Oncology Flashcards
4 tissue types develop from 3 germ cell layers
- ectoderm (outer layer)
- epithelial tissue
- nervous tissue - mesoderm (middle layer)
- epithelial tissue
- connective tissue
- muscle tissue - endoderm (inner layer)
- epithelial tissue
where do cancers develop most in
epithelial cells
types of epithelial cells
- squamous
- cuboidal or columnar
what are epithelial tissues
- line outer surfaces of organs and blood vessels
- line inner surfaces of cavities in internal organs
- compose glands (secrete enzymes, mucous etc)
difference between tumour and cancer
tumour: benign
uncontrolled growth of cell
cancer: malignant
uncontrolled growth of cell
leading to invasion of surrounding tissues
ability to spread to other parts of body (metastasis)
what is metastasis
- detachment from neighbouring cells
- invasion into other tissue layers
- penetration of blood or lymphatic vessels
- escape from those vessels
- establishment & growth at a new site
what are the sites of metastasis
first-pass organ: liver
favoured sites: lung, brain, bone, adrenal gland
vascular organs: kidney
patterns of metastases
- orderly fashion (such as colorectal cancer and cervical cancer)
- random (such as breast cancer and lung cancer)
types of treatment
surgery radiotherapy systemic therapy -cytotoxic chemotherapy -hormonal therapy -targeted therapy -immunotherapy
what are the intent of treatment
radical
- aim is curative
palliative
- aim is to relieve symptoms, delay complications and prolong life
types of radical treatment
definitive
- main/primary treatment, without which cure is not usually possible
neoadjuvant
- before definitive treatment, to facilitate it
- definitive treatment must still be done
adjuvant
- after definitive treatment, to reduce risk of recurrence
explain the use of surgery
- usually definitive treatment, with intent to cure
- complete resection remains cornerstone of curative treatment for many solid tumours
- palliative
explain about the surgery margins
R0 resection - resection of all tumours
R1 resection - incomplete resection (microscopic)
R2 resection - incomplete resection (gross)
explain the use of radiotherapy
- second most effective treatment for caner
- alternative to surgery in many tumour types
- principle similar to surgery
- definitive treatment
- neoadjuvant and adjuvant setting
- palliation
how does radiotherapy work
- radiation ionises water and generates Reactive Oxygen Species (ROS) or free radicals
- highly reactive and will interact/damage molecules in the cell by oxidation
- major target: DNA
- most critical damage is DSB of chromosome
- cells with lethal DNA damage do not die immediately, they go through mitotic cell death (die while trying to divide)
- side effects manifest when cells try to reproduce
- fractionated treatment takes advantage of better tolerance of normal tissues and the difference in recuperative ability between normal and malignant cells
- early responding tissues = tissues which undergo rapid repopulation = expression of radiation damage appears early
- late responding tissue = tissues which normally do not proliferate
