What is Breast Cancer?

Breast cancer is the second most common cancer in the UK, representing 15% of all new cancer cases, and is the most common cancer amongst women. There are around 56,000 new cases of breast cancer every year in the UK, which is over 150 cases every day. In women, on average there were 55,545 new cases each year, and in men, there were 375 new breast cancer cases, based on 2016–2018 data.

According to the same data, 18% of breast cancers were in women under 50, 82% in those 50 or older and 24% occurred in women over 75. According to Breast Cancer UK a woman born after 1960 and living in the UK has an estimated 1 in 7 lifetime risk of developing breast cancer; a UK man’s lifetime risk of developing breast cancer is around 1 in 870. Transwomen and non-binary people can also get breast cancer.

The above figures may appear disturbing; however, according to Cancer Research UK, survival from the illness in the UK has doubled in the last 40 years. These days, 76% of people live for ten or more years after they receive a diagnosis.

Australian singer Kylie Minogue was 36 when she was diagnosed with breast cancer in 2005, but thanks to eight months of chemotherapy and radiation in 2006, her breast cancer went into remission. Seventeen years after her diagnosis, Kylie is still able to perform for millions of her fans, with her next concert planned for 24 February 2023 at The Domain, Sydney.

What is breast cancer?

Breasts are made up of:

• Fat.
• Glandular tissue divided into lobes (each containing lots of lobules).
• A network of ducts or milk ducts – the ducts spread from the lobes towards the nipple.
• Connective tissue.

One breast is usually smaller than the other. Your breasts may feel different at different times in the month and it is common for breasts to feel lumpy just before your period. Your breasts also change during pregnancy and you may notice that they become bigger and feel more tender. After the menopause, fat gradually replaces the glandular tissue, which is less dense.

Breast cancer starts in the breast tissue, most commonly in the cells that line the milk ducts of the breast. It occurs when abnormal cells in the breast grow in an uncontrolled manner. It can happen in both men and women, but women are at greater risk due to their breast development and lifelong exposure to oestrogens. Cells that grow abnormally can form tumours. Breast cancer occurs when breast tumours spread.

Breast cancer can spread outside the breast through blood vessels and lymph vessels. When breast cancer spreads to other parts of the body, it is said to have metastasised.

Breast cancer is a diverse group of diseases. It may be invasive or non-invasive.  Non-invasive breast cancer is an early form of breast cancer, which remains localised to the breast.

The most common form is ductal carcinoma in situ (DCIS); if left untreated DCIS may become invasive. Another common type of non-invasive breast cancer is lobular carcinoma in situ (LCIS). This type of carcinoma is not cancerous, so does not spread, although its presence is correlated with an increased chance of developing cancer at a later stage.

The most common types of invasive breast cancer include:

• Invasive breast cancer of no special type (NST) – This is formally known as invasive ductal carcinoma, where cancer cells have grown through the lining of the milk ducts into surrounding breast tissue. It is called NST as when cells are viewed under a microscope, they have no special features. It accounts for around 70% of all invasive breast cancers.
• Invasive lobular breast cancer – This is where cancer cells in the lobules, the milk-producing glands, have spread into surrounding breast tissue. It accounts for around 15% of all invasive breast cancers.
• Inflammatory breast cancer – This is a rare, fast-growing type of breast cancer caused by breast cancer cells blocking the small lymph channels in the breast and skin. In this type of breast cancer, the skin of the breast looks red and inflamed. It accounts for around 1% to 5% of invasive breast cancers.
• Paget’s disease of the breast – This is a rare type of breast cancer that causes change to the skin of the nipple, similar to eczema.
• Hormone receptor-positive cancers – These are those that have additional receptors for oestrogen, progesterone and/or human epithelial growth factor 2 (HER2+). Around 75% of breast cancers are oestrogen receptor-positive (ER+). Cells from these tumours produce additional oestrogen receptors – proteins which bind oestrogen and depend on oestrogen to grow.
• Triple-negative breast cancer – This does not have additional receptors for oestrogen, progesterone or HER2. It is more common in younger women and tends to be more aggressive and more difficult to treat. Around 15% of breast cancers are triple-negative.

What are the signs and symptoms of breast cancer?

Different people have different symptoms of breast cancer. Some people do not have any signs or symptoms at all. The first thing someone commonly notices is an abnormal lump in their breast.

Some warning signs of breast cancer can include:

• A new lump in the breast or in the armpit.
• Thickening or swelling of part of the breast.
• Irritation or dimpling of breast skin.
• Redness or flaky skin in the nipple area or the breast.
• Pulling in of the nipple or pain in the nipple area.
• Nipple discharge other than breast milk, including blood.
• Any change in the size or the shape of the breast.
• Pain in any area of the breast.

No breast is typical. What is normal for you may not be normal for another woman. Most women say their breasts feel lumpy or uneven. The way your breasts look and feel can be affected by getting your period, having children, losing or gaining weight, and taking certain medications. Breasts also tend to change as you age.

Many conditions can cause lumps in the breast, including cancer. But most breast lumps are caused by other medical conditions. The two most common causes of breast lumps are fibrocystic breast condition and cysts. Fibrocystic condition causes non-cancerous changes in the breast that can make them lumpy, tender and sore. Cysts are small fluid-filled sacs that can develop in the breast.

What causes breast cancer?

There is no simple cause of breast cancer. A variety of risk factors come together to make you more, or less, susceptible. Some of these risk factors are inherited, some are incurred throughout your life and others are present in the environment in which you live.

Naturally occurring oestrogens and some other hormones in our bodies can influence the risk of developing breast cancer, mainly because of their ability to increase rates of cell division and promote the growth of oestrogen-responsive tumours.

What are the risk factors of breast cancer?

Anything that increases the risk of getting a disease is called a risk factor. However, having one or more of the following risk factors doesn’t mean that you will definitely get breast cancer. Many people who have these factors never get it and some people with no risk factors develop it.

Some of the factors which may be risk factors include:

• Being a woman – This naturally means having more breast tissue that is susceptible to breast cancer and a higher lifetime exposure to oestrogens, which can stimulate cell division and growth and promote the growth of certain types of breast tumours.
• Being transgender – A transgender woman taking medication to lower male hormones and boost female hormones may have an increased risk of developing breast cancer.
• Age – This is the most significant risk factor for female and male breast cancer. As you age, mutations accumulate in your cells, including those that increase your risk of cancers, including breast cancer.
• High breast density – This is the most significant risk factor for breast cancer after being a woman and age. Breast density, also known as mammographic density, can only be identified by a mammogram – a breast X-ray – and is partly genetic and partly influenced by environment and changes over a lifetime.
• Starting your periods early, before 12 years of age, or reaching menopause late, after 55 years, are factors that contribute to a higher risk of breast cancer. This is thought to be related to the longer time period that high concentrations of oestrogens are circulating in your body.
• Being tall – This can make you more susceptible, possibly due to the higher levels of growth hormone and certain growth factors in your body during early development.
• A birth weight above 4kg (8–9lbs) and a large early body size before the age of 18 means you are at an increased lifetime risk of developing breast cancer.
• Ethnicity – A report found that the risk of breast cancer is higher in white women than in any other ethnic group; this is at least partly due to lifestyle factors.
• Higher levels of naturally circulating sex hormones – Oestrogen, progesterone and testosterone – increase breast cancer risk. Postmenopausal women with higher levels of naturally circulating oestrogen have around twice the risk of breast cancer compared to those with lower levels.
• Having children after the age of 30 or having no children puts you at greater risk of breast cancer. Having more children at a young age reduces your risk. Breastfeeding reduces your risk and the longer you breastfeed the more your risk is decreased.
• Being overweight – Adult weight gain is a well-recognised risk factor for breast cancer in postmenopausal women, mainly due to increased levels of circulating oestrogens.
• Lack of physical activity – This is a risk factor because physical activity helps lower levels of certain growth factors and hormones, including oestrogen. Higher levels of these are associated with cancer development and progression.
• Drinking alcohol – This increases your risk, and is thought to be because alcohol can raise the concentration of circulating oestrogens. Also, alcohol is broken down in breast tissue to produce by-products which may damage DNA.
• Shift work or exposure to light at night – This may increase breast cancer risk. Both may be responsible for decreased production of melatonin, a hormone which is protective against breast cancer.
• Smoking – Especially if you begin at an early age or have smoked for many years, increases your risk.
• Use of the contraceptive pill and implants which are combined synthetic oestrogen and progesterone, increase breast cancer risk slightly. Risk increases with a longer duration of use and is no longer apparent 5–10 years after use has ceased.
• Use of combined Hormone Replacement Therapy (HRT) that includes synthetic oestrogen and progesterone, carries an increased risk especially if you use it over a long period. This risk decreases following cessation of use and is less, or no longer apparent for short-term users, 5–10 years after use has stopped. HRT containing oestrogen alone may be associated with a slight increase in risk.
• A history of certain types of benign breast disease or a previous breast cancer diagnosis means you have an increased risk of breast cancer. Breast cancers commonly occur in women with atypical hyperplasia and proliferative disease without atypia. Two types of non-invasive breast cancer, lobular carcinoma in situ and ductal carcinoma in situ, are also associated with an increased risk of breast cancer.
• A family history of breast cancer is relevant but as breast cancer is common, having a relative with the disease doesn’t necessarily indicate you have a genetic predisposition. Having a first-degree relative such as a mother, sibling or daughter who has developed breast cancer, especially at a young age, approximately doubles your risk.
• Single gene mutations such as BRCA1 and BRCA2 are uncommon and account for around 4% of breast cancers. Recent studies suggest the risk of getting breast cancer by the time you reach 80 if you carry a faulty BRCA1 or BRCA2 gene is around 70%. See the NHS website for comprehensive advice about genetic testing.
• Genetic variation in multiple genes and other regions of DNA is also associated with an increased breast cancer risk. Genetic variation, including single gene mutations, is thought to account for around a fifth of all breast cancers.
• Radiation exposure – This may be as a result of radiotherapy for medical treatment, or from other high-energy sources, for example multiple chest X-rays, particularly during puberty. This can damage your DNA which increases your risk of mutations and chances of developing breast cancer.
• Environmental carcinogens – These may be present in polluted air, for example dioxins and polychlorinated hydrocarbons, or as a result of working in hazardous occupations. These can increase breast cancer risk.
• Endocrine Disrupting Chemicals (EDCs) –Tthese are found in many everyday products and can mimic, block or interfere with hormones in the body and may influence the development of breast cancer.
• Exposure to diethylstilboestrol (DES) during pregnancy or in pre-birth – DES is a synthetic oestrogen and endocrine disrupting chemical (EDC), which was used as an anti-miscarriage drug until the 1970s. Women who took DES, along with their daughters, have a higher risk of breast cancer.
• Air pollution – This contains carcinogens, EDCs and particulate matter, that is fine particles 10 micrometres or less in size, which may contribute to increased breast cancer risk.
• Studies have found low levels of vitamin D are linked to an increased breast cancer risk. The body produces adequate levels of vitamin D if the skin is exposed to sufficient sunlight. Other sources of vitamin D include diet or supplements. The main function of vitamin D is maintaining calcium levels. Vitamin D may help prevent breast cancer by reducing breast cell growth and the production of oestrogen in the body.
• Where you live – This affects your breast cancer risk. The highest rates of breast cancer occur in North and Western Europe, Australia, New Zealand, Canada and the US. The lowest rates are found in Eastern Asia and South America. In the UK and other countries, living in urban areas, as opposed to rural areas, is associated with an increased risk of breast cancer.

The main factors that influence your risk of developing breast cancer include being a woman and getting older. If you have breast cancer risk factors, talk with your doctor about ways you can lower your risk and about screening for breast cancer.

Can breast cancer be prevented?

There is no sure way to prevent breast cancer. But there are things you can do that might lower your risk, such as changing risk factors that are under your control such as lifestyle changes, quitting smoking, giving up alcohol, exercising more and losing weight to achieve a healthy weight. You can use the NHS body mass index (BMI) calculator to check if you are a healthy weight.

Studies have shown women who breastfeed are statistically less likely to develop breast cancer than those who do not. The reasons are not fully understood, but it could be because women do not ovulate as regularly while they are breastfeeding and oestrogen levels remain stable.

If you have an increased risk of developing breast cancer, treatment is available to reduce your risk. The two main treatments are surgery to remove the breasts – a mastectomy – or medicine.

By removing as much breast tissue as possible, a mastectomy can reduce your risk of breast cancer by up to 90%. Women with the BRCA1 gene fault can currently opt to have both breasts removed to reduce their cancer risk. However, like all operations, there is a risk of complications, and having your breasts removed can have a significant effect on your body image and sexual relationships.

There are three medicines available on the NHS for women who have an increased risk of breast cancer. These can reduce your risk of breast cancer while you’re taking them and possibly for several years afterwards.

They are:

• Tamoxifen – For women who either have or have not been through the menopause.
• Anastrozole – For women who have been through the menopause.
• Raloxifene – For women who have been through the menopause.

You can’t totally eliminate the possibility of getting breast cancer, but there is a lot you can do to reduce your risk, and in doing so, you will reduce your risk of many other health conditions too.

What are the stages of breast cancer?

Staging for breast cancer is very complex. The stage of a cancer tells you how big it is and how far it has spread. It helps your doctor decide which treatment you need. The number staging system for breast cancer divides breast cancers into four stages, from 1 to 4. Stage 1 is the earliest stage and stage 4 means the cancer has spread to another part of the body.

Stage 1 breast cancer means that the cancer is small and only in the breast tissue or it might be found in lymph nodes close to the breast. Stage 1A means that the cancer is 2cm or smaller and has not spread outside the breast. Stage 1B means that small areas of breast cancer cells are found in the lymph nodes close to the breast and that no tumour is found in the breast or the breast tumour is 2cm or smaller.

Stage 2 breast cancer means that the cancer is either in the breast or in the nearby lymph nodes or both. It is an early stage breast cancer. Stage 2 breast cancer has two groups: stage 2A and 2B. Stage 2A means one of the following: there is no tumour or a tumour 2cm or smaller in the breast and cancer cells are found in 1 to 3 lymph nodes in the armpit or in the lymph nodes near the breastbone; or the tumour is larger than 2cm but not larger than 5cm and there is no cancer in the lymph nodes.

Stage 2B means one of the following: the tumour is larger than 2cm but not larger than 5cm and there are small areas of cancer cells in the lymph nodes; the tumour is larger than 2cm but not larger than 5cm and the cancer has spread to 1 to 3 lymph nodes in the armpit or to the lymph nodes near the breastbone; or the tumour is larger than 5cm and hasn’t spread to the lymph nodes.

Stage 3 breast cancer means that the cancer has spread from the breast to lymph nodes close to the breast or to the skin of the breast or to the chest wall. It is also called locally advanced breast cancer.

Stage 3 breast cancer is divided into three groups:

• Stage 3A means one of the following: no tumour is seen in the breast or the tumour may be any size and cancer is found in 4 to 9 lymph glands under the arm or in the lymph glands near the breastbone; the tumour is larger than 5cm and small clusters of breast cancer cells are in the lymph nodes; or the tumour is more than 5cm and has spread into up to 3 lymph nodes in the armpit or to the lymph nodes near the breastbone.
• Stage 3B means the tumour has spread to the skin of the breast or the chest wall. The chest wall means the structures surrounding and protecting the lungs, such as the ribs, muscles, skin or connective tissues. The cancer has made the skin break down forming an ulcer, or has caused swelling. The cancer may have spread to up to 9 lymph nodes in the armpit or to the lymph nodes near the breastbone. Cancer that has spread to the skin of the breast might be an inflammatory breast cancer.
• Stage 3C means the tumour can be any size, or there may be no tumour. But there is cancer in the skin of the breast, causing swelling or an ulcer, and it has spread to the chest wall. It has also spread to one or more of the following structures: 10 or more lymph nodes in the armpit, lymph nodes above or below the collar bone, or lymph nodes in the armpit and near the breastbone.

Stage 4 breast cancer means that the cancer has spread to other parts of the body. It is also called secondary breast cancer, advanced cancer, or metastatic breast cancer. In stage 4 breast cancer, the tumour can be any size, the lymph nodes may or may not contain cancer cells, and the cancer has spread (metastasised) to other parts of the body such as the bones, lungs, liver or brain.

Can breast cancer be detected early?

Screening aims to find breast cancers early, when they have the best chance of being cured. Women with a higher-than-average risk of developing breast cancer may be offered screening and genetic testing for the condition.

Mammographic screening, where X-ray images of the breast are taken, is the most commonly available way of finding a change in your breast tissue at an early stage. A mammogram might fail to detect some breast cancers. It might also increase your chances of having extra tests and interventions, including surgery, even if you are not affected by breast cancer.

As the risk of breast cancer increases with age, all women in the UK who are aged between 50 to 70 years old are invited for breast cancer screening every 3 years. You will automatically get your first invite for breast screening between the ages of 50 and 53. Then you’ll be invited every 3 years until you turn 71.

If you are a transman, transwoman or are non-binary, you may be invited automatically, or you may need to talk to your GP surgery or call the local breast screening service to ask for an appointment. You need to be registered with a GP surgery to be invited for breast screening.

You should see your GP if you have any symptoms of breast cancer, even if you have recently had a clear breast screening. Do not wait for your next breast screening appointment.

Being breast aware means getting to know how your breasts normally look and feel. This may change at different times of the month. You don’t need to examine your breasts every day or even every week. But it is important to know how your breasts normally feel, and how that changes with your periods.

Some women have lumpier breasts around the time of a period. If this is the same in both breasts, don’t worry. But check your breasts again the following month, a few days after your period is over. If the lumpiness comes and goes with your menstrual cycle, it is nothing to worry about.

Your breasts usually feel softer and not as lumpy if you no longer have periods. If you have any breast changes and are worried that you might have cancer you should go to your GP.

How is breast cancer diagnosed?

A biopsy is the only definitive way to make a diagnosis of breast cancer. Biopsies can be taken in different ways, and the type you have will depend on what your doctor knows about your condition. During a biopsy, the doctor extracts a sample of cells from the suspicious area and it is tested to see if it is cancerous.

You may also need a scan and a needle test on lymph nodes in your armpit (axilla) to see whether these are also affected. A needle biopsy is the most common type of biopsy.

A sample of tissue is taken from a lump in your breast using a large needle. You may have a local anaesthetic, which means you’ll be awake during the procedure but your breast will be numb. Your doctor may suggest that you have a guided needle biopsy, usually guided by ultrasound or X-ray, or sometimes MRI, to obtain a more precise and reliable diagnosis of cancer.

A vacuum-assisted biopsy, also known as a mammotomy biopsy, is another type of biopsy. During the procedure, a needle is attached to a gentle suction tube which helps to obtain the sample and clear any bleeding from the area.

If a diagnosis of breast cancer is confirmed, more tests will be needed to determine the stage and grade of the cancer, and the best method of treatment.

How is breast cancer treated?

The main treatments for breast cancer are:

• Surgery – This is usually the first type of treatment for breast cancer. The type of surgery you have will depend on the type of breast cancer you have. There are two main types of breast cancer surgery: breast-conserving surgery, where the cancerous lump (tumour) is removed, or mastectomy, where the whole breast is removed.
• Radiotherapy – This uses controlled doses of radiation to kill cancer cells. It is usually given after surgery and chemotherapy to kill any remaining cancer cells.
• Chemotherapy – This involves using anti-cancer (cytotoxic) medicine to kill cancer cells. It is usually used after surgery to destroy any cancer cells that have not been removed. This is called adjuvant chemotherapy.
• Hormone therapy – Some breast cancers are stimulated to grow by the hormones oestrogen or progesterone, which are found naturally in your body. These are known as hormone receptor-positive cancers. Hormone therapy lowers the levels of oestrogen or progesterone hormones in your body or stops their effects. The type of hormone therapy you have will depend on the stage and grade of the cancer, which hormone it’s sensitive to, your age, whether you have experienced the menopause, and what other type of treatment you’re having. You will probably have hormone therapy after surgery and chemotherapy, but it’s sometimes given before surgery to shrink a tumour and make it easier to remove.
• Targeted therapies – These are medicines that change the way cells work and help to stop cancer from growing and spreading. Not all types of breast cancer can be treated with targeted therapies. The targeted therapy most commonly used to treat breast cancer is trastuzumab, also known by the brand name Herceptin. Some targeted therapies are given through a drip into a vein; others come as tablets.

You have regular check-ups after your treatment for breast cancer. This is to check how you are and see whether you have any problems or concerns. At each check-up your doctor or nurse checks how you are coping with any ongoing treatment, for example hormone therapy. After your treatment, you might have regular check-ups for at least 5 years. How long you have these will vary depending on your hospital or clinic.

Many women have no more problems after their original treatment for breast cancer. But sometimes breast cancer comes back. This is called a recurrence. The treatment you have for a local recurrence depends on the treatment you had before.

You might have one or more of these treatments, and it might include:

• Having the whole breast removed if you had breast-conserving surgery before.
• Radiotherapy.
• Chemotherapy.
• Hormone therapy.
• Targeted cancer drugs.
• Bone strengthening drugs.

Final thoughts

The following organisations can offer advice and practical support for people concerned about or living with breast cancer:

• NHS Choices – Information from the National Health Service on conditions, treatments, local services and healthy living.
• The Breast Cancer Haven is a UK charity supporting the physical and emotional needs of anyone affected by breast cancer.
• Breast Cancer Now – Patient support and helpline.
• Macmillan offer information, practical help and support for people living with cancer.
• Maggie’s offer support and help for people living with cancer. Maggie’s centres are located nationally alongside NHS hospitals or online.
• Flat Friends is a charity that supports ladies living without reconstruction after a mastectomy.
• Breast Cancer Genetics Hereditary Breast Cancer Helpline 01629 813000.