What is Breast Cancer?
A woman’s breasts are made of specialised tissues supplied by blood vessels, lymph nodes and nerves. Breast cancer is the uncontrolled growth of cells in the breast. This mass of abnormal tissue is called a tumour. Breast cancer can develop in both men and women, although female breast cancer is more common.
Types of Breast Cancer
Non-invasive breast cancers
Non-invasive breast cancers are cancers that are contained within the milk ducts or lobules in the breast. They have not grown into, or invaded, the normal breast tissue. Non-invasive cancers are called carcinoma in situ and are sometimes referred to as pre-cancers.
Ductal carcinoma in situ
Ductal carcinoma in situ (DCIS) is the most common type of non-invasive breast cancer. It starts in the milk ducts of the breast and is non-invasive because it hasn't spread into any surrounding breast tissue. DCIS isn't life-threatening, but having DCIS can increase the risk of developing an invasive breast cancer later in life.
Lobular carcinoma in situ
Lobular carcinoma in situ (LCIS) is non-invasive breast cancer that grows in the lobules (the milk-producing glands at the end of breast ducts). It is non-invasive as it has not spread into any surrounding breast tissue. LCIS isn't life-threatening, but having LCIS can increase the risk of developing invasive breast cancer later on in life.
Invasive breast cancers
Invasive cancers are cancers that are growing in the normal, healthy breast tissue.
Early breast cancer
Early breast cancer is cancer that is contained within the breast. It may also have spread to lymph nodes in the breast or armpit.
Paget's disease of the nipple
Paget's disease of the nipple is a rare form of invasive breast cancer in which cancer cells grow in the nipple or the areola (the area around the nipple). The nipple and areola often become scaly, red, itchy, and irritated.
Inflammatory breast cancer
Inflammatory breast cancer is a rare and aggressive form of invasive breast cancer that affects the blood vessels in the skin of the breast. It usually starts with the breast becoming red and inflamed, rather than with a lump.
Locally advanced breast cancer
Locally advanced breast cancer is an invasive breast cancer that is large or has spread beyond the breast to other nearby areas. Locally advanced breast cancer usually has a combination of some or all of the following features:
- Larger than 5 centimetres
- spread to other tissues around the breast such as the skin, chest wall or muscle
- spread extensively to lymph nodes
Hormone receptor positive breast cancer
About two-thirds of breast cancers are hormone receptor positive, which means that they need female hormones (oestrogen and/or progesterone) to grow and reproduce. Most people with hormone positive breast cancer will be recommended hormone therapy. These are oral medications that are taken daily for at least five years following the completion of other breast cancer treatments (surgery, chemotherapy and/or radiotherapy).
HER2-positive breast cancer
HER2-positive breast cancer is a breast cancer that tests positive for a protein called human epidermal growth factor receptor 2 (HER2). The cancer cells make an excess of HER2, which promotes the growth of cancer cells.
The drug Herceptin specifically targets HER2-positive breast cancer and has been proven to be a very effective treatment.
Triple negative breast cancer
If you have triple negative breast cancer, this means that your cancer does not have any of the three receptors commonly found on breast cancer cells (oestrogen, progesterone and HER2). Around 15% of breast cancers are triple negative. These generally respond very well to chemotherapy.
Metastatic breast cancer
Metastatic breast cancer, also known as advanced, secondary or stage 4 breast cancer, is breast cancer that has spread to more distant parts of the body such as the bones, liver or lungs.
Metastatic breast cancer is when cancer cells have spread from the original cancer site in the breast to more distant parts of the body. Terms such as advanced breast cancer, secondary breast cancer, secondary cancers, metastases and secondaries are all different ways of describing metastatic breast cancer, but they all mean the same thing.
Fortunately, advances in treatment mean that many women with metastatic breast cancer are now living for many years.
Metastatic breast cancer is breast cancer that has spread beyond the breast to other organs in the body, most often the bones, lungs, liver or, less commonly, brain. There are many words used, but they actually mean the same thing.
Metastatic breast cancer is also called:
- stage IV (4) breast cancer
- secondary breast cancer
- advanced breast cancer
When referring to a specific area or site of metastatic breast cancer, the term secondary is often used - for example a secondary in the bone.
The word metastases is sometimes also used to describe these sites, e.g. bone metastases. The original cancer in the breast is referred to as the primary.
Although metastatic breast cancer has spread to another part of the body, it is considered and treated as breast cancer. For example, breast cancer that has spread to the bones is still breast cancer (not bone cancer) and is treated with breast cancer drugs, rather than treatments for a cancer that began in the bones.
Risk Factors of Breast Cancer
Cancer occurs due to mutations or changes in the genes responsible for regulating the normal growth of cells and keeping them in a healthy condition. These mutated genes may be inherited from parents, or may result from external influences of radiation or cancer-causing chemicals, or wear and tear during the ageing process. Hormones also play a major role in the development of breast cancer.
Factors that could increase the risk of developing breast cancer
- Being a woman
- Family or previous history of breast cancer
- A history of ADH, DCIS or LCIS
- BRCA 1 or 2 positive
- Dense breast tissue
- Early menstruation (before age 12) and late menopause (after age 55)
- Use of birth control pills
- Use of HRT
- Heavy smoking and alcohol consumption
- Being overweight or obese
- Not breastfeeding after child birth
What are the Stages of Breast Cancer?
Staging is the process of finding how much the cancer has spread in the body. The staging process determines the stage of the cancer which is the most important factor in determining the person’s prognosis and appropriate treatment options. Staging describes the extent or severity of a cancer and whether or not it has spread to the lymph nodes or distant organs.
Some common elements found in most staging systems are the location of the primary (original) tumour, size of tumour, number of tumours, lymph node involvement, cell type, grade of tumour and presence or absence of metastasis (the spread of cancer).
Staging is based on the results of the physical examination, imaging tests (X-rays, CT or MRI scan and PET scan), laboratory tests of blood, urine, other fluids, biopsy of tissues, and the results of surgery. A staging system is a way to describe the spread and extent of a cancer.
TNM Staging System
The most common cancer staging system being used is the TNM (extent of the tumour, spread to lymph nodes, distant metastases) system. Breast cancer is divided into different stages based on how far the cancer cells have spread beyond the site of the original tumour.
- Stage 0:
- Cancer cells in breast duct
- Have not invaded into other normal tissues
- Stage IA:
- Tumour measures up to 2 cm
- Has not spread
- No lymph nodes are involved
- Stage IB:
- No tumour or tumour of 2 cm in breast tissue
- Developing cancer cells in the lymph nodes measuring 0.2 to 2 mm
- Stage IIA: One of the below cases
- No tumour in breast, but cancer cells in lymph nodes under the arm (axillary lymph nodes)
- Tumour of 2 cm has spread to the surrounding axillary lymph nodes
- Tumour of 2 to 5 cm but has not spread to the surrounding axillary lymph nodes
- Stage IIB: One of the below cases
- Tumour of 2 to 5 cm has spread to the surrounding axillary lymph nodes
- Tumour of 2 to 5 cm but has not spread to the surrounding axillary lymph nodes
- Stage IIIA: Tumour may (of any size) or may not be present in breast. Cancer has spread to the lymph nodes near the breast bone or under the arm (axillary lymph nodes).
- Stage IIIB: Cancer has spread to the chest wall and the skin of the breast and the lymph nodes near the breast bone or under the arm.
- Stage IIIC: Cancer has spread to the chest wall and skin of the breast and the lymph nodes above and below the collar bone, near the breast bone or under the arm.
- Stage IV: Cancer has spread to various other parts of the body.
Summary Staging System
Summary staging is also the most commonly used system of staging for all types of cancer.
Summary staging groups cancer into five main categories:
- In situ: It is an early cancer that is present only in the layer of cells in which it developed.
- Localised: A localised cancer is a cancer limited to the organ in which it started, without evidence of spread.
- Regional: A regional cancer is a cancer that has spread beyond the primary tumour location to distant organs or sites.
- Distant: Distant cancer is a cancer that has spread from the primary site to nearby lymph nodes or organs.
- Unknown: There is not enough information to indicate a stage.
Symptoms of Breast Cancer
Initially, breast cancer may or may not cause any symptoms. The first sign of cancer is commonly a lump or mass in the breast. The lump is usually painless and hard, with an uneven edge, but may be tender and soft at times. Any unusual signs such as swelling of the breast, skin irritation, pain in the breast or nipple, nipple turning inwards, redness or thickening of nipple or breast skin, nipple discharge, or lump in the underarm area may indicate breast cancer.
Diagnosis of Breast Cancer
Breast self-examination is a primary way to detect breast cancer at its early stages. This includes feeling for lumps and looking for abnormal symptoms in the breasts. Other diagnostic tests may be performed if you are suspected of having breast cancer. Some of these tests include:
- Mammography: A skilled technician places and compresses your breast between 2 plates attached to a highly-specialised camera. The camera takes 2 pictures of the breast from different directions. The breast is compressed to reduce its thickness to obtain a clear X-ray image.
- Ultrasound scan: High frequency sound waves are emitted onto your breast and converted into images of the breast tissue.
- Biopsy: A small sample of breast tissue is removed from the area of concern and examined under a microscope to ascertain whether it is cancerous tissue and to determine the characteristics of the cancerous tissue.
- Blood test
The early detection of cancer makes treatment easier and more successful.
Treatment of Breast Cancer
Your doctor will plan your treatment based on the stage of cancer. Treatment will not only target and destroy the cancer cells, but also endeavour to ensure that it does not recur. Your doctor may follow a sequence of treatments including:
- Surgery: Your doctor may choose between many types of surgeries. These include the removal of the tumour and a small margin of healthy tissue, the entire breast tissue and sometimes, even the neighbouring lymph nodes. After the removal, your breast can also be reconstructed in an immediate or later procedure.
- Chemotherapy: This treatment includes the administration of medicine through the bloodstream to weaken and destroy the cancer cells in the body. Chemotherapy may be given after surgery, to kill any cancer cells that have been left behind in the body or before surgery, to shrink the cancer.
- Radiation therapy: In this therapy, high-energy radiations are used to destroy cancer cells. This is a highly targeted and effective way to destroy breast cancer cells. This therapy is easy to tolerate and the side effects are limited to only the treated area. It also prevents the recurrence of breast cancer.
- Hormonal therapy: This therapy includes treating breast cancer with hormones. These medications help to shrink or slow the growth of cancer cells by lowering the levels or blocking the action of the oestrogen hormone on the cancer cells.