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BREAST CANCER STAGES

Learn more about the different stages of breast cancer.

What are Breast Cancer Stages and how are they different from Types?

A breast cancer diagnosis will be categorised into a stage, which is determined by the cancer’s characteristics such as how large it is, if it has spread to other tissue inside the breast or has spread to other parts of the body.

The type of breast cancer is determined by a tissue sample and helps to determine what treatment you should receive. It is a descriptor of where the breast cancer originated, your cancer’s pathology, if you cancer is fuelled by hormones and the genetic makeup of your tumour.

Your doctor will consider your breast cancer type and stage when planning your treatment.

A breast cancer can be described as being stage 0 to stage 4, with the prognosis becoming increasingly negative as the number increases.

Stage 0: Stage 0 is sometimes used to describe non-invasive breast cancers such as DCIS. In this stage, there is no evidence of cancer invading into the surrounding breast tissue. It has been diagnosed early and remained in the breast ducts or milk glands.

Stage 1: A stage one breast cancer means the cancer is less than 20mm in size and has not spread to nearby lymph nodes.

Stage 2: The cancer has grown to more than 20mm in size and/or spread to nearby lymph nodes.

Stage 3: The cancer is more advanced and is harder to treat. The cancer has not spread to the bones or organs but is larger and can be found in more lymph nodes and/or invasion of the chest wall or skin around the breast.

Stage 4: The breast cancer can now be found in other parts of the body, having spread through lymphatic channels or bloodstream, from the breast and lymph nodes. The most common sites are bones, lungs, liver, and brain. The cancer is now considered metastatic or advanced.

A breast cancer diagnosis can also be described as:

Local – Cancer is confined within the breast

Regional – The lymph nodes, primarily in the armpit, are involved

Distant – Cancer is found in other parts of the body, having spread beyond the breast.

More commonly, a breast cancer diagnosis is described as either early-stage, locally advanced or metastatic:

Early-Stage Breast Cancer

Early breast cancer is an invasive breast cancer that is contained in the breast and may or may not have spread to the lymph nodes in the breast or armpit. The aim of treatment for early breast cancer is to remove the breast cancer and any cancer cells that may be life in the breast, armpit, or other parts of the body, but cannot be detected. Treatment can involve radiotherapy, breast surgery, chemotherapy, hormonal therapies, and targeted therapies. The goal of treatment is to eradicate all cancer cells.

Locally Advanced Breast Cancer

Locally advanced breast cancer is an invasive breast cancer that is large or has spread to areas near the breast, such as the chest wall. However, there are no signs the cancer has spread beyond the breast region or to other parts of the body. The goal of treatment is to eradicate all cancer cells, however this is more difficult and the prognosis is not as good as early stage breast cancer.;

Signs of locally advanced breast cancer can include a lump in the breast or armpit that doesn’t move freely but feels attached to the chest wall, a lump at the base of the neck, ulcers on the breast, dimpled skin that looks like an orange peel or a large red, swollen breast. Treatment for locally advanced breast cancer will usually involve a combination of breast surgery, chemotherapy, radiotherapy, targeted therapies, or hormonal therapies.

Metastatic Breast Cancer

Metastatic breast cancer, also known as advanced, secondary, or stage four breast cancer, is a breast cancer which has spread to other parts of the body such as the bones, liver, or lungs. Many people who are diagnosed with metastatic breast cancer have been diagnosed with breast cancer before. However, for some it can be the first diagnosis of breast cancer.

Metastatic breast cancer occurs when cancer cells break away from the cancer in the breast and move through the blood vessels or lymphatic vessels and form a new cancer growth in other parts of the body.

Every metastatic breast cancer diagnosis is different and will therefore require different treatments. Despite the cancer growths being in other organs such as the lung, it is called ‘breast cancer’ and is treated as breast cancer. The aim of treating metastatic breast cancer is to control the growth and spread of the cancer, to relieve symptoms and improve or maintain quality of life. Treatment options will depend on what is most likely to control the cancer and what side effects the patient can cope with. Treatment for metastatic breast cancer can include hormonal therapy, chemotherapy, targeted therapy, radiotherapy, and surgery.

How Common is Breast Cancer?

Breast Cancer today inAustralia and New Zealand

Breast Cancer today In Australia

In Australia, the risk of a woman being diagnosed with breast cancer by the age of 85 is

1 IN 7

.. for men 1 in 670

… and New Zealand

In New Zealand, the risk of a woman being diagnosed with breast cancer in their lifetime is

1 IN 9

Breast Cancer Risk Factors

A risk factor is something about a person, or what that person is exposed to, that increases their ‘risk’ (in other words, the chance or likelihood) of developing breast cancer in future. This might be something about their genetic makeup that cannot be changed, or a lifestyle factor like alcohol of lack of exercise. But risk factors don’t tell us everything. Having a risk factor, or even several risk factors, does not mean a woman will definitely be diagnosed with breast cancer and many who are diagnosed do not have any known risk factors.

There is currently no way to definitively prevent breast cancer. However, you can assess your risk factors and their impact on your cancer risk using the iPrevent tool. Some risk factors can be modified, others cannot, and these may include:

  • Age

    The risk of breast cancer increases with age, with about 79% of all new breast cancer diagnosed in women aged 50 and over. The average age of first breast cancer diagnosis in Australia is 61 years.

    Besides gender, aging is the most significant risk factor associated with breast cancer [4]. The older you get, the more your cells accumulate DNA damage (mutations) and are therefore more likely to progress to cancer. According to Cancer Australia, women who are 50 years old are approximately 10 times more likely to develop breast cancer compared to women who are 30 years old.

  • Alcohol

    Alcohol consumption is associated with an approximate 30-50% increased risk in breast cancer risk [1]. Alcohol consumption is the most-established dietary risk factor of breast cancer thought to be due to the increase of endogenous oestrogen levels it causes [2]. 

    Your relative risk of breast cancer is increased by 7% of each additional 10 grams, or one standard drink, of alcohol consumed per day [3]. One standard drink is equivalent to 100mL of wine, 285mL full strength beer, 425mL low strength beer or 30mL (one nip) of spirits.

    Evidence shows there is no safe level of alcohol consumption in regard to breast cancer risk. A large meta-analysis of 222 articles finding even light drinking (up to one drink per day) increases the risk of breast cancer in women. The risk increases further with each extra drink.

  • Family History

    A family history of breast cancer means having one or more blood relatives who have received a breast cancer diagnosis.

    Studies have found that women with one first-degree relative with breast cancer have almost two times the risk of developing breast cancer compared to a woman without any affected relatives. Furthermore, this becomes a three times higher risk for women with two or more first-degree relatives with breast cancer [5]

    Approximately 5-10% of breast cancers are due to a strong family history (two or more close relatives) of genetic mutation such as BRCA1 or BRCA2. There are also lesser known gene-mutations linked to a higher breast cancer risk such as TP53, PTEN, CDH1 and STK11 and some rare moderate-risk gene mutations such as PALB2, ATM and CHEK2. Some women with strong family histories receive genetic testing to see if they have one of these mutations. You can learn more about genetic testing in this Breast Cancer Trials podcast.

    You can learn more about the genetic risks for developing breast cancer here.

    Breast Cancer Trials currently has a breast cancer prevention trial for those with the BRCA1 gene mutation. You can learn more here.

  • Dense Breasts

    Even though breast density is a lower risk than other risk factors such as family history, it is more common in the general population [6]. Mammographic density, or dense breasts, refers to the percentage of dense tissue of an entire breast and can be seen as the whiteness on your mammogram. Breast density cannot be felt or touched and can only be determined through x ray or mammograms.

    Women with dense breasts face two challenges; a potential late diagnosis of breast cancer due to poor sensitivity of mammographic screening and having a higher risk for developing breast cancer [7]. Researchers are uncertain as to why having dense breasts increases your breast cancer risks, but believe it has some genetic links. It is hypothesized that the greater proportion of epithelial and non-epithelial cells in areas of high breast density, and the greater cumulative exposure to hormones and growth factors, may stimulate more cell division which increases breast cancer risk [8].

    Breast density is just one risk factor and doesn’t mean you will be diagnosed with breast cancer. However, if you are aware of your mammographic density, you should talk with your doctor about regular screening. You can learn more about dense breasts in this podcast.

  • Being Overweight

    Being overweight or obese is a known breast cancer risk factor. Obesity is associated with a 20% to 40% increased risk of breast cancer in post-menopausal women. In patients diagnosed with breast cancer, obesity is associated with a 33% increased risk of cancer recurrence and of death from any cause [9].

    Additionally, gaining weight as an adult is associated with an increased risk of post-menopausal breast cancer. The risk increases by about 6% for each 5 kg increase in a woman’s weight.

    However, having a higher BMI before menopause is associated with a decreased risk of premenopausal breast cancer. For each 5-unit increase in BMI, the risk of premenopausal breast cancer is decreased by about 7% [10]. Importantly, obesity throughout life increases the risk of many other diseases such as heart disease and other cancers, leading to a higher rate of premature death.

    You should aim to lead an active life-style, with the Australian Government guidelines recommending 150 to 300 minutes (2 ½ to 5 hours) of moderate intensity physical activity or 75 to 150 minutes (1 ¼ to 2 ½ hours) of vigorous intensity physical activity, or an equivalent combination of both moderate and vigorous activities, each week if aged between 18-64. For those aged 65 and older, the recommendation is to be physically active for 30 minutes every day. This should be balanced with a healthy diet full of nutritious wholefoods [11].

  • Previous Radiation

    Previous exposure to radiation is a known breast cancer risk factor, which increased according to how much radiation you have been exposed to and when you were exposed. Age is an important factor, with females exposed before age 20 years having the highest risk and minimal risk for those exposed to radiation after menopause [12].

    Usually, this exposure to radiation therapy for young people in the chest region is due to treatment for Hodgkin lymphoma or childhood cancers. Women who were treated for hodgkin lymphoma using radiation alone have about five times the risk of breast cancer as women who did not receive this treatment. The risk is higher for those treated at a younger age, particularly close to the age when periods started [13].

  • Smoking

    Researchers have found an increased risk of breast cancer for those who smoke, particularly among women who started smoking at adolescence or younger ages. The relative risk of breast cancer associated with smoking has been found to be greater for women with a family history of the disease [14]

    The carcinogenic potential of tobacco smoke is unarguable and has been definitively linked to heart disease, lung cancer and many other cancers, therefore not smoking is the best choice for your health.

It’s important to know your personal breast cancer risk and manage any risks that can be changed, such as smoking, diet and exercise. Regular screening is important for those in the targeted age group of 50 – 74. If you are younger and concerned about your breast cancer risk, speak with your GP about your screening options.

Breast Cancer Signs and Symptoms

In the early stages of breast cancer there may be no symptoms at all. As the cancer grows, symptoms can include:

  • A new lump in the breast, armpit area or around the collarbone.
  • A change in breast size or shape.
  • Changes to the nipple, such as sores or crusting, an ulcer or inverted nipple.
  • Clear or bloody nipple discharge.
  • Changes to the skin including redness, puckering or dimpling (an ‘orange peel’ appearance).
  • Breast tenderness or pain.

Breast Cancer Symptoms

Sources:

The Australian Institute of Health and Welfare
Cancer Australia
New Zealand Breast Cancer Foundation

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