Breast cancer is the abnormal growth of cells in the breast. These cells grow and develop into a cancerous growth that can have the potential to spread to other parts of the body.
Breast cancer is the abnormal growth of cells in the breast. These cells grow and develop into a cancerous growth that can have the potential to spread to other parts of the body.
In 2019, more than 3,300 New Zealand women and 25 New Zealand men were estimated to be diagnosed with breast cancer.1 Breast cancer will affect one in nine New Zealand women over their lifetime.1
There are many different types of breast cancer, some of which are common, while others are very rare. Some of these include:
Following a breast cancer diagnosis, further testing is then conducted to identify the receptor status of the cancer. Cancers will be classified as hormone receptor positive or negative depending on whether they have the proteins oestrogen or progesterone receptors on the surface. Your breast cancer may be classified as ER+ (has oestrogen receptors), PR+ (has progesterone receptors), HR+ (has one or both of these receptors) or HR- (has neither of these receptors). Your cancer may also be classified as HER2 positive or negative. HER2 is a protein which promotes the growth of cancer cells and in HER2 positive breast cancer, there are higher than normal levels of HER2.
In 5-10% of cases, breast cancer is hereditary. The cancer is caused by specific gene mutations (changes) in the BRCA1 (BReast CAncer gene one) and BRCA2 (BReast CAncer gene two) genes.1 There are several other genes other than BRCA1 and BRCA2 that also help make up this percentage.
The BRCA1 and BRCA2 genes are responsible for cell repair and growth, as well as healthy function of breast, ovarian and other body tissues.2 Sometimes, these genes develop mutations which can then be passed down through family generations, increasing the chance of breast (and ovarian) cancers.2
For more information about BRCA1 and BRCA2 genes and how to get tested, please click here.
Breast tissue can typically feel lumpy, therefore it can be difficult to know what is normal and what could be a cancerous lump.
However, some common symptoms to look out for are: 5
Breast cancer classification is complex, but it is typically classified into stages from I – IV based on:
Stage I is the earliest stage of breast cancer, ranging up to Stage IV.
Stage IV is the most serious stage, meaning the cancer has spread to other parts of the body.4
Knowing your breasts is one of the most important things you can do to help detect changes.6
There is no one cause of breast cancer, rather it is a combination of genetic, lifestyle and environmental factors that can increase your risk.
Risk factors include:
There is convincing evidence that combined (oestrogen-progesterone) replacement therapy increases the risk of breast cancer.11
Risk increases with the duration of HRT use, and it is higher in those women who start replacement therapy close to their menopause.11
There are several lifestyle factors you can control to help reduce your risk of developing breast cancer, including:
*To calculate your BMI = (weight (kg))/(height(m))2
Breast cancer in men is not that common, and only makes up approximately 1% of all breast cancer cases.
Like women, there are a number of factors that can increase the risk for breast cancer for men, including: 20
For more information, you can look at the Breast Cancer Foundation NZ’s fact sheet – Male Breast Cancer in New Zealand.
