Cancer 3- Principles of Cancer TX Flashcards
Aoife
Principles of Cancer Tx
Tx if cancer localised (2)
- Surgical removal
- Tx with drug or radiation tx to kill residual cancer
Principles of Cancer Tx
What would an ideal cancer tx be
One that removed all the cancer cells without affecting normal cells
Principles of Cancer Tx
What are txs based upon (2)
- Killing cancer cells
- Preventing further growth of tumour
Principles of Cancer Tx
What is the best approach
Surgical removal of a tumour mass
Principles of Cancer Tx
Limitations of surgical removal as a tx
- Cancers of blood (leukaemias) not amenable to surgeries
- Same true for cancers that have metastasised to inaccessible sites like bone and brain
Principles of Cancer Tx
What tx is widely used in addition/alternatively to surgery
Drug tx
Principles of Cancer Tx
What is the cytostatic effect
The prevention of cell proliferation
Principles of Cancer Tx
What is the cytotoxic effect
The killing of cancer cells
Principles of Cancer Tx
What does chemo having a broad cell specificity mean
It effects all cell processes such as DNA synthesis and cell proliferation common to all cells
Principles of Cancer Tx
What is the disadvantage of chemo having broad cell specificity
Side effects ensue.
Fast growing cells targeted -> hair and taste loss
Principles of Cancer Tx
What cancers (2) are hormone txs used to treat and why
- Prostate
- Breast
Hormone txs effect the growth of cells in these cancers
Principles of Cancer Tx
Explain the principle of radiotherapy being used
DNA can be irreversably damaged by ionizing radiation such as X rays which are used in radiotherapy tx along w surgery
Principles of Cancer Tx
What will cytotoxic drugs do
Potentially cure the patient
Principles of Cancer Tx
What will cytostatic drugs do
Prevent growth but not eliminate the cancer
Principles of Cancer Tx
How would the future tx of angiogenic drugs do?
They would prevent angiogenesis and therefore prevent metastatic growth
Principles of Cancer Tx
What are some prognostic factors
Prognostic factors to assess prognosis:
1. Tumour size
2. Tumour spread
3. Tumour markers in the tissue or blood associated with the tumour
Principles of Cancer Tx
Remission
Decline in cancer size as a result of tx
Principles of Cancer Tx
Relapse
Reappearance of a cancer
Principles of Cancer Tx
Screening programmes for early detection exist for? (3)
- Cervical
- Breast
- Colon
Principles of Cancer Tx
Preventing cancer cells from generating can be achieved with what and e.g:
With vaccinations. E.g: cervical cancer vaccine, against Human Papilloma Virus
Definition of a response
Complete response
Cancer disappears completely
Definition of a response
Partial response
Partially removed, some remains
Definition of a response
No change
Remains static
Definition of a response
Progressive disease
Continues to grow
Patient Criteria: Stage and Grade
the 2 criteria in defining cancer
- Tumour size & degree of spread -> STAGE of disease
- Cellular characteristics of the cancer -> GRADE of disease
Patient Criteria: Stage and Grade
Advanced stage cancer description
One that is large and has invaded its surrounding tissues or organs and metastised to other parts of the body
Patient Criteria: Stage and Grade
3 criteria cancer staging is based on
TNM system:
1. Tumour size
2. Spread to lymph nodes
3. Metastasis to distant sites
Patient Criteria: Stage and Grade
What does a low grade tumour have in comparison to a high grade tumour
- A low grade tumour has histological resemblance to the tissue of origin
- A high grade tumour has undergone so many changes that it only marginally resembles tissue of origin
Patient Criteria: Stage and Grade
Criteria for grading (3)
- Number of mitoses
- Irregularities in nuclear shape
- Relative architectural resemblance to normal tissue
How does early detection affect prognosis
Time equates with increased cullular changes towards aggressiveness so the earlier it can be detected, the fewer changes it has undergone and the greater chance of it responding well to tx
Surgery
How can surgical removal result in a cure
If all the cancer cells are removed it can result in a cure
Surgery
What are the 2 tx options after surgery and why are they more successful after surgery
To kill the remaining cancer cells:
1. Drug therapy
2. Ionising radiation therapy
These are more likely to be successful due to the debulking effect of cell removal
Radiotherapy
How does radiation kill cancer cells
Radiation such as xrays damage DNA and kill cancer cells
Drug tx
Chemotherapy definition
The term given to drugs whose actions are largely based on blocking cell proliferation
Drug tx
What type of cells is chemo most effective against
Rapidly dividing cells
Drug tx
Efficacy of chemo depends on (2)
- Conc of drug reaching tumour
- Duration of this exposue
Drug tx
How can the side effects of chemo be managed
By using combinations of drugs with different toxicities
Drug tx
What is primary chemo
First line tx for local disease
Drug tx
What is adjuvant chemo used for
It is the agent used in addition to other treatments (surgery) to kill remaining cancer cells. (adjuvant chemo used post mastectomy)
Drug tx
What do chemo patients have a tenfold increased risk of
Leukaemia
Chemotherapy
what can chemotherapeutic agents be categorised into (3)
- Whether they alkylate DNA (alkylating agents - transfer an alkyl group from one molecule to another)
- Antagonise metabolites needed for DNA synthesis (antimetabolites)
- Others are natural products from plants and fungi
Chemo side effects
What are some of the side effects of chemo and why
- Anaemia, Thrombocytopenia, Neutropenia as normal haemopoietic cells in bone marrow particularly sensitive to chemo
- Patient more prone to infection due to destruction of immune cells
- Hair loss as hair follicles are rapidly dividing cells
- Nausea & vomiting -> treat w anti emetic drugs
Hormone tx
Principle of hormone tx
A tx that uses medicines to block/lower amount of hormones in the body to slow down/stop the growth of cancer
Hormone tx
Explain how specific properties of cells are exploited with hormone tx
- Steroid hormones are required for the growth of prostate and breast cancer
- Responsive cells must have specific receptors for the steroid hormone and as most cells in the body dont have these receptors, they are unaffected by the hormone therapy used
- Hormone tx prevents excess steroid synthesis and blocks their effects at the target cell via the receptor machinary
Hormone tx
Examples of the hormone txs used for 1. breast 2. prostate cancer
- Tamoxifen to treat breast cancer
- Anti androgens therapy to treat prostate cancer
New forms of tx
4 new forms of tx
- Angiogenesis: txs prevent new blood vessel formation in cancers
- Immunotherapy: mechanisms that use the immune system to facilitate the attack and lyse of tumour cells
- Tyrosine Kinase Inhibitors: Tx attempts to intefere w enzymes and proteins involved in cell signalling pathways that control cell proliferation
- Gene therapy
8 methods of general support therapy
- Blood product support -> red cells for anaemia, platelet transfusion for thrombocytopenia
- Haemostatic support -> Vit K or fresh frozen plasma
- Antiemetic therapy -> nausea & vomiting side effects of chemo
- Nutritional support -> loss of appetite can cause atrophy, tongue cells affected by chemo, can be prescribed high calorific supplement if can eat orally
- Reproductive issues -> egg retrieval or sperm collection
- Psychological support
- Pain support
- Tx for infections