Cancer therapy Flashcards
biology of cancer
abnormal patterns of gene expression
- oncogenes
- tumour supressor genes
point mutations in control genes trigger these
changes are either:
- cumulative mutations with division
- non-mutational changes
features of cancer
growth factor independence
insensitivity to anti-growth signals
avoidance of programmed cell death (apoptosis)
ability to recruit a dedicated blood supply
ability to invade adjacent normal tissues and metastasise to distant sites
reprogrammed energy metabolism
evading immune destruction
imaging in cancer
early detection - screening
assessment of identified cancer - staging
panning cancer treatment - radiotherapy
imaging in cancer - methods
ultrasound scanning
‘plain’ X-ray
CT imaging
MR imaging
Radionucleiotide imaging
- SPECT
- Position emission tomography and PET-CT
Cancer treatments
surgical
chemotherapy
radiotherapy
combination treatments
palliative therapy
aims of cancer surgery
remove tumour completely before spread
- remove regional lymph nodes if lymphatic spread suspected
most effective if small encapsulated tumour
need clear margin to reduce recurrence
Effects of cancer surgery
reduced tissue bulk
- cosmetic (breast, oral)
- functional (colorectal)
often reconstruction needed
requires GA
- general health effects
Surgery - side effects
cosmetic and functional deficit
local infection/wound separation
lymphatic oedema in affected area
general surgical consequences
- deep vein thrombosis DVT
- HAI - hospital acquired infection
often not curative - but reduces bulk of tumour and this may help ease symptoms and severity
chemotherapy - principles and aims
kill tumour cells without harming host cells
- rarely possible
- usually relies on tumour cells having faster replication rate than normal host cells
targeting drugs to cell markers or growth factors now reduces toxicity
- hormone treatments
- growth factor treatments
Side effects of chemotherapy
rapidly diving cells killed
- hair loss
- oral ulceration
- bone marrow suppression - WBC and platelets
damage to DNA of remaining cells
- risk of later cancers
- fertility damage
- induction of menopause
drug specific effects
- naste loss
- nephrotoxicity
radiotherapy - principles and aims
ionising radiation damage to cellular DNA
total dose usually delivered over multiple sessions
- fractionated
radiotherapy - effects
kills the tumour cells
- has to be delivered over days as not all cells dividing at same times
gives moderate/high dose to overlying tissue ]
- skin tissue burn or mucosal ulceration
radiotherapy - side effects
general tiredness
burns
- clothing/shaving/sunlight issues
- may leave permanent pigmentation and telangiectasia
hair loss in treatment area
dry mouth/taste loss if head and neck
menopause induction in premenopausal women
- if pelvic/abdominal radiotherapy
What is adjuvant therapy?
additional treatment to improve cancer outcome
- target tumour cells more effectively
- reduce risk of metazoic or recurrent disease
examples of adjuvant therapy
hormone treatment - tamoxifen
targeted chemotherapy - Herceptin
metates prevention - bisphosphonates
