Environmental causes Flashcards
(40 cards)
What is latent period?
The context of a fixed time between exposure and appearance of malignancy
Why is age at expression used?
Regardless of age at exposure, induced tumours tend to appear at the same time as those spontaneously occurring due to additional steps being required later in life
When are exposures most impactful?
Young ages e.g. females exposed to radiation have a highly increased risk of thyroid and breast cancer whilst over 50s exposed show little or no risk
How many cancer deaths does smoking cause?
43,000 in the UK in 2010, 27% of all cancer deaths
Ratio of cancers caused by smoking
3 in 20 (15%)
What cancers does smoking cause?
lung, mouth, bladder, colon, kidney, throat, nasal cavity, voice box, oesophagus, lip, stomach, cervix, liver and pancreas
Other tobacco linked cancer
Smokeless tobacco use in people with leukemia causes cancers of the mouth
ETS causes lung cancer
Carcinogens in cigarette smoke
more than 100, including benzene and acrolein
Acrolein sources
the manufacture of chemical products
herbicides in recirculating water systems
tobacco smoke
emissions from combustion of fuels, wood and plastics
ambient air pollution
e-cig vapour
high-temperature roasting
deep-fat frying
What increases risk of mouth, voice box and oesophagus cancers in smokers?
drinking more than 2 drinks/day
What are the strongest links between obesity and cancer?
Breast cancer in older women
endometrium, kidney, colon and oesophagus cancers
What are the strongest links between obesity and cancer?
Breast cancer in older women
endometrium, kidney, colon and oesophagus cancers
What cancers do physical inactivity cause?
colon and breast cancer
What are the statistics for inactivity and obesity causing cancers?
25-30% of colon, breast (postmenopausal), endometrial, kidney and oesophagus cancers
What cancers does drinking cause?
mouth, throat, voice box, liver and oesophagus cancers
some evidence linking alcohol to breast cancer
What are sources of UV radiation?
the sun, sunlamps and tanning beds
What DNA damage does UV radiation cause?
Cyclobutane dimers are formed between two adjacent pyrimidine bases (T-T or T-C), the misrepair of which leads to DNA gene mutations
What are sources of UV radiation?
the sun, sunlamps and tanning beds
How does UV radiation cause melanoma and other skin cancers?
UV radiation causes premature ageing of the skin and DNA damage. Since UV radiation is low energy, it has poor penetration so primarily affects the skin. 240-320nm range UV induces excitation of the bases in nucleic acids which become stable photochemical changes, with UVB rays being the most carcinogenic at 290-320nm.
How many pesticide ingredients are carcinogenic?
Of 900, 20 have been found carcinogenic in animals although not all have been tested
What pesticides have been banned?
ethylene oxide, amitrole, some chlorophenoxy herbicides, DDT, dimethylhydrazine, hexachlorobenzene, hexamethylphosphoramide, chlordecone, lead acetate, lindane, mirex, nitrofen and toxaphene
Who is at risk from pesticides?
farmers, pesticide applicators, crop duster pilots and manufacturers
Which cancers do pesticides cause?
blood and lymphatic system cancers
cancers of the lip, stomach, lung, brain and prostate
melanoma and other skin cancers
Which viruses are linked to cancers?
HPV -> cervical and anal cancer
Hep B (HBV) and Hep C (HCV) -> liver cancer
Epstein-Barr virus (EBV) -> lymphoma (rare outside immunodeficiency)
Kaposi’s sarcoma-associated herpesvirus (KSHV)/human herpesvirus 8 (HHV-8) -> Kaposi’s sarcoma (rare outside immunodeficiency )
HIV -> immunodeficiency which can trigger other cancers
