Breast Cancer

Note: The information on cancer types on the ACRF website is not designed to provide medical or professional advice and is for information only. If you have any health problems or questions please consult your doctor.

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  • What is breast cancer?

    In patients with Breast Cancer, abnormal cells develop in the breast and form tumours which invade the surrounding breast tissue.

    Breast cancer can occur in both males and females, though male breast cancer accounts for less than 1% of all breast cancer cases.


  • How does breast cancer develop?

    Breast cancer develops when cells in the breast grow in an abnormal way and form tumours.

    The female breast is comprised of milk-producing glands called lobules, ducts which carry milk from the lobules to the nipples, and fatty and connective tissue.

    Most cases of breast cancer begin in the cells that line the ducts, while others can begin in the cells that line the lobules.

    When cancer is confined to either the ducts or lobules, it is classed as non-invasive. If it spreads, it is referred to as invasive breast cancer.

  • How does breast cancer spread?

    Breast cancer spreads when tumour cells break away from the mass and travel via the bloodstream or lymphatic system to other tissues in the body, where they start multiplying again. This process is called metastasis.

    The location where cancer develops is known as the primary site. Cancer that forms as a result of spreading from the breast is referred to as metastatic, secondary or advanced breast cancer.

  • Types of breast cancer

    Breast cancer can occur in the:

    • Ducts of the breast (ductal carcinoma in situ or DCIS) or
    • Lobes of the breast (lobular carcinoma in situ or LCIS).

    When breast cancer is detected early, it is usually confined to the breast and may not have spread. It’s not always possible to detect whether cancer cells have spread.

    Advanced breast cancer is invasive (aggressive) breast cancer that may have spread either locally or to other parts of the body. In rare cases, advanced breast cancer can affect the lymphatic vessels in the skin of the breast.

    Infrequently, breast cancer can affect the nipple and areola, though this is often a secondary cancer associated with invasive breast cancer elsewhere in the breast.

  • Stages of breast cancer

    Once breast cancer has been diagnosed, certain tests will be performed to find out whether the cancer cells have spread within the breast or to other parts of the body.

    Cancer can spread through the breast tissue, through the lymph system and also by getting into the blood stream and traveling to other parts of the body.

    Tests used to determine how far the cancer has spread may include:

    • A biopsy of the first lymph node to which the cancer is likely to spread (known as the sentinel lymph node),
    • X-rays or CT scans
    • A bone scan to measure rapidly dividing cells within the bone
    • A PET (Positron Emission Tomography) scan to locate malignant tumour cells around the body.

    The information gathered from the staging test/s will determine how far the cancer has spread, and the most effective treatment plan can be determined

    Stage o breast cancer

    Stage 0 is known as ‘carcinoma in situ’ and there are three types of breast carcinoma in situ. The first type is ‘ductal carcinoma in situ’ (DCIS), a non-invasive type of breast cancer in which abnormal cells are found only in the lining of a breast duct and have not spread.

    The second type is called ‘lobular carcinoma in situ’ (LCIS) where abnormal cells are found only in the lobules of the breast.

    The third type of carcinoma in situ cancer is called ‘Paget disease of the nipple’ where abnormal cells are found in the nipple only.

    Stage 1 breast cancer

    If diagnosed with stage 1 breast cancer this will mean cancerous cells have formed a mass within the breast. Stage I is divided into two sub-stages: IA and IB.

    In stage IA, the tumour is 2cm or smaller and the cancer has not spread outside the breast.

    In stage IB, small clusters of breast cancer cells are found in the lymph nodes and there is either no tumour found in the breast – or the tumour within the breast is less than 2 cm in width.

    Stage 2 breast cancer

    Stage 2A
    In patients with stage 2A, either no tumour will be found in the breast or the tumour is smaller than 2cm. Additionally, the cancer will have been found in several axillary lymph nodes (a lymph node in the armpit region) or it has been found in the lymph nodes near the breastbone.

    Stage 2A can also mean the tumour is between 2cm and 5cm in size, and it has not spread to the lymph nodes.

    Stage 2B
    Stage 2B may mean the tumour is between 2cm and 5cm in size, with small clusters of breast cancer cells have been found in the lymph nodes. Additionally, Stage 2B could refer to a tumour that is between 2cm and 5cm and the cancer has reached up to three axilliary lymph nodes or the lymph nodes near the breastbone.

    A patient who has been diagnosed with a breast tumour larger than 5cm, but the cancer has not spread to the lymph nodes, will also be at Stage 2B.

    Stage 3 breast cancer

    Stage 3A
    In this stage, the tumour found is larger than 5cm and cancer has spread into up to three axillary lymph nodes or lymph nodes near the breastbone. The breast cancer will also be deemed ‘Stage IIIA’ if the cancer has spread to four to nine axillary lymph nodes or is present in the lymph nodes near the breastbone. In this latter scenario, there may or may not be a tumour in the breast.

    Finally this stage can also indicate that a tumour larger than 5cm has been found with only small clusters of breast cancer cells in the lymph nodes.

    Stage 3B
    In stage 3B, the breast cancer tumour may be any size, with cancer cells found in the chest wall and/or nearby the skin of the breast, causing swelling or an ulcer. This may also be Inflammatory Breast Cancer.

    At this stage, the cancer may have spread to up to nine axillary lymph nodes or the lymph nodes near the breast bone.

    Stage 3C
    Breast cancer at Stage 3C may have spread to the skin of the breast and caused swelling or an ulcer and/or spread to the chest wall. There will not necessarily be a tumour mass within the breast.

    Alternatively, the cancer may have spread to the axillary lymph nodes, the lymph nodes above or below the collarbone, or axillary lymph nodes and lymph nodes near the breastbone.

  • Breast cancer signs and symptoms

    A sign is a presentation that can be noticed – for example, a lump in the breast which can be discovered with a breast check. A symptom is a feeling such as pain or tenderness.

    Some breast cancers are detected before they lead to signs and symptoms, while other types of breast cancers can’t be detected with mammograms.

    How does breast cancer produce signs and symptoms?

    Breast cancer, which begins when cells grow abnormally and the form tumours in the breast, can cause different types of signs and symptoms.

    Signs and symptoms of breast cancer vary depending on the size and location of the tumour – as well as the speed at which it is growing.

    Diagnostic tests and procedures for breast cancer include physical examination, mammogram, biopsy, ultrasound and breast MRI (magnetic resonance imaging) scan. Blood tests and other scans may be ordered if signs and symptoms suggest the cancer may have spread outside of the breast area.

    What are the common general signs and symptoms of breast cancer?

    It should be noted that many breast cancer signs and symptoms are also associated with other diseases and conditions and may not necessarily indicate breast cancer.

    The most common sign of breast cancer is a lump or mass in the breast. This can be hard or soft, with or without accompanying pain. Not all lumps in the breast are cancerous, so if a lump is detected it’s important for patients to visit their doctor for a proper diagnosis.

    Other common signs of breast cancer include:

    • A rash around the nipples
    • Discharge from one or both nipples
    • Skin that has started to peel or flake
    • Nipple retraction
    • Pain or swelling in the armpits or breast area.

    Masses can also be detected under the arm or around the collarbone if the breast cancer has spread to lymph nodes. This may happen before the mass in the breast can be felt.

    If patients are experiencing any breast cancer signs and symptoms, or if they suspect something is not quite right, they should visit their doctor.

  • Breast cancer treatment

    Treatment depends on the stage and severity of breast cancer. Other factors, such as signs and patient health, may also impact the treatment approach.

    Common forms of breast cancer treatment include surgery to remove part or all of the affected breast, surgery to remove one or more lymph nodes from the armpit, radiation therapy and chemotherapy.

    An emerging body of research is indicating that knowing a tumour’s genomic profile could be more important for successful treatment than knowing its location or size. As each tumour’s genomic profile is unique, this approach is often referred to as personalised or precision medicine.

    How is breast cancer diagnosed?

    The recommended approach for investigating breast symptoms is the ‘triple test’.

    What is the triple test?

    The triple test includes the following steps:

    • Clinical breast examination
    • Imaging tests: mammogram, ultrasound or MRI. The test used depends on the woman’s age and breast density.
    • Biopsy: if either of the first two tests indicates an abnormal area, cells or tissue will be taken from that area and sent to a pathologist

    The earlier breast cancer is detected, the more likely it is that treatment can successfully remove the cancer and prevent it from recurring.

  • Breast cancer risk and prevention

    Breast cancer is the most common cancer among women, with nearly 1.7 million new cases diagnosed in 2012.

    Breast cancer risk

    While the specific causes of breast cancer are not yet known, scientists have identified a series of risk factors that may increase the chance of cancerous cells forming in the breast.

    Inherited gene mutations and acquired gene mutations are thought to be two of these risk factors. Inherited gene mutations, such as the BRCA genes (BRCA1 and BRCA2), are genes that suppress tumour growth. Many women with these mutated genes have a higher probability to develop cancer, though the genes don’t actually cause the cancer.

    Acquired gene mutations may occur in the breast as a result of factors like chemical or radiation exposure.

    Other risk factors for breast cancer can include being female, increasing in age, a family history of breast cancer, a personal history of breast cancer, hormonal factors and lifestyle factors.

    Breast cancer prevention

    Screening, early detection, increased awareness and constantly improving treatments are helping to gradually improve breast cancer survival rates.

    Raising awareness of the well-established breast cancer risk factors, encouraging patients to learn their family history, and referring at-risk patients for regular screening checks risk are all important preventative measures.

Breast cancer statistics

  • 20,640

    new cases are estimated to be diagnosed in 2022

  • 91.8%

    is the five-year survival rate for breast cancer

  • 62.9

    years is the median age of breast cancer diagnosis

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Cancer in Australia 2017, Australian Institute of Health and Welfare

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