Flashcards in Cancer Deck (22):
what is neoplasm?
a new and abnormal growth of tissue
growth is uncoordinated and persists after the stimuli that initiated change stops
what is carcinogenesis?
malignancy acquired in a "step-wise" process - tumour progression as a result of an accumulation of successive mutations
give examples of carcinogens that increase cancer risk
- radiation (UV, x-rays)
- hormones (oestrogen)
- bacteria, fungi, parasites
what are 4 common targets of genetic mutations?
1) growth-promoting genes (oncogenes)
2) growth-inhibiting genes (tumour suppressor genes)
3) genes regulating programmed cell death (apoptosis genes)
4) genes preventing mutations in the normal cell cycle (DNA repair genes)
what are features of a benign tumour?
- well differentiated
- grow slowly
- do not invade (but can cause pressure effects)
- do not metastasise
what are features of malignant tumours?
- disorganised cells and lack of differentiation (anaplasia)
- grow quickly
- invade locally and into tissues
what are the 4 mechanisms of invasion/metastasis?
- haematogenous (via blood)
- body cavities
- contiguous (adjacent cells/tissues)
how does age affect cancer rates?
- higher incidence >55yos due to increased accumulation of mutations
- BUT some cancers specifically target youth (e.g. leukemias, neuroblastoma, Wilm's tumour)
how does geographical location affect cancer rates?
- stomach cancer is high in japan than USA due to diet
- melanoma is higher in NZ and Australia than Scandinavia due to UV exposure
how does the environment affect cancer rates?
- UV light
- occupational agents (asbestos)
- existing infections (viruses, HPV)
how do genetics affect cancer rates?
- autosomal dominant: inherited cancer syndromes where a single mutant gene is responsible
- autosomal recessive: inherited defective DNA repair mechanisms
- unknown: familial cancer syndromes
outline the stages of diagnosis and staging
1) clinical symptoms/signs
2) screening programmes
3) surgical/radiological guided biopsy
4) +/- tumour markers
5) radiological staging pre-op
6) laboratory methods
what is involved in radiological staging pre-op?
- CT scan
- MRI scan
- PET scan
what is involved in laboratory methods?
- cytology test (examining cells under microscope)
- histology (examining tissues under microscope)
what are the clinical effects of tumours?
- increased basal metabolic rate
- reduced fat/muscle bulk
what is the main staging system based on?
- size of primary lesion
- spread of regional lymph nodes
- presence of metastases
what 3 cancers are screened for in the UK?
- breast cancer
- cervical cancer
- bowel cancer
describe the breast screening programme
- most common female cancer in UK
- higher risk > 50yos
- involves a mammogram
describe the cervical screening programme
- 11th most common cancer in UK
- most common in females <35yos
- detectable with easy, low cost process involving a smear
describe the bowel screening programme
- 1 in 20 develop bowel cancer
- 3rd most common cancer
- FOB (fecal-occult-blood) testing and progress to colonoscopy if +ve
what does a successful screening programme include?
- reliable prediction of tumour behaviour
- treatment available
- target population has enough people at risk to justify expense
- cost-effective and reliable screening tools