An overview of the breast ageing process
Breasts are made up of various types of tissue, including glandular, fatty and connective tissues1. The composition of these tissues changes as part of the ageing process, triggered by declining oestrogen levels during perimenopause and menopause, which causes the glandular portion of breast tissue to shrink. Specifically, the milk ducts that carry milk to the nipples as part of breastfeeding and lactation shrink, and this causes a corresponding decrease in breast density, firmness and fullness2. This tissue is replaced with more fatty tissue, which is responsible for the breasts losing their elasticity and becoming softer as you age2.
These changes in breast composition also alter the cells that make up breast tissue, leading to lumps and bumps – many of which are benign and non-cancerous. It’s important to keep in mind that lumps and bumps become easier to feel once breasts lose their firmness, and they don’t always indicate cancer2.
However, changes to the cellular makeup of the breasts can increase the risk of developing breast cancer. This is why breast cancer is predominantly an age-related illness, with studies finding that more than 80% of breast cancers occur after the age of 502.
Understanding the connection between breast cancer and ageing
Fatty tissue has the potential to produce hormones and growth factors that can trigger inflammation and cell proliferation (an increase in cell numbers), which can promote uncontrolled cell growth. These are key processes involved in the development of breast diseases, including breast cancer2. So, as the proportion of fatty tissue of the body increases, we see a corresponding increase in the incidence of cancer including breast cancer.
On top of this, immune cells in the breast and blood change as part of the ageing process, and this also contributes to breast cancer development. For instance, our protective immunity deteriorates and leads to increased immunosuppression, which means the body’s immune cells (responsible for neutralising threats such as infections and abnormal cancerous cells) are less robust at fighting off cancer cells. Meanwhile, we also experience reduced immune surveillance, meaning the immune system is less attuned to detecting abnormal cells2.
In essence, the changes that occur within the breast create an environment where cells are more likely to grow in an uncontrolled way, and there is an increased risk that these cells evade detection by our body’s immune system – therefore increasing the susceptibility to breast cancer.
Breast density explained – why does it matter?
While breast density generally decreases with age, more than half of women under 50 still have dense breasts, along with 40% of women in their 50s3,4. People with dense breasts have more fibroglandular tissue (made up of fatty tissue, dense fibrous tissue and glandular tissue)1, and this difference has been found to increase breast cancer risk5. As well as this, the greater the breast density, the harder it can be to see cancers on a mammogram. This is because fibroglandular tissue and cancers both appear white on a mammogram6.
Having dense breasts is more likely if you have a lower body mass index (BMI) or you are taking hormone replacement therapy. However, it's worth noting that breast density is not related to how breasts look or feel – nor to their size. It also cannot be assessed by a physical examination, but rather a mammogram only 6.
It’s crucial to recognise that increased breast density does not mean that a person will develop breast cancer – it simply indicates that the risk is higher. For this reason, breast density should be considered alongside other breast cancer risk factors, including age and family history6. You can read about these in this article.
Most BreastScreen services do not advise people of their mammographic density. At present, only residents of South Australia and Western Australia are informed if a BreastScreen mammogram reveals increased breast density3. However, some BreastScreen state programs, such as BreastScreen Victoria, are in the early stages of a state-wide roll-out of breast density reporting, with results letters expected by early 2025.
In the meantime, don't be afraid to ask your doctor about your breast density as this can help you make informed decisions about your health.
Navigating breast changes throughout life
Breast lumps are more common with age, and these lumps become easier to feel as breast firmness reduces. In most instances, they are non-cancerous, but it’s important to have any new or unusual symptoms checked out by your GP.
Importantly, remaining up to date with routine breast screening, breast self-examinations and yearly health checks with your GP can help detect early signs of a health condition.
You can also rest easy knowing that Zurich is here to support you with its services, including the free My Wellbeing Hub, along with Zurich Evolve and a range of life insurance plans. Wherever you may be in your journey, we’re committed to helping you stay healthy and feel healthier.
