4. Screening for Breast Cancer

Question 1

What means ‚screening‘?

Answer 1

Systematic application of a test or investigation to people who have not sought medical attention, in order to identify those whose risk of developing a particular disease is sufficient to justify further action

Question 2

What characteristics are important for a good screening programme?

Answer 2

Simple, safe, accurate and acceptable to the public and health professionals; the benefits of screening must outweigh the potential harms or risks.

Question 3

Which examples of screening are the most common?

Answer 3

Heart disease and high blood pressure

Question 4

What is the desired outcome of screening?

Answer 4

Either to prevent disease from occurring in the first place, or to identify the early stages of a disease which can then be treated more effectively, as in screening for early detection of breast cancer.

Question 5

What is population screening?

Answer 5

The aim is to screen everyone in a particular population. In this context, ‘population’ rarely means every citizen of a country. Population screening usually identifies a particular target population group – for example, everyone over the age of 50 years, or all newborn babies – and attempts are made to screen everyone in that category, sometimes at regular intervals.

Question 6

What is the problem with population screening?

Answer 6

• large amounts of people have to be screened, not cost-effective
• inconveniences the healthy individuals who derive no benefit from being screened
• can cause anxiety or unnecessary treatment

Question 7

What is high-risk screening?

Answer 7

Only screening individuals who are likely to be at substantially greater risk of developing a condition than others in their population group

(sometimes called ‘individual screening’ or ‘targeted screening’)

Question 8

What are systematic screening programmes?

Answer 8

An attempt is made to identify everyone who should be screened and invite them to attend for the screening test

Question 9

What is opportunistic screening?

Answer 9

Individuals are entered into a screening programme whenever an opportunity arises, usually when they go to a doctor about something else.

Question 10

Is breast cancer a widespread disease?

Answer 10

Yes. It is the most common female cancer in high- and middle-income countries and it’s increasing worldwide. It is a global health problem.

Question 11

Which screening technique is used to detect breast cancer?

Answer 11

Imaging, and the most common technique is using X-Rays in a mammography. The particular programmes (age, intervals) varies in every country.

Question 12

What are the frequent points of criticism for breast cancer screening?

Answer 12

• the medical value
• cost effectiveness
• concerns about morbity caused by X-rays
• unnecessary treatments or even surgery
• issue about the rights of the patient to refuse screening and then being labelled irresponsible by health professionals

Question 13

Miller asserts that effective treatment and education are vital to breast screening programmes. What are the reasons for these assertions?

Answer 13

Setting up a screening programme without adequate resources for treating breast cancer will have little impact on disease outcome. If there has been no effort to dispel myths and educate the public and health professionals about the potential benefits of screening, the effectiveness of the programme will be undermined.

Question 14

What are the factors that affect the uptake of breast screening?

Answer 14

• accessibility
• adequate opportunities to understand the potential risks as well as the proven benefits (
• inadequate, biased or misleading information means that informed consent to a screening test is jeopardised

Question 15

Which women are less likely to take part on a screening programme?

Answer 15

Women from ‘poor or deprived’ households

Question 16

Which certain associations with breast cancer (screening) can cause problems and women not showing up?

Answer 16

• women who believe the lifetime risk of developing breast cancer is very low may conclude that screening is not worth the inconvenience
• reluctance to undress to the waist in front of strangers, because of religious beliefs and cultural backgrounds
• worrying that it might be painful
• thinking it’s not curable

Question 17

Is cancer an aggressive external entity invading the body?

Answer 17

No, cancer cells are body cells, which multiply in an uncontrolled and inappropriate way

Question 18

How is a mass of cancer cells called?

Answer 18

Tumour

Question 19

Are tumours always dangerous?

Answer 19

No, only the malignant ones which cause damage to organs and tissues and spread around the body. A tumour that is not fatal is called a benign tumour.

Question 20

Sum up the hierarchy of biological organisation.

Answer 20

Atoms - Elements - Molecules - Organelles - Cell - Tissue - Organ - Organ System - Organism

Question 21

What are proteins?

Answer 21

Large macromolecules, the main components of cells, built up from smaller molecules called amino acids. They fold into complex shapes and have a wide variety of functions.

Question 22

What are the functions of proteins?

Answer 22

• form structures that give cells their shape

- enzymes: speed up the chemical reactions inside cells

Question 23

What is the most important part of the cell?

Answer 23

The nucleus, which contains the genetic material, another type of macromolecule called deoxyribonucleic acid or DNA, which is packed tightly into chromosomes

Question 24

What are the mitochondria?

Answer 24

The ‘engines’ that produce the chemical energy for the processes that go on inside the cell

Question 25

What does the endoplasmatic reticulum do?

Answer 25

It is the ‘factory’ of the cell where new proteins are made

Question 26

What are tissues (with examples)?

Answer 26

Groups of specialised cells that work together.

• muscle tissue that allow movement
• adipose tissues that store energy as fat
• epithelial tissue which are layers of cells that form either a barrier (for example the skin), or an interface across which substances are absorbed or secreted (such as the lining of the lungs or the gut)
• connective tissues support and connect cells and structures and contain fibres made of proteins. Examples of those are the bones, and the tendons that connect bones and muscles together

Question 27

What are organs?

Answer 27

Collections of two or more tissues that perform a specific function. For example, the heart is composed of muscles, nerves and connective tissue.

Question 28

What is a body system?

Answer 28

A group of organs and other structures working together. The heart and body-wide system of blood vessels collectively form an organ system called the cardiovascular system.

Question 29

Describe the anatomy of the breast.

Answer 29

. mainly composed of adipose (fatty) tissue and a type of loosely woven connective tissue, which surround and support the milk-secreting milk glands and give the breast its firm, elastic consistency

. the milk glands are divided into branching lobules which resemble bags composed of epithelial cells, including the specialised cells that manufacture and secrete milk

. the lobules open into hollow tubes or ducts (composed of epithelial cells) which carry the secreted milk to the nipple

Question 30

What are hormones and what do they do?

Answer 30

Signalling molecules

Produced in one part of the body, travel around the body in the blood circulation and bind to cells in other organs. They then exert an effect on those cells.

Question 31

What happens in the breast during puberty?

Answer 31

• Ovaries start to produce large amounts of female hormones known as oestrogen’s
• Oestrogen molecules bind to cells in certain body tissues including the breast, and give these cells the signal to grow and multiply, lobules form at the ends of the ducts, amount of fatty adipose and connective tissue surrounding the ducts and lobules also increases

Question 32

What happens during the monopause?

Answer 32

Ovaries stop making oestrogens, the amount of glandular and connective tissue in the breast reduces, but the fatty tissue remains

= much higher percentage of fatty tissue than those of younger women - tissue less dense, interpretation of X-ray images much more reliable for older women

Question 33

What are cancers in epithelial tissue called?

Answer 33

Carcinomas

Question 34

Which breast structures are composed of epithelial tissues?

Answer 34

The lobules and ducts of the milk glands.

Question 35

What is the most common type of breast cancer?

Answer 35

Carcinomas of the lobules or the ducts.

Question 36

What is needed for cell signalling?

Answer 36

A cell needs to contain appropriate receptors to receive signalling molecules like hormones

Question 37

Describe the organisation of a receptor.

Answer 37

Made of proteins, every receptor is only for a certain signalling molecule, like key and lock, stimulating a particular response

Question 38

Describe the cell division stimulated by oestrogen.

Answer 38

1. Oestrogen molecule binds to the oestrogen receptors in a breast cell
2. oestrogen receptor with its bound oestrogen molecule moves into the cell nucleus and interacts with the genetic material, the DNA
3. attaches itself to the DNA and stimulates the cell to read the appropriate genes and manufacture new proteins that are required for the cell to multiply
4. cell then copy of its DNA, so that it contains two copies of the complete genome and some organelles
5. divides into two ‘daughter cells’ such that each daughter receives a full set of DNA and organelles
6. the two daughter cells grow for a while and then can also each divide in response to signals, so several rounds of this process will produce many new cells.

Question 39

Another word for ‚genetic material‘?

Answer 39

Genome

Question 40

If each cell has an identical copy of the genetic information, why are there so many different types of cell?

Answer 40

Because different types of cell ‘read’ particular parts of the DNA code in order to make only the set of proteins necessary for their own specialist form and function.

Question 41

Short sections of DNA that each code for individual protein?

Answer 41

Genes

Analogy: sentences written along the DNA molecule

Question 42

Sum up the bases of DNA.

Answer 42

Adenine with Thymine
Cytosine with Guanine
(base pairs)

Question 43

Why do cancer cells multiply inappropriately?

Answer 43

They lost the ability to communicate with other cells due to a rare mutation that alters certain genes. Those mutations do small changes to the order of bases in DNA.

When that gene is ‘read’ to make the corresponding protein, the instructions will have changed (more of the protein made, or a protein with altered properties, or perhaps none of the protein will be made at all)

Question 44

What are the consequences for the ‘daughters’ of a cell that has experienced a mutation in its DNA?

Answer 44

When the cell divides, the mutation it carries will be copied into the new DNA, so the mutation will be passed on to its daughter cells, and then to their daughters. All of the descendants of the original mutant cell will possess the same mutation.

Question 45

What are mutagens? Name some examples.

Answer 45

Mutagens are factors in the environment that can increase the rate at which sporadic mutations occur in DNA, for example radiation like sunlight (skin cancer) or X-ray imaging, but also DNA-damaging chemicals in food or cigarettes.

One reason why tissues like the skin, lungs and digestive system are particularly susceptible to cancers is that they are directly exposed to mutagens in the environment.

Question 46

Describe the body’s own DNA repair mechanisms.

Answer 46

DNA repair proteins, which are present in every cell, immediately detect and repair the vast majority of mutations

Question 47

Why is cancer more likely to occur with older people?

Answer 47

Older people have been exposed to mutagens for longer and have also had more time to accumulate cells with the several mutations that are required to produce a cancer cell.

Question 48

What is needed for a cancer to become fatal and what is it called then?

Answer 48

When a tumour in a tissue widely spreads and reaches lymph vessels. The term ‚metastasis‘ refers to the process where individual cancer cells may break off and spread to other parts of the body, may establish secondary tumours (metastases) in other body organs which may be fatal.

It is now called malignant cancer or an invasive cancer.

Question 49

Why does the metastatic process make it important to screen individuals regularly for breast lumps?

Answer 49

An early-stage breast tumour is not normally life-threatening, so it is important to detect it as soon as possible in case it acquires the ability to metastasise and spread to essential organs.