WEEK 1 Oncology Nursing Flashcards
(43 cards)
Define Cancer
A class of diseases characterised by uncontrolled cell division
Identify the two forms of growth within cancer
Direct growth into adjacent tissue (invasion) OR migration of cells to distant sites (metastasis)
Why are cancer cells referred to as “rapidly dividing”
They do not rest and they do not die
Define Carcinogenesis
Normal healthy cells transform into cancer cells as they have had a change in programming and have made it through checkpoints where abnormalities would normally be picked up
Define Carcinogen
A cancer causing agent e.g. Cigarette smoking, UV exposure, Alcohol
Define Well Differentiated tumour cells
Tumour cells reproduce these features well e.g. Breast cells (Clear to tell what the cell is)
Define Poorly Differentiated tumour cells
Tumour cells reproduce these features poorly e.g. Difficult to tell the cell of origin (Where it has come from)
Define Undifferentiated tumour cells
Cannot tell where the cell has come from (No maturation)
What are Proto-oncogenes
Normal growth promoting genes e.g. Growth factors, Cell cycle controlling genes
What are Oncogenes
Mutated form of Proto-oncogenes. Body cells are exposed to personal/environmental conditions that can mutate the genes and alter how the cells function and grow
Describe the process of tumour growth
- Cells normally only divide when needed to replace dying/damaged cells
- Cells are programmed so that they die when no longer needed (Apoptosis)
- With good communication, cells proliferate when required/stop dividing when required
- In cancer cells, something is wrong (genetic code mix up = Cancer cell born)
- Cancer cell divides to produce daughter cells which also divide = Uncontrolled growth and spread
Describe cancer cells “loss of cellular surface contact inhibition”
Normal tissues have balance between cell birth and cell death, tumour cells have an inability to proceed to the resting phase, causing cell birth>cell death = TUMOUR
Define tumour suppressor genes
Function by encoding proteins that block growth promoting proteins “Off switch”. Mutation occurs = No off switch
Identify and describe a common tumour supressor gene mutation
p53 gene “Gate keeper”. Prevents cells that should not be dividing from entering the cell cycle (e.g. those with damaged DNA). When mutated, cells are able to replicate = uncontrolled abnormal cell growth
Define growth fraction
Ratio of the total number of cells to the number of dividing cells. The higher the growth fraction, the more rapidly a tumour mass increases
Define doubling time
Time taken for tumour to double in volume (Average time 2-3 months)
When are tumours usually clinically detectable?
Usually not clinically detectable until they have doubled around 30 times
Describe the Gompertzian Tumour Growth Curve
Describes the decrease in cells doubling time as tumour progression occurs
Describe the Metastatic Cascade
- Growth and progression of primary tumour
- Cells detach and motile cancer cells invade and enter the bloodstream/lymphatic vessels
- If successful, blood/lymph transports them to distant sites where they extravasate and lodge in bones/lungs/liver
- Angiogenesis occurs
- Blood supply to tumour established = Further aggressive growth
Identify the 8 stages of the Metastatic Cascade
- Tumour initiation
- Progression
- Proliferation
- Angiogenesis
- Invasion/Intravasation
- Extravasation
- Colony Formation
- Evasion of host defences
Define intravasation/extravasation
Transport of cancer cells into/out of a blood/lymphatic vessel
Define Prevelance
Measurement of all cancer cases
No. of people with cancer / Total no. of people
Define Incidence
Number of newly diagnosed cases in specified period of time
No. of people developing cancer in period of time/Total population
Define Mortality
Number of deaths attributed to cancer in period of time in a defined population
No. of people dying of cancer in period of time/Total population
