Treatment of Cancer Flashcards
Metastasis definition:
Invasion of cancer into surrounding tissue, and colonization of other locations in the body
Angiogenesis definition:
Growth of new blood vessels from existing vasculature
Why is angiogenesis critical for tumour growth?
Allows new abnormal cells to grow by providing oxygen and nutrients
Tumours secrete ___ to induce blood vessel growth:
GFs
Metastasis occurs when:
Cells detach from parent tumor, enter blood/lymph vessel, exit from circulation, proliferate into the new environment
Carcinoma:
Cancers of epithelial cells lining the surface of organs
Sarcoma:
Cancer of muscle, bone, fat, cartilage, or connective tissue
Leukemia:
Cancer of white blood cells or blood precursor cells
Lymphoma:
Cancers of bone-marrow derived cells that affect the lymphatic system
Blastoma:
Cancer thought to arise from immature or embryonic tissue
80-90% of cancers are what type?
Carcinomas
Why are the majority of cancers carcinomas?
Epithelial cells are the site of extensive cell proliferation and frequent exposure to chemical and/or physical damage
Certain genes that are reported to play a critical role in cancer development:
- DNA proofreading/ repair genes
- Genes that maintain chromosomal integrity
- Oncogenes
- Tumour suppression genes
Tumour progression depends on various factors:
- Mutation rate
- Number of cells in the population
- Rate of cell division
In a healthy cell, rate of damage is equal to ____
Rate of repair
During pathological situations, rate of DNA damage is ____ than the rate of repair:
Greater
How is the risk of developing cancer affected in an individual with inherited cellular DNA mutations?
Increased risk of developing cancer
Following mutations, oncogenes acquire ____
Gain-of-function
Following mutations, tumour suppressor cells acquire ___
Loss-of-function
What does gain-of-function refer to in mutated oncogenes?
Mutated oncogenes are expressed at high levels, resulting in cell growth & an increase in mitosis
Examples of oncogenes:
- Hormones
- GFs
- Receptors
- Cell signaling molecules
- TFs
What is a tumour suppression gene’s main function?
To protect cells from cancer pathology
End result following mutation of an oncogene or tumour suppressor gene:
Increase in cell growth
The seven principles of cancer therapy:
- Cure requires death of all tumour cells
- Drugs kill a constant proportion of tumour
- Tumours detected later require prolonged treatment
- Drugs have narrow therapeutic index
- Drug combinations can increase effectiveness and decrease adverse cells
- Intermittent high-dose therapy is more effective
- Adjuvant therapy may decrease metastases
Cancer therapy for terminal patients:
Palliative care, focuses on relieving and preventing suffering
Localized therapies:
Surgery, radiation
Systemic therapy:
Chemotherapy, hormone therapy (has effects on all regions of the body)
The ultimate goal of pharmacologic cancer treatment:
Targeted therapy
Factors influencing patient survival:
- Time of initiation of treatment
- Timing of the treatments
- Drug combinations
Cellular activity during G0 phase:
Cells cease division
Cellular activity during G1 phase:
Cells grow
Cellular activity during S phase:
DNA replicates
Cellular activity during G2 phase:
Cells prepare to divide
The addition of therapeutics during ___ phase would allow slow-growing tumours to be treated early:
Proliferative
First-order kinetics:
Elimination of the drug is proportional to the plasma concentration of that same drug
Chemotherapy kills cancer cells via:
First-order kinetics
At the time of detection, how many cancerous cells are there?
Over one billion
Failure of anticancer drugs can be due to:
- Lack of specificity (side effects and dosage limitations)
- Cancer has developed resistance to the treatment
Ways cancerous cells may acquire resistance to treatment:
- Some neoplastic cells are inherently resistant
- Develop mutations through growth
- Multidrug resistance- A selection of cells expressing amplified p-glycoprotein that pumps drugs out of the cell
Chemotherapy side effects:
- Myelosuppression
- Nausea, vomiting, diarrhea
- Alopecia
- Decreased sperm count, menopause, teratogenicity
- Secondary carcinogenicity
Ideal combination of cancer chemotherapy drugs:
- Drugs that offer synergistic action
- Drugs that have different mechanisms of action and resistance pathways
Main things to consider when deciding on cancer treatment:
- Long term gain vs. the risk
- Chance of successful treatment vs. the quality of life
