Principles of cancer therapy Flashcards
What are some principles of cancer treatment?
- Is surgical resection or curative treatment possible, or will they then be limited to palliation
- What is the best treatment?
- Are diff treatment options available
Cancer surgery
For cure, most effective treatment.
May be done for biopsy, staging, local control -> not for cure
Radiation therapy
Ionising radiation causes cell death by damaging DNA and creating free radicals from water that damage membranes and proteins etc.
Therapeutic: usually in the form of external beam; must be planned by area of body and dose sensitive.
Chemotherapy
- Using chemicals to kill disease causing cells in the body (cancer cells, bacteria, viruses.)
- is not drug therapy which uses chemicals to modulate body processes
What is selective toxicity?
The goal of chemo, when toxicity is produced in the cancer cell without or with less effect to host cells.
Is achieved by exploiting differences between normal host and bad cells: a unique target, structurally different or functionally different.
What is the therapeutic index?
Indicator of ST
The dose required to produce toxic effect/ dose required to produce desired effect
PD of cancer therapy
The curve of effect vs drug conc of normal cells is shifted to the right, meaning drugs at lower conc will kill more cancer cells than normal.
Therapeutic index will be positive?
8 kinds of cancer chemo drugs?
What do methotrexate, paclitaxel
APATAHT V
Alkylating agents; platinum based; antimetabolites; topoisomerase-interactive; antimicrotubule; hormonal; targeted therapies; vascular targeting
Tumour growth and chemo killing
Combination?
Starts as one cell and grows and grows. Chemo will kill a constant proportion of tumour cells, hence repeated doses required. Needs to often be continued after clinical disappearance
Combination more effective: some activity as a single agent; diff mechanisms of action and diff side effect profiles
What is an example of combination therapy?
BEP
Bleomycin: induces DNA break; lung toxicity
Etoposide: topoisomerase poison; bone marrow
CisPlatin: induces DNA crosslinks; peripheral nerves
Adverse effects of chemo due to pharmacological mechanisms ( 4)
Antiproliferative- alopeica, myelosuppression, sterility
Mutagenesis; second cancers, teratogenic
Microtubule disturbance: neurotoxicity (peripheral)
Sex steroid deficiency: decreased libido
When to use chemo?
For cure; with surgery; with radiotherapy; palliative care
