The female breast contains 15–20 lobes, each of which is packed with milk-producing glands called lobules. In lactating women, milk is transported along tiny tubes, or ducts, to the nipple. Breast cancer can start in the ducts (where it is known as ductal carcinoma) or in the lobules (where it is known as lobular carcinoma). At its earliest, non-invasive stage the cancer remains ‘in situ’ within its original tissue (e.g. ductal carcinoma in situ, or DCIS). A cancer that starts in one area and spreads to surrounding tissue is known as an infiltrating or invasive carcinoma.
The breast also contains lymph vessels that form part of a network of tubes throughout the body known as the lymphatic system. Lymph is a fluid that carries infection-fighting cells, part of the body’s immune system, and carries away waste products. Individual vessels join together in lymph nodes. The nodes nearest to the breast are in the armpit, and are known as axillary nodes. The lymphatic system is important in breast cancer as it allows individual cancer cells that have broken away (metastasised) from the tumour to be transported via the lymph fluid from the breast to other parts of the body.
The human body is made up of individual units called cells and the cells in turn form the organs such as the heart and lungs. Throughout life, all cells grow and divide to produce more cells as and when the body needs them. This process is governed by DNA, the genetic material present in every cell, which is made up of small packets of information called genes, which tell the cell when to grow, divide, or die. Sometimes a gene becomes abnormal, or mutates, and the cell containing this faulty gene then grows and multiplies out of control to eventually form a mass of cells called a tumour.
The specific causes of breast cancer are not yet fully understood, but certain women seem to be at a higher risk of developing the disease than others. From studying women with breast cancer, scientists have pinpointed numerous factors that increase the risk of developing breast cancer; some can be controlled, while others are unchangeable (see below).
Factors that cannot be changed
- Age – More than 80% of breast cancers occur in women aged 50 years and over.
- Gender – Being a woman is the most important risk factor; less than 1% of breast cancers occur in men.
- Genes – Certain genetic mutations increase breast cancer risk, including BRCA1 and BRCA2.
- Family history – Having a mother, sister, or daughter with breast cancer increases a woman’s risk.
- Personal history – A woman with cancer in one breast has a higher risk of developing cancer in the other breast or another part of the same breast.
- Race – White women have a slightly higher risk of developing breast cancer than black or Asian women.
- Menstruation/Menopause – Women who started their periods before age 13 or went through menopause after age 50 are at increased risk.
Factors that can be changed
- Pregnancy/Breastfeeding – Women who have a baby before age 30, those who have many children, and women who breastfeed are at lower risk of breast cancer.
- Oral contraceptives – Long-term use of birth control pills may slightly increase breast cancer risk.
- Hormone replacement therapy – Using combination HRT (oestrogen plus progesterone) for more than 5 years increases the risk of breast cancer.
- Weight – Obesity may increase the risk of breast cancer, especially after the menopause.
- Alcohol – Regularly drinking more than 2 units of alcohol per day raises breast cancer risk.
- Radiation – Women exposed to high levels of radiation, particularly in the chest area (e.g. as radiation treatment for other cancers in childhood) are at increased risk.
- Exercise – Although still controversial, many studies have suggested that exercise may protect against breast cancer.
- Whilst the above factors can be useful indicators, approximately half of all women who develop breast cancer have no identifiable risk factors other than being female and aging.
In the majority of women, breast cancer is first noticed as a lump in their in the breast. All women’s breasts can develop some degree of ‘lumpiness’ at times and it is important to remember that only a small percentage of lumps are malignant, 8 out of 10 lumps are benign and not cancerous.
However, not all breast cancers present as a lump and there are other signs to be aware of, including:
- Breast lump, swelling, or pain.
- Lump or mass in the armpit.
- Nipple pain or discharge.
- Redness, scales, puckering, or dimples of the nipple or breast.
- Inversion of the nipple.
- Accentuated veins on breast surface.
- Any change in breast size or shape.
A doctor should be consulted right away if any of these signs and symptoms are noticed, however, in most cases such changes will not be cancerous.
Mammography is an X-ray technique for examining the breast. It is especially useful for detecting early changes in the breast tissue when it might be difficult to feel a lump.
Many of the industrialised countries have adopted national mammographic screening programmes to examine women of certain age groups, usually 50 to 69 years, at regular intervals. Since the introduction of such a programme in the UK, a significant decrease in mortality in this age group has been observed, thought to be due in part to the earlier detection achieved by screening.
BreastCancerSource.com
http://www.breastcancersource.com
Europa Donna
http://www.cancerworld.org
Cancer BACUP
http://www.cancerbacup.org.uk/Home
Cancer Research UK
http://www.cancerresearchuk.org
Breast Cancer Care
http://www.breastcancercare.org.uk/Home
National Breast Cancer Coalition
http://www.natlbcc.org
Breast Cancer Research
http://breast-cancer-research.com
Breast Cancer Action
http://www.bcaction.org
Further Reading:
Val Sampson and Debbie Fenlon
The Breast Cancer Book
Vermilion, London 2000
ISBN 0-09-185613-2
Michael Baum et al.
Breast Cancer: a guide for every woman
Oxford University press 1994
ISBN 0-10-262436-9
Hilary Thomas Karol Sikora
Cancer: a positive approach
Thorsons 1995
ISBN 0-7225-3132-X
Jeffrey Tobias
Cancer: what every patient needs to know
Bloomsbury 1995
ISBN 0-7475-1993-5