Understanding cancer 6.4

Basic population figures of cancer

• 20 million diagnosis per year

• estimate 33 million cases in 2050 and 19 million deaths

• more common in low-and-middle income countries

• 10.2 male 9.7 female

• 445 per 100,000 US

• prevalence is 53 million - people living with cancer

• mortality is close to 50% - prognosis

• 9.7 m people die every year : 171 male, 126 female per 100,000

what are the most common cancers?

• breast

• prostate

• lung

• bowel

• make up 50% of cancers, obi swap the first 2 based on gender

what does cancer from smoking depend on?

• how much you smoke

• how long you smoke - the longer the worse

• if you stop smoking, risk of cancer reduced rapidly, after 15yrs ur like a non-smoker

• passive smoking increases risk ~ 25% increased risk to spouse, high exposure 17% risk

what increases women risk of cervical cancer?

• HPV virus

• 90% in developing countries due to less vaccinations (protects 70& against virus)

• body often kills the virus - when you have underlying health conditions, less likely to

describe genetic predisposition to cancer and how to reduce it using 1 example

• BRAC1 & BRAC2 DNA repair genes mutations

• these maintain integrity of DNA and repair damage

• mutations increase risk of breast cancer

• 12% → 20-80% risk

• also increases risk of other cancers e.g. ovarian

• age risk especially after 40/50 as cancer takes years to develop

reduce risk:

• screening

• mastectomy - remove breast tissue - 90% risk reduction

• chemoprevention - selective estrogen receptor modulators e.g. tamoxifen, raloxifen (3-50% risk reduction)

• not all cancers from BRAC1/BRAC2 are related to oestrogen modulated drugs - triple negative breast cancer - cancer cells have no oestrogen receptors

Bullet point common risk factors

• age

• lifestyle

• diet

• geography - as different risks globally

• genetics

which ages are likely to have cancer

• above 20 it starts to increase

• this is as we have an ageing population

• increases rapidly after 45

• of course, mortality will also increase with age, as higher cases

risk factors - intrinsic vs non-intrinisc

Examples of non-intrinsic exogenous risk factors

• these are fully modifiable

• breastfeeding: breast tissue gets fully differentiated which provides protection

• the earlier you start your period, and the later you go into menopause, the higher the risk due to increased oestrogen (encourages cells to proliferate)

• diet: low fruit and veg

• e.g. avoid UV - also effects geography risk factor

why is smoking such a big risk factor?

• 50% of smokers will die from smoking-related diseases

• 90% of lung cancers are from smoking

• remember, we said it depends on time and quantity

• length of time being the most important

• the risk stops when you stop smoking, after 15yrs you are like a non-smoker in risk

• 25% second hand smokers also have 25% spouds/ 17% increased risk

what other chemicals can cause lung cancer

• second most common cancer

• asbestos

• radon

• chemicals

which cancers have the lowest prognosis?

• brain 13%

• lung 5%

• pancreas 1%

• after 10 yrs

• this is because they are hard to notice as not on the skin, so you wont know until you have have severe symptoms

Order of progression of a tumour - basic

• hyperplasia - increase in the number of cells

• dysplasia - abnormal growth - changes to size, shape, organisation

describe TNM staging system

• T = tumour - how big is it? bigger it is, the longer its been growing

• N= nodes - when cancer spreads, it can enter lymphatic vessels which are found all over the body, it can enter lymph nodes and become trapped there, and can grow there too

• we check for signs that the cancer has spread there

• M- metastasis - often goes from 90%-15% survival rate for breast cancer

What treatment would you use for local or metastasis?

• local often radiation

• metastasis often surgery

• we want to know how we can target cancer cells without targeting human cells