Breast Cancer and Oestrogen
Around 60 per cent of breast cancers are sensitive to the female sex hormone oestrogen. The growth of these cancers can be minimised by taking drugs that block the action of oestrogen in the breast tissue.
Breast cancer affects one in 12 Australian women, with around 2,600 Victorians diagnosed as having the disease every year. There are different types of breast cancer. Around 60 per cent are sensitive to the female sex hormone oestrogen. These cancers are called receptor positive cancers. Paradoxically, breast cancer is more common in postmenopausal women, whose oestrogen levels have dropped to the point where ovulation is no longer possible. It seems that oestrogen is also made inside breast tissue. Medications such as tamoxifen can block the action of oestrogen and prevent it from stimulating the breast cancer cells.
Breast cancer and women of childbearing age
Menstruating women who have hormone responsive breast cancer can benefit from hormone therapy. Interest in oestrogen and its link to breast cancer was first sparked when it was noticed that a side effect of chemotherapy - stalled menstrual cycle - happened to improve a woman's chances of recovery. Research is now looking at the effects of blocking oestrogen in young women to starve their breast cancers. For example, luteinising hormone releasing hormone (LHRH) can be used to plummet oestrogen to postmenopausal levels. The menstrual cycle recovers after the end of treatment. Hormone therapy may be combined with chemotherapy. Each person should make a decision about whether or not to have chemotherapy in consultation with their doctor. The decision should be made after all available information on the benefits and risks has been fully discussed.
Oestrogen in the postmenopausal woman
Breast tissue contains fat cells. These cells make an enzyme called aromatase, that produces oestrogen. In normal breast tissue, the amount of aromatase is carefully regulated. As a woman ages, the fat cells of her breasts tend to produce greater and greater amounts of aromatase, which in turn increases the amount of local oestrogen. This seems to play a role in triggering breast cancer in postmenopausal women. Once established, the tumour further increases oestrogen levels, which helps it to grow. Immune cells that flock to the tumour also seem to boost oestrogen production.
Hormone therapy
After surgery to remove the hormone responsive tumour, drugs such as tamoxifen can be used to block the action of oestrogen and lower the risk of recurrence. Current research
is focusing on newer compounds designed to block oestrogen production in the breast only, as oestrogen is still needed for - amongst other things - healthy bones. Possible side effects of tamoxifen include:
· Hot flushes
· Reduced appetite
· Stomach upsets
· Dizzy spells
· Leg cramps
· Respiratory problems
· Increased risk of blood clots
· Slight increased risk of cancer of the lining of the uterus.
Breast cancer and hormone replacement therapy
Menopause can trigger unpleasant side effects such as hot flushes and vaginal dryness. Hormone replacement therapy (HRT) eases the symptoms by boosting sex hormone levels. It also reduces the risk of osteoporosis and heart disease. However, since some breast cancers depend on oestrogen, women taking HRT for a long time (more than five years) have an increased breast cancer risk of around 30 per cent. Women who undergo HRT for shorter periods of time (such as two years) have the same risk of breast cancer as women who haven't used HRT. The health benefits of HRT are considered to outweigh the risks in most cases.
Where to get help
· Your doctor
· Cancer Council Victoria Information and Support Service Tel. 131 120
Things to remember
· Around 60 per cent of breast cancers are sensitive to the female sex hormone oestrogen.
· The growth of cancer can be minimised by taking drugs that block the action of oestrogen in the breasts.
· Side effects of hormone therapy include dizzy spells, hot flushes and respiratory problems.
Breast cancer affects one in 12 Australian women. Around 2,600 Victorian women are diagnosed with the disease every year. It is most common in women over the age of 50 years. While it is extremely rare, men can also develop breast cancer.
There are different types of breast cancer. Most breast cancers start in the milk ducts, which are small tubes designed to take the milk from the milk sacs(lobes or lobules) to the nipple. Some cancers start in the milk sacs. Cancer cells can break off from the main cancer and spread to other parts of the body, such as the bones and liver, via the lymph nodes situated in the armpits.
Contributing factors
The exact cause of breast cancer remains unknown, but there seem to be contributing factors that increase risk. Some established risk factors include:
· Gender - the strongest risk factor for breast cancer is being a woman.
· Advancing age - breast cancer incidence increases with age. The majority of cases occur in women over 50.
· Heredity - a strong family history of the disease. The increase in risk depends on the number of relatives affected, the age of the relative(s) when they developed breast cancer, and whether they were on one or both sides of the family.
· Previous history of breast cancer - women who have had breast cancer in one breast have a greater risk of developing it in the other breast.
· Benign breast disease - some types of breast disease seem to indicate an increased risk of breast cancer.
Other risk factors
More research needs to be done before we can be definite about risk factors. However, there are a number of other possible risk factors including:
· Not having children, or having children after the age of 30
· Early age at menarche (first period)
· Later age of natural menopause (55 years or older)
· Increased alcohol intake
· Obesity or substantial increase in body size after menopause
· The pill
· Hormone replacement therapy (HRT).
Changes in the breast
Breasts undergo changes during a woman's life. Changes may be related to puberty, the menstrual cycle, pregnancy, breastfeeding, changes in weight or ageing. It is important for all women to get to know the normal look and feel of their breasts. By regularly checking their breasts, women may be able to recognise changes that could be a sign of breast cancer. Such changes include:
· Thickening of the tissue
· A lump or lumpy area
· Discharge from the nipple
· An inverted or turned-in nipple
· Puckering or dimpling of the skin
· A change in shape
· Pain
· Anything that is not 'usual'.
Any unusual breast changes such as these need to be checked by a doctor. It is important to remember that nine out of 10 breast changes are not breast cancer.
Examination and diagnosis
Breast changes are investigated through a series of tests, which may be organised by your doctor or specialist. Initial tests include:
· Physical examination - breasts and armpits are examined.
· Diagnostic mammogram - an x-ray of the breast tissue.
· Ultrasound - a device that uses sound waves to scan the breast.
If further tests are required, one or more of the following procedures may be used:
· Fine needle aspiration - a very narrow needle is used to withdraw cells from the area for testing.
· Core biopsy - a larger needle is used to take a tissue sample for testing.
· Open biopsy - surgery performed under general anaesthetic to remove the whole area for testing.
· Hormone tests - if a cancer is found, it can be checked for special markers called hormone receptors to see if it will respond to hormone treatment.
· Other tests - such as blood tests, bone scans and chest x-rays can be used to see if the cancer has spread, via the lymphatic system, to other sites of the body.
Most breast changes are diagnosed as benign. If cancer is detected, your doctor will advise you of the treatment options.
Treatment options
Treatment depends on different factors, including:
· The type of cancer
· The size of the cancer
· Whether or not the cancer has spread to other sites in the body
· Your age
· Your general health
· Your personal preferences.
Surgery is usually the first treatment
An operation to remove the cancer, surrounding breast tissue, and often the nearby lymph nodes, is the preferred first treatment. Possible side effects of surgery include infection, nerve damage and swelling of the arm. Surgery options include:
· Mastectomy - the entire breast is removed, along with lymph nodes from the armpit. Extra cancer treatment is often unnecessary.
· Breast-conserving surgery - a smaller operation removes the cancer, some of the surrounding tissue and usually some lymph nodes, leaving the bulk of the breast intact.
Other treatments
Depending on the cancer, other treatment options can include:
· Radiotherapy - using x-rays (radiation) to kill any remaining cancer cells. Women who have had breast-conserving surgery often have a course of radiotherapy. Side effects can include a reddening of the skin, which looks like sunburn.
· Chemotherapy - cancer-killing drugs that are given intravenously. Chemotherapy can be offered to women with early breast cancer as an extra treatment to surgery, radiotherapy or both. Side effects can include nausea, vomiting and hair loss.
· Hormone treatments - many breast cancers are influenced by the sex hormones oestrogen and progesterone. Hormone treatment can reduce the chances of breast cancer developing again.
Breast forms and reconstruction
Breast forms or prostheses are pads that are worn inside your bra. They help to restore balance and are designed to look like a normal breast under clothes. Some women choose to have a breast reconstruction, either at the time of the mastectomy or later. Options include saline-filled implants, or the use of your own muscle and skin to create a breast-like shape.
Where to get help
· Your doctor
· Specialist
· Surgeon
· Breast cancer support groups
· The Cancer Council Victoria's Cancer Information and Support Service Tel. 131 120
Things to remember
· Breast cancer affects one in 12 Australian women.
· It is important for all women to get to know the normal look and feel of their breasts.
· Although most breast changes aren't caused by breast cancer, you should always consult your doctor if you notice an 'unusual' change.
Treatment options for breast cancer include surgery, radiotherapy, chemotherapy and hormone treatment. Breast cancer is a major health issue for women. Statistics show that one in 11 women in Australia will develop breast cancer, and over 2,500 will die from it every year. More Australian women die of breast cancer than any other form of cancer. In recognising the devastating effects of breast cancer for women, health ministers in the Commonwealth, States and Territories agreed in 1990 to jointly fund a national mammography screening program. The National Program for the Early Detection of Breast Cancer, now BreastScreen Australia, was established in 1991 and is now recognised as one of the most comprehensive population-based screening programs in the world.
Free mammograms
Screening mammography is carried out in an organised and systematic manner to detect unsuspected cancer at an early stage. This is important, as early treatment can reduce illness and death from breast cancer. This population-based approach is distinctly different from the use of mammography to investigate symptoms in an individual woman, which is a diagnostic procedure. The program provides free screening mammograms at two-year intervals, mainly for women aged between 50 and 69 years. In doing so, the program aims to achieve significant reductions in the death and illness of women attributable to breast cancer.
Screening and assessment
All services for detecting and diagnosing breast cancer are provided, from the initial mammogram to any follow-up procedures needed. All BreastScreen services have the same basic structure: each has an assessment centre and one or more screening units. The initial mammogram is done in the screening unit. If a woman needs further investigation, she is recalled to the assessment centre, where the abnormality is assessed by a multidisciplinary team.
Accreditation process ensures high standards
The effectiveness of BreastScreen Australia depends on maintaining high standards in all areas of program delivery. All services have to meet the minimum standards set by national accreditation requirements, which have been developed by professionals involved with the program. The National Accreditation Standards (NAS), previously known as the National Accreditation Requirements, have been redeveloped in conjunction with a wide range of stakeholders. Victoria's network of eight assessment centres and 40 screening sites, including a mobile van, have all gained full accreditation. The accreditation process means that women can be confident that the standards of mammography screening meet the national standards, no matter where they attend. In conjunction with the national accreditation process, the collection of data in the program is also vital.
Where to get help
· Your doctor BreastScreen Australia Tel. 132 050
Things to remember
· BreastScreen Australia offers free mammograms at two-year intervals to women aged between 50 and 69 years.
BreastScreen Australia is recognised as one of the most comprehensive population-based screening programs in the world. A breast x-ray or mammogram is the best way to detect breast cancer in its earliest stages among women over 50 years of age. Early detection can improve the chances of successful treatment and recovery. Breast x-ray screening aims to show changes which are too small to be felt by you or your doctor and which cannot be found in any other way. Screening is normally recommended once every two years.
The risk increases with age
While all women are at risk of developing breast cancer, it is far more common as we grow older. Screening mammograms are most effective for women aged over 50 years. This is because the breast tissue in younger women is more dense, and can make a mammogram difficult to read. If you are over 50, BreastScreen Victoria will send a letter to remind you when your next visit is due.
If you are aged 40 to 49 years, you can have a screening mammogram at BreastScreen if you request it, but you will not be re-invited until you are 50. If you have had breast cancer in the past, talk over screening options with your specialist, as the screening program may not be suitable for you.
Preparing for your mammogram
Some suggestions to prepare for your mammogram include:
· Wear separates such as a top and a skirt, since you'll have to undress from the waist up.
· If you are still having periods, book your appointment for mid-cycle when your breasts may be less tender.
Having your mammogram
A health worker will greet you and explain what happens. Feel free to ask any questions. The radiographer will position your breasts one at a time between two flat plates on the x-ray machine. The x-ray uses a very low dose of radiation and the procedure takes only a few minutes. It may feel uncomfortable because each breast is held quite firmly while the x-ray is taken. If it feels painful, tell the radiographer.
The results
A mammogram can find most cancers that are present at the time of the x-ray, but like many other medical tests, it is not 100 per cent accurate. Most women will be pleased to find there are no signs of cancer. If your x-rays show any change in your breast tissue, you may be called back to have more x-rays and further tests. Most women called back do not have cancer.
Where to get help
· Your doctor
· Women's health centre
· BreastScreen Victoria - Tel. 132 050
Things to remember
· The risk of developing breast cancer increases with age.
· Breast x-rays or mammograms are the best way to detect cancer in its earliest stages among women over 50 years.
A mammogram every two years is recommended. Most changes in breast tissue are not cancer.
For many years it was believed that genes were the major factor in a person's risk of developing cancer. However, new evidence suggests that environmental factors - such as tobacco, diet, infection, alcohol, drugs, chemicals and radiation - may play a larger role than once thought. Sometimes it seems that genetics is the reason, especially when certain types of cancers run in families, but it's really not clear whether shared genes or a shared environment is to blame.
Twins and genetic research
Studying identical and non-identical twins is the ideal way, at this stage, to separate genetic factors from environmental factors when looking at the development of disease. Identical twins share the exact same genes, while non-identical twins share around half. If, for example, a disease is caused by genetic factors alone, then it could be assumed that identical twins will develop the disease in the same part of their body at around the same time. Therefore, if genes play a significant role in cancer, then cancer rates should be higher among identical twins.
Swedish study looks at 44,000 pairs of twins
Paul Lichtenstein and colleagues from the Karolinska Institute in Sweden studied more than 44,000 pairs of identical twins from Denmark, Finland and Sweden. Their findings were recently published in the New England Journal of Medicine. They compared rates of stomach, colorectal, pancreatic, lung, breast, cervical, uterine, ovarian, prostate and bladder cancers, as well as leukemia.
Lichtenstein's study found more than 10,000 cancers among their group of more than 90,000 people. By calculating the incidence of the same cancer in both twins, the researchers were able to roughly estimate the role of genetic factors. Generally, if one of the pair developed cancer, the odds of the other twin developing the same cancer were less than 15 per cent. This means that, based on the results of this study, environment has the greatest influence on the development of cancer.
Cancers with a strong genetic component
According to Lichtenstein's research, cancers that seem to be influenced the most by genes (estimated percentage of genetic contribution shown) include:
· Prostate cancer - 42 per cent
· Colorectal cancers - 35 per cent
· Stomach cancer - 28 per cent
· Breast cancer - 27 per cent
· Lung cancer - 26 per cent.
The research, however, did not explore specific types and degrees of exposure to environmental factors, such as cigarette smoking or diet. This means that the interaction between genes and environment in the development of cancer was not fully explored.
The conclusions
While genetics may mean that some people are more vulnerable to cancer than others, environmental factors determine which of these people will develop the disease. This major study of cancer rates in twins supports the current belief that most cancers are caused by environmental factors, such as diet and smoking. However, the high rates of genetic influence in some cancers, such as prostate cancer, indicate that more research is needed.
Where to get help
· Your doctor.
Things to remember
· Comparing cancer rates between twins helps to distinguish between the influence of genetic and environmental factors.
· Latest research supports the current ideology that most cancers are caused by environmental rather than genetic factors.
· The cancers with the highest genetic contribution include prostate, colorectal, stomach, breast and lung cancers.
Cancers are the second most common cause of death in Victoria; they account for around 8,000 deaths every year. Cancer is not one disease but many, including lung, breast, colon, skin, cervical and prostate cancer. Some cancers can be prevented by avoiding risk factors; for others, early detection is the best way to improve the odds of survival.
The age factor
Most cancers increase in frequency with age. Cancer is becoming more common in Victoria because of our ageing population. The most commonly diagnosed cancers are prostate cancer (for men) and breast cancer (for women).
Different death rates
Death rates from cancers vary between different population groups. Some of these variations include:
· Socioeconomic differences - lung cancer is more common in lower socioeconomic groups, while breast cancer is more common in higher socioeconomic groups.
· Geographic differences - the male death rate from lung cancer is 25 per cent higher in provincial cities than the overall Victorian rate.
· Birthplace differences - people born overseas have lower death rates from cancer; (except lung cancer); this is probably due to lifestyle and diet.
Screening can help in some cancers
A person with cancer may not show any symptoms until the disease is advanced. This means that apparently healthy people might be harbouring sub-clinical cancers. Mass screening is a growing trend and is used if:
· The disease can be recognised at an early stage.
· There is a specific, low risk and low cost screening test.
· Early treatment is likely to give a better outcome.
· The disease is a burden on the public health system.
Different cancers explained
Individual cancers differ in their causes, onset, treatment and outcome. They include:
· Lung cancer - largely caused by cigarette smoking. Since the outcome is poor, the best way to reduce the impact of this cancer is prevention.
· Breast cancer - risk factors include a family history of the disease, increased body weight, and not having had children or a late age for first pregnancy. The Victorian mammographic screening program targets women aged 50 to 69 years.
· Colon and rectal cancer - risk factors include a family history of the disease and a low fibre, high fat diet. Screening options include genetic testing, faecal testing and colonoscopy. A national bowel cancer screening pilot program is testing the feasibility of providing the general population with acceptable and
· affordable bowel cancer screening, which ultimately reduces mortality and morbidity from bowel cancer.
· Melanoma - skin cancer is more common in Australia than any other country. The incidence is highest in the 30 to 45 age group. Most melanomas are treatable if detected early.
· Cancer of the cervix - risk factors seem to be a higher number of sexual partners and smoking. Most cancers can be detected early with regular Pap smears.
· Prostate cancer - this is the most common cancer for men. A risk factor is a family history of the disease. There are no reliable screening tests.
Where to get help
· Your doctor.
Things to remember
· Cancer is not one disease but many.
· Cancers differ in their Some cancers are easily detected and treated; for others, prevention is best.cause, onset, treatment and outcome.
