Intro to Cancer Tx Flashcards
4 most common cancers in Canada
Lung, prostate, breast, and colorectal
“An estimated 1 out of ___ Canadians are expected to develop cancer during their lifetimes”
2
50%!!
T or F: Heart dz is the leading cause of premature death in Canada.
F
It’s now cancer
Two major reasons for rising incidence of cancer
increasing human lifespan, population growth
T or F: Cancer cells can arise only from certain cell types, such as rapidly dividing intestinal cells.
F
Cancer can arise from ANY cell type
Characteristics of a cancer cell
- unctrled growth (lack of or dysfn’al feedback mechanisms)
- invades surrounding tissue
- decreased cellular differentiation (i.e. lack of functionality found in cell of origin)
- metastasize
- MANY other diffs in biochemistry, genetics, etc. that distinguish cancer cells from benign cells
What does tumor GRADING tell us?
Cancer’s aggressiveness (i.e. how bad it looks)
How is a tumor graded?
by looking at degree of differentiation (i.e. how diff it looks from the original cell of origin) and mitotic rate (i.e. how fast it’s growing)
How would a tumor with a higher grade be described?
It has little resemblance to a normal cell and many of its cells are in active cell division
What does tumor STAGING tell us?
Extent of cancer (i.e. how far has the cancer spread)
How is a tumor staged?
by looking at size of primary lesion (T), whether lymph nodes are involved (N), and metastases (M)
How many stages are there?
5: Stage 0 to stage IV
Tx modalities for cancer:
surgery, radiation, drugs (chemo and more), immunotx
What do cytotoxic drugs do?
interfere with or damage cellular DNA, leading to cell death
How does immunotx tx cancer?
It activates pt’s immune sys against cancer cells
Define growth fraction
Fraction of cells that’re undergoing mitosis in a given tissue/tumor
How does growth fraction change as tumors get bigger?
Growth fraction decreases
Why does the growth fraction change as a tumor gets larger?
growth fraction decreases because: more and more cells are growing farther away from blood vessels, there’s an accumulation of toxic metabolites, and there’s less cell-to-cell communication
Clinically detectable mass size
1 gram of tissue = 1x10^9 cells = 1 cm^3
MOA of cytotoxic drugs
interfere w/ production and fn of DNA/RNA > apoptosis
What specifically do cytotoxic drugs target?
Processes within the cell cycle
What is the “guardian of the genome”?
p53 suppressor gene
What is the job of the “guardian of the genome”?
to sense genomic damage and attempt reparation > if DNA can’t be repaired, it initiates apoptosis
What is a significant mechanism for drug resistance in cancer?
mutant p53 suppressor genes > no more apoptosis
List the 5 categories of cytotoxic agents
alkylating agents
anti-metabolites
antitumor antibiotics
antimitotic agents
topoisomerase inhibitors
What’re cell cycle specific drugs?
cytotoxic drugs that’re effective against cells that’re in the process of dividing
What kind of tumors are cell cycle specific cytotoxic drugs most effective against?
Tumors w/ high growth fraction
What’re the two types of cell cycle specific drugs?
Phase-specific and phase non-specific agents
What’re cell cycle non-specific drugs?
Cytotoxic drugs that have activity against RESTING cells
What kind of tumors are cell cycle non-specific cytotoxic drugs most effective against?
lg tumors w/ low growth fraction