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2. What is breast cancer?

3.  What is breast cancer?

Answer: Cancer is a word that is used to describe about 200 different diseases affecting organs or systems of the body. Each type of cancer has its own possible causes, and develops and behaves in its own way. Breast cancer is explained here, with descriptions of the different types and what might cause them to occur.

3.1 Breast cancer

All cancers are diseases of cells. Cells are the smallest building blocks in our bodies, invisible to the naked eye. Groups of cells form the tissues and organs of the body (such as the breasts, liver or lungs) and each of these has a very specific function.

Very Important: Both women and men can develop breast cancer, although it is very rare in men.

Cells normally reproduce themselves by dividing in a regular, orderly fashion so that body tissues can grow and repair any damage. If this normal function is disrupted, there may be an uncontrolled growth of cells forming a lump called a tumor. There are two kinds of tumor, benign and malignant, and the malignant ones are called cancer. Most tumors in the breast are benign.

This means they remain contained within a localized area, cannot spread and often do not require any treatment as they do not do any harm. An example of a common benign breast tumor is a fibro adenoma (an overgrowth of normal tissue that forms a lump). Sometimes an operation is needed to remove a fibro adenoma because it is large or uncomfortable but in most cases such a lump can safely be left alone.

Malignant breast tumors (cancer) can also grow in the breast. These are different to benign tumors because they have developed, or can develop, the ability to spread either to surrounding tissue or elsewhere in the body.

This process is called metastasis. Breast cancer cells spread elsewhere by breaking off the original breast tumor and traveling in the bloodstream to distant sites in the body where they may form new tumors called metastases or secondaries. Cancer cells may also be carried away from the breast in the lymphatic system, which normally helps the body to fight infection. This system is made up of lymph nodes (glands) and vessels (tubes) linked throughout the body. The lymphatic system drains the fluid lymph from different parts of the body and returns it to the bloodstream.

Because breast cancer cells can spread to vital organs (such as the liver or lungs) and affect their normal function, secondary breast cancer anywhere in the body can be a life-threatening disease.

Both women and men can develop breast cancer, although it is very rare in men.

Question: Are there different types of breast cancer?

Answer: Yes. Most breast cancers are a type of cancer called carcinomas. These arise from the cells lining an organ or system. Within our breasts, there are lobules (where in women milk is made and stored) and ducts (tubes which carry milk to the nipple). Breast cancers that start in the lobules are called invasive lobular carcinoma and breast cancers that start in the ducts are called invasive ductal carcinoma.

There is also a very early type of breast cancer called ductal carcinoma in situ (DCIS). This is when cancer cells are found in the ducts but have not yet developed the ability to spread. It usually needs to be removed because in some cases the DCIS will go on to become invasive breast cancer and could therefore spread at some point in the future.

There are also other less common types of breast cancer such as inflammatory breast cancer, malignant phyllodes and Paget's disease.

Question: Do all types of breast cancer behave in the same way?

Answer: No. Different breast cancers behave in their own way and grow at different rates. Some are more likely to be treated successfully than others. We still don't fully understand why breast cancers can behave differently and why some respond better to treatment than others. Various sub-types and this may help predict a person's chances of survival and indicate how best to treat them.

Each sub-type of breast cancer is made up of different tissues because of the different proteins inside it. Sub-types identified so far include luminal and basal, but as there are breast cancers that don't yet fit in any sub-type, more research is needed.

Question: Why did my friend's breast cancer come back years after it was treated?

Answer: Breast cancers usually take many months or even years to grow to the size they are when they can be diagnosed. During this period there is plenty of time for cells to break off the original tumor and spread to other parts of the body (called secondary or metastatic breast cancer).

At the time of diagnosis, these secondary breast cancers may be too small to be detected. Even if all the original cancer seems to have been removed, or there is no evidence of cancer after treatment, the secondary breast cancers may already be growing at other sites.

They may stay 'silent' for months or years, just as the original cancer did, until the cells reach sufficient numbers to cause a new symptom. It only requires one breast cancer cell to be left undetected or untreated for the disease to recur in the future. This is what probably happened in your friend's case.

Secondary breast cancer cells spread to other parts of the body from the first, or primary, tumor in the breast through the lymphatic or blood system. When breast cancer spreads, for example to the bones, it is called secondary breast cancer in the bone. This is because the cancer cells in the bone are breast cancer cells.

If breast cancer comes back in either the same breast or near the mastectomy scar, it is called a local recurrence. When it spreads to areas around the breast such as the skin, the muscles on the chest wall, the lymph nodes under the sternum (breastbone), between the ribs or the nodes above the clavicle (collarbone) it is called regional recurrence.

Question: I see a lot about breast cancer in newspapers and magazines now, and more on television. Is breast cancer becoming more common?

Answer: Breast cancer is the most common cancer in the UK. How many people get a certain type of cancer each year is called the incidence and the incidence of breast cancer is increasing every year. There are several reasons for this. We all live longer nowadays which means there is more time for breast cancer to develop. We are also better at finding breast cancers now, specifically through the nationals screening programme in some European Union Member-states.

Finally there have been lifestyle changes in the population, in that we eat differently, drink more alcohol and more of us are overweight.

In the most developed countries of European Union in 2011 over 60,000 cases of breast cancer were diagnosed. More than 50,700 of these were in women, with just 300 cases in men.

Question: Is breast cancer the main cause of death in these countries?

Answer: Breast cancer is the second biggest cause of death from cancer in women in the UK for example (lung cancer is the biggest). But overall there are many more deaths in women, and men, caused by cardiovascular disease (heart attacks and strokes)

Question: I am nearly 45. What is my chance of getting breast cancer?

Answer: Across your whole lifetime your chance as a woman of getting breast cancer is one in nine, but this is cumulative, meaning that the risk increases as you get older. In younger women, the chances are much less. Up to the age of 30 you have only a one in 1,900 chance of getting breast cancer. Your individual risk of breast cancer can also be affected by the risk factors explained below.

Question: If I do get breast cancer I’ll probably die from it, won’t I?

 Answer: No, in fact most people are alive many years after a diagnosis of breast cancer. Survival figures for breast cancer are usually given in terms of five-year, ten-year and twenty-year survival, which is the percentage of people alive that many years after they were first diagnosed and treated. In the most developed countries of European Union, 80% are alive at five years after a diagnosis of primary breast cancer; at 10 years this is 72% and at 20 years the survival is 64%. Not everyone still alive at these time points will be cured; some may already have had a recurrence of their breast cancer and for some it may return later.

Question: What causes breast cancer?

 Answer: Every cell in the body contains a set of instructions (its genetic material) which controls the way it grows and behaves. Cancer happens when changes take place in this genetic material so that the cells no longer behave normally and instead grow in an uncontrolled way. There are many reasons why this may happen. In some cancers, the causes are much clearer (there is far more evidence), for example smoking and lung cancer, but with breast cancer a definite cause is harder to pinpoint. This is why health professionals will more commonly talk about risk factors, rather than causes. Risk factors are things that affect the chances of breast cancer developing in an individual person, either increasing or decreasing their risk.

Question: What are the main risk factors for breast cancer?

 Answer: The two biggest things that increase our risk of developing breast cancer are our sex and our age, neither of which we can do anything about. Just being a woman puts people at most risk because nearly all breast cancers occur in women. Getting older also increases the risk because most cases (over 80%) occur in women aged 50 years and over. Breast cancer is much less common in younger women. In men, where breast cancer is rarer, there are some known risk factors, for example:

• Increasing age (it is more common over 60 years of age);

• Radiation (for example, previous treatment for Hodgkin’s disease) but these accounts for a tiny number of cases;

• Obesity (being overweight);

• An inherited faulty gene (affecting less than 10% of breast cancers in women and 15% of all breast cancers in men);

• High oestrogen levels (for example, due to obesity or chronic liver damage);

• Klinefelter’s syndrome (an extra female chromosome, which is very rare)

Question: I started my periods rather late. Does that make a difference?

Answer: There is a slight increase in breast cancer risk the earlier a girl starts her periods and the later a woman begins the menopause.

This is because some breast cancers use the female hormone oestrogen to help them grow. There is more of this hormone circulating around the body after puberty and before the menopause.

The average age for starting your periods is around 13 years old but if they start earlier, this increases the amount of time that a woman is exposed to circulating hormones.

So, since you started late your risk may be lower than average. Similarly, most women go through the menopause at 50 or 51 years of age. If this happens later than average, say in their mid- to late fifties, it also slightly increases the risk of breast cancer.

Question: My wife believes that having had children and breastfeeding them protects her from breast cancer. Is she right?

Answer: She has the right idea. Having children and having them earlier in life (for example in your twenties) results in a lower risk of developing breast cancer than having children later or not at all, and the risk gets slightly less the more children a woman has.

Breastfeeding also reduces the risk of breast cancer but only by a little and only if done for a year or more – though not necessarily all at once: feeding two children for six months each would still count. Generally the longer a woman breastfeeds the more her risk of breast cancer reduces but it is still a very small reduction overall.

Question: I am having trouble with the menopause and thinking about HRT. But does it cause breast cancer?

 Answer: Taking HRT (hormone replacement therapy) for less than five years will have a negligible effect on your breast cancer risk. However, if you take it for longer than this your risk may increase. It also increases if it is combination HRT, containing oestrogen and progesterone rather than oestrogen only. This risk falls a few years after the HRT is stopped. It is a personal decision whether or not to take HRT. It is important to weigh the benefits to you, in reducing difficult menopausal symptoms, with your individual risks. Talk over the pros and cons with a doctor or practice nurse to help you reach an informed decision.

Question: I have heard that taking the contraceptive pill may cause breast cancer, so should I avoid it?

Answer: It used to be thought that taking the Pill did slightly increase the risk of breast cancer. Recent studies, however, have found no more women get breast cancer who has taken the Pill than those who have never taken it. Your choice of contraception has to be a personal matter, and you should talk over the advantages and disadvantages of each method with a doctor or practice nurse. That way you and your partner can make an informed decision.

Question: I have put on quite a lot of weight recently. Do weight and exercise really make a difference to the risk of breast cancer?

Answer: Being overweight does increase your risk of breast cancer, particularly after the menopause. It seems the more weight you put on over your lifetime, the higher the risk of breast cancer developing after menopause. There are also many other good reasons for keeping your weight within the normal range for your height, not least that it will reduce your risk of developing heart disease and diabetes. Taking regular exercise (at least 30 minutes a day, five times a week) also reduces the risk of breast cancer and as with weight gain, this seems even more important in reducing the risk in post-menopausal women.

Question: My partner and I enjoy a few drinks most evenings. Should I worry about alcohol and my risk of breast cancer?

Answer: The more a woman drinks the greater the risk of developing breast cancer. The risk increases very slightly with every extra unit of alcohol you drink each day, and more so with regular binge drinking. This doesn’t mean that you should give up alcohol altogether. The golden rule is to drink in moderation. Try to follow guidelines on the recommended safe amounts of alcohol: for women, no more than two units per day (one unit of alcohol is half a pint of beer or cider, one small glass of wine or a single measure of spirits).

Question: We have had quite a lot of cancer in our family. Can you inherit breast cancer?

 Answer: The vast majority of breast cancers happen by chance because it is a very common disease worldwide. However, in a very small number of cases (less than 10%) it can run in families, when it is called familial or hereditary breast cancer. Overall, less than one woman in 100 is at high risk of developing inherited breast cancer, which is passed on in a faulty gene. The genes we know most about are called BRCA1, BRCA2 and TP53. If the faulty genes are confirmed (or are extremely likely because of the patterns of affected relatives), the problem is hereditary. However, if there are several cases in the family, but no obvious pattern or confirmed gene mutation, we may call it familial. Not every family member will inherit the faulty gene because we all inherit two copies of each of our genes – one copy from our mother and one copy from our father. If your mother or father carries a faulty gene s/he will also have a normal copy. This means that you have a 50:50 chance of inheriting the faulty copy and a 50:50 chance of inheriting the normal copy. If you inherit the faulty copy you have a 50:50 chance of passing it on to your children. If you don’t inherit the faulty gene, you can’t pass it on to your children. We can begin to suspect the possibility of inherited breast cancer if there have been more relatives affected in one family than one would expect (multiple cases). Broadly speaking, people have a higher risk than average of developing breast cancer, which across a lifetime is one in nine, if they have any of the following in their family:

• A female first-degree relative (mother, daughter or sister) who developed breast cancer at a young age (under 40);

• Two first-degree relatives, or one first-degree and one second degree male or female relatives (grandparents, grandchildren, uncles, aunts, nieces, nephews) who both developed breast cancer under an average age of 50;

• A first-degree male relative (father, brother or son) who developed breast cancer at any age;

• A first-degree relative who developed breast cancer in both breasts (bilateral breast cancer), particularly if under 50 years of age;

• Three first- or second-degree relatives who developed breast cancer at younger than an average age of 60;

• Four or more relatives who developed breast cancer at any age.

If you are concerned about familial or hereditary breast cancer, the first step is to talk things over with your family doctor. Your doctor should ask about family history and ethnic background. This is because the chances of breast cancer being inherited are higher in some ethnic communities, such as Ashkenazi Jewish people. They will also want to know about any blood relatives who have had breast or related cancers (such as ovarian cancer that can be caused by the same faulty gene) and their age when the cancer developed. They then estimate the risk, and if it is considered moderate or high you will be referred for more specialist advice, for example to a cancer genetics centre. There, the staff will offer to take a detailed family tree to work out the risk. People at higher risk will be offered genetic counseling to help them understand their risk and all the implications to them and other family members.

Question: Can I be tested for a faulty gene?

 Answer: Yes, but only those in a high-risk group will be offered genetic testing. There are several steps to the testing process. First, a blood sample is taken; ideally from a living relative with breast cancer so that the exact fault on the gene can be identified. This can take many weeks, or even months. If no faulty gene is found, you will not need to be tested. This doesn’t mean that a fault does not exist, as it could be on a part of a gene that cannot be detected by current technology. If a faulty gene is found, the test can then be offered to other relatives who have not yet had breast cancer. This is because the genetics experts will know exactly what gene fault to look for in the other family members. An unaffected relative with the same gene fault is at high risk of developing breast cancer. Family members without the gene fault and who are not affected by breast cancer will be at no more risk than anyone else in the population, and neither will their children. Remember, though, that even a person at high risk will not necessarily develop breast cancer.

Question: Do all women or men who carry a faulty gene get breast cancer?

Answer: No, carrying a faulty BRCA 1 or BRCA 2 gene gives, at most, up to around an 80% chance of developing breast cancer across the lifetime, so it is never certain.

With BRCA1 the lifetime risk of breast cancer for women by age 70 is up to 80% (the risk declines significantly with age) and there is a 12–60% lifetime risk of ovarian cancer.

With BRCA2 the lifetime risk of breast cancer for women by age 70 is up to 80% but the risk does not decline significantly with age and there is a 10–27% lifetime risk of ovarian cancer. With BRCA2 there is also a greater risk for men to be affected. Breast cancer in men is much rarer but when it does develop about 15% will be hereditary (compared to just 5% in women). If men do inherit a faulty gene their lifetime risk of developing breast cancer is under 10% (compared to 40–80% in women with a faulty gene).

Question: I have been told my risk is higher than average. What are my options?

Answer: The action most guaranteed to drastically reduce risk is a bilateral risk-reducing mastectomy (having both breasts removed). This is a serious undertaking, and any woman considering it must usually have a faulty gene confirmed or at least be at high risk (usually three times the risk in the general population). Counseling and information would be offered to help you decide whether to go ahead with this operation.

Alternatively, women at high risk can have screening by mammogram (breast X-ray) or a magnetic imaging scan (MRI) regularly. This is usually annually up to the age of 50; then they join the national breast screening programme available in many countries, but they will continue to be screened each year. Men, even those at high risk, are not routinely offered screening but it is available. There are also trials offering hormone therapies such as tamoxifen and anastrozole (Arimidex®) to women at high risk. Women taking these as a treatment for breast cancer have far fewer new primary breast cancers in the other breast. This suggests these drugs can reduce the chances of breast cancer occurring and so might be useful for women with an increased likelihood of developing the disease. However, they also cause side effects so once again you need to discuss this with the professionals so you can make an informed decision.

Question: Will changing my diet reduce my risk of getting breast cancer?

Answer: It is not possible to give a simple answer, as some changes might make a small difference to breast cancer risk, while others will not affect it at all. Studies on diet and risk rely on people accurately recording what they have eaten, so it is hard to determine what exactly in the diet affects risk. There is, however, convincing evidence that breast cancer risk is slightly increased by:

• A high total dietary fat intake, especially saturated fat (found in meat and dairy products);

• High consumption of red meat (only in older women and those who eat red meat at least once every day).

There is no convincing evidence that eating too many dairy products or white meat or too little fruit, vegetables, fiber and phytooestrogens (plant based oestrogens such as soya) will increase breast cancer risk. But there is also no evidence to the contrary. However, eating a well-balanced, healthy diet is recommended to reduce the risk of other illnesses, such as heart disease and diabetes, and to help keep your weight within normal limits (for your height).

Question: There is a lot written about ‘super foods’. Is there anything I should eat?

 Answer: There is no one definition of a ‘super food’ but generally they refer to foods that are rich in vitamins, antioxidants and omega-3 oils. Antioxidants protect our bodies against free radicals, which play a role in ageing and tissue damage that might lead to cancer. They are found mainly in fruit and vegetables. However, whilst fruit and vegetables are important for a healthy diet and have potential anticancer properties, there is no evidence that they offer any protection against breast cancer. Omega-3 oils are part of a healthy diet and help reduce the risk of heart disease. They are found mainly in oily fish and we should eat one or two portions of oily fish a week. Vegetarian sources include linseed and hemp seed. However, as with antioxidants, there is no evidence that they offer any protection against breast cancer.

Question: Does soy help protect against breast cancer?

Answer: The number of women getting breast cancer in Asia and Japan is lower than in the Western world and a lot of people claim this is because these women eat more soy. Soy is a phyto-oestrogen (a natural, plant-based oestrogen) and it is thought that phytooestrogens contain anti-cancer properties. However, there is no evidence that soy has any effect on breast cancer risk.

Question: Should I only eat organic food because additives cause breast cancer?

Answer: Many people believe that breast cancer is linked to additives in our food. But studies have failed to find any link, and no studies have been done which compare organic and non-organic foods to see their effects on breast cancer development. The safety of food additives and food colourings is governed by the European Food Safety Authority which checks the safety of food additives and makes recommendations about safe quantities and types of additives.

Question: My husband thinks I should take lots of vitamins to protect myself against breast cancer. Will they help?

Answer: The only vitamin for which there is some, although not conclusive, evidence is vitamin D. Making sure you have enough vitamin D will very slightly decrease your chances of getting breast cancer. You can get this from sunlight exposure (just a few minutes a day) and foods such as oily fish, eggs and cereals. Other vitamins are unlikely to have any effect on breast cancer risk. If you eat a well-balanced, healthy diet you should get enough vitamins naturally and not need to take supplements.

Question: Does smoking cause breast cancer?

Answer: I am thinking of giving up. We would advise you to give up anyway. Researchers have not agreed about this because some studies have found a slight increase in breast cancer risk among smokers, while others have not. It seems from some studies that any risk might be increased in women who start smoking during their teens. Although we cannot be certain about smoking and breast cancer risk, there is no doubt that smoking is a major cause of lung cancer and heart disease, as well as increasing the risk of cancer of the larynx (voice box) and oesophagus (gullet). Everyone is strongly advised not to smoke but, if you do, seek help to give up.

Question: I have read that underarm deodorants cause breast cancer. Is this true?

Answer: Probably not, because there is no convincing evidence to support this – and lots of logical reasons why it is unlikely. Stories have claimed that anti-perspirants and deodorants stop the body from getting rid of toxins (poisons) in sweat and that these toxins could cause breast cancer. But the liver is the main organ used in removing unwanted toxins from the body, whereas the main reason for sweating is to cool the body down. Also, if this were true, we would expect to see more cases of cancer in both breasts, because people use deodorants under both arms, and more breast cancer in men.

Question: I heard a rumour that wearing an underwired bra can mean you will get breast cancer. Should I stop wearing one?

Answer: There is no convincing evidence to support this theory and you can safely choose to wear any style of bra – just make sure it fits you well, so that your breasts feel comfortable. A poorly fitting bra can be the cause of breast pain; it’s a good idea to be measured once a year. I carry heavy boxes at work and am always accidentally knocking myself.

Question: Will bumps and bruises make me more likely to get breast cancer?

Answer: There is no reason to think that this sort of injury will lead to cancer. However, you might want to talk to your line manager about health and safety at work!

Question: I was thinking about having breast implants to make me bigger but then heard that they will increase my risk of breast cancer. Will they?

Answer: Breast implants do not affect the risk of cancer developing. However, they can occasionally make it harder for the breasts to be looked at properly on a mammogram (breast X-ray). This can be solved by taking the mammogram pictures from a different angle.

Question: You hear that having an abortion makes breast cancer more likely. Is this true?

Answer: There was a study some years ago which seemed to indicate this but more recent studies have shown that having an abortion does not in any way affect the risk of breast cancer.

Question: How do I know if I am at more risk of breast cancer because of where I work?

Answer: It is quite normal to worry about whether environmental factors, such as where you work, will affect your chances of getting breast cancer. There has been a lot of research into links between breast cancer and chemicals in our environment such as pesticides and parabens. However, it is hard to isolate individual chemicals rather than any other factor as the cause of any harmful changes. There is no convincing evidence at present to support this theory and more research is needed. You should, of course, wear all the recommended protective clothing offered to you at work and follow all the procedures laid down by your employer. If you want to discuss this further, talk to the occupational health department, works doctor, safety representative or your employer.

Question: Can you catch breast cancer from someone else?

 Answer: No. Breast cancer is definitely not infectious or contagious like flu or measles.

Question: I have heard that you can develop breast cancer a few months after a really stressful time. Is this true?

Answer: If it were true, it would be hard to prove. We all deal with stress in our own way, and it is very difficult to measure. What one person finds stressful may be exhilarating for someone else. Currently, there is no concrete evidence that stress plays any direct part in the development of breast cancer, but nor is there absolute evidence that it does not. Common sense and experience suggest that we find it hard to deal with all kinds of challenges when we are low. We can be sure that stress which leads us to eat badly, for example too much fat, or drink too much alcohol for any length of time, may influence our breast cancer risk.

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