Principles of Cancer Treatment Flashcards
What best describes tumour cell growth?
- Gompertzian growth curve - 3 stages (lag, log, stationary)
- latent growth period is clinically SILENT
What are the goals of cancer therapy?
- if possible, to cure
- maintain quality and duration of life
- symptom relief for patients in palliative care
- if all else fails, recruit into clinical trials
What does high growth fraction mean?
many of the cells are actively dividing
What does the slope of the curve depend on?
- ratio of cell division to cell loss
- growth fraction
- TD (doubling time)
What has longer TD than the other?
Solid tumours have longer TD than hematological malignancies.
How can metastasis occur?
- blood
- lymphatic system
What are some common metastatic sites?
- liver
- lung
- lymph nodes
- bone
- brain
- skin
- adrenal glands
What are the three types of cancer treatment?
- surgery
- radiation
- chemotherapy
What are some basic principles of cancer chemotherapy?
- drug kills a constant proportion of tumour cells rather than a constant number of cells -> hence, repeat treatment cycles
- smaller tumour gives better result due to higher growth fraction -> treat asap
- chemotherapy has greatest effect on actively dividing cells
- combination chemo can improve outcomes
- drugs have narrow therapeutic index ->monitor pt
How are cancer treatments dosed?
According to body surface area (BSA)
How do we intensify cancer treatments?
- increase dose
- reduce interval between treatment cycles
What are the drug-related factors affecting response to chemotherapy?
- PK (ADME)
- drug distribution to tumour microenvironment
- mode of action
- combination chemo
What are some tumour-related factors affecting response to chemotherapy?
- tumour growth kinetics (most successful with small tumour and high growth fraction)
- tumour size (less effective on larger tumours)
- site of tumour and tumour vascularization (sanctuary sites are CNS and testes; large tumours have central necrosis)
- tumour cell heterogeneity - resistance (genetically unstable -> mutation gives rise to resistance)
What are some patient-related factors affecting response to chemotherapy?
- pt overall health status
- immuno-competency
- organ functions - renal and hepatic
- treatment history - prior exposure to chemotx and radiotx
- patient’s age (caution in elderly)
What is neoadjuvant chemotherapy?
- systemic tx given before surgery to debulk the tumour
- can also help to eradicate micro-metastases
