled
- the highest dose that can kill the highest possible fraction of cancer cells without intolerable side effect,
- with the shortest interval before the next cycle, to avoid regrowth
- and time given between for recovery of side effects
- with each cycle, fraction of cancer cells reduces
how do you know treatment end point since you can’t see the tumour
using TNM system that have been developed through clinical trials.
what are the types of tumours
- Haematological tumours which affect the blood , bone marrow and lymph nodes.
such as leukaemia, lymphoma, myeloma - solid tumours
describe solid tumours
outside area - closest to blood and oxygen supply so are in growoth phase
inside area - necrotic interstitium .
Cells outside are replicating, therefore getting bigger and bigger. bigger cells = impact surrounding tissue and compresses blood vessels. low blood supply to cells in the middle of the cancer = they die.
so outer layer are growth, inside layer are dead cells.
what is the best way to kill solid tumour
combination of cell cycle specific and cell cycle non specific
how do growing tumours impact drug delivery
these cells impact blood supply travelling through the tumour so it is difficult to deliver drugs.
what does neoadjuvant mean
used to shrink tumour before surgery
how are cytotoxic chemotherapy administers
- intravenously - most common
- oral - most common
- intramuscular injection
- subcutaneous injection
- intracavity
- intrathecal
what are the examples of intravenous administration of cytotoxic chemotherapy and explain them
> cannula =
PICC line = inserted peripheral vein and tip of line sits above right atrium of heart
Hickman line = tunnelled lines under skin of chest, inserted in the central vein w tip sitting above right atrium of the heart.
porta Cath= small chamber buried underneath skin
describe solid tumours
outside area - area of apoptosis (Cell death) #
inside area - necrotic interstitium .
Cells outside are replicating, therefore getting bigger and bigger. bigger cells = impact surrounding tissue and compresses blood vessels. low blood supply to cells in the middle of the cancer = they die.
so outer layer are growth, inside layer are dying.
why are solid tumours difficult to treat
- poor blood supply
- composition of tumour interstitium
- several layers of tissue
- high tumour interstitial pressure that impacts the movement of drug into the tumour
how do growing tumours impact drug delivery
they compress blood vessels, decreasing blood supply to the cells. therefore it is difficult to administer the drugs as they reach tumours through blood supply
what happens when cytotoxic drugs work on the outer layer of the solid tumour
they kill the cancerous cells on the outer layer. the inside cells that had low blood supply and low oxygen levels can now access these nutrients and start to divide.
what are the side effects of cytotoxic chemotherapy for HEAD
- Hair loss
- mood changes, poor concentration / fatigue
what are the side effects of cytotoxic chemotherapy of MOUTH
taste changes
mucositis - inflammation of gut / mouth / Gi tract
> causes speech/swallowing/eating difficulties
what are the GI side effects of cytotoxic chemotherapy
- nausea and vomiting
- poor appetite
- diarrhoea
- constipation
what are the side effects of cytotoxic chemotherapy of hands, feet and skin
- dry skin
- nail changes
- peripheral neuropathy
what are the GENITAL side effects of cytotoxic chemotherapy
- loss of libido
- sterility
how is sterility treated
- storage of eggs
- sperm banking
what are the side effects of cytotoxic chemotherapy of BLOOD
- damage to hemopoietic system (bone marrow toxicity ) - bone marrow is responsible to producing blood cells. chemotherapy damages bone marrow leading to reduction in RBC, WBC (neutrophils), platelets
what are the impacts of toxicity to hemopoietic system
Myelosuppression
less WBC = poor immune system = more risk of infections such as fungal / viral .
pt must be on antifungal /antiviral
how is myelosuppression reduced
- treatment: fractionating dose instead of giving bolus to minimise peak height and assoc toxicity
- timing of doses / hemopoietic monitoring
- transfusions
- CSFs - prevention
- avoid exposure to infections so avoid infected people / large crowds
-watch hygiene especially kitchen