There are two main categories of breast cancer. These are invasive and non-invasive.
Invasive breast cancer spreads from the breast gland or duct to other parts of the breast or body. Additionally, non-invasive cancers are exclusively centred around the breast gland or the duct. Based on these categories, the various types of breast cancer are:
Non-invasive Breast Cancer Types
There are only 2 types of non-invasive breast cancer. These are:
Ductal Carcinoma in Situ (DCIS)
In this type of breast cancer, cancer is still concentrated in the ducts. However, it may spread to other tissues if left untreated. Cancer has not yet invaded surrounding cells.
Lobular Carcinoma in Situ (LCIS)
In this type of breast cancer, the disease is concentrated or confined to the breasts' milk-producing glands. It may, however, spread to different parts of the breast.
Invasive Breast Cancer Types
There are broadly 8 types of invasive breast cancer. They are:
This extremely rare form of breast cancer occurs when cancer grows in the breasts' blood or lymph cells.
Inflammatory Breast Cancer
It is a rare yet rapidly growing breast cancer. The breast cancer symptoms include redness, swelling and tenderness in the breast. It is still unclear what causes inflammatory breast cancer. However, it is believed that cancer begins in the lymph vessels of the skin.
Invasive Ductal Carcinoma (IDC)
80% of invasive breast cancer cases are of this type. IDC starts in the ducts connecting the milk gland to the nipple. It then breaks through the duct wall, consequently invading healthy fatty tissues of the breast.
Invasive Lobular Carcinoma (ILC)
ILC accounts for around 10% of invasive breast cancer cases. This breast cancer typically starts in the milk glands and then spreads to surrounding tissues or other body parts. It also has many subtypes, which are:
- Adenoid Cystic Carcinoma: This type of cancer accounts for 0.1 to 1% of all breast cancers. The lymph node plays an important role in this type of cancer, and there is distant metastasis. Typically this cancer occurs in the salivary glands.
- Low-Grade Adenosquamous Carcinoma: Metaplastic breast cancer is another extremely rare form of breast cancer. However, there can be lesions that are mistaken for cancer. Hence diagnosis will be performed extremely carefully.
- Medullary Carcinoma: Medulla, in this case, refers to the soft structure of the tumour. Therefore, it is described as a carcinoma with medullary features rather than strictly a medullary carcinoma.
- Mucinous Carcinoma: This type of cancer occurs in the mucus. Mucus is a slimy, slippery secretion in the body found commonly in the stomach and the trachea.
- Papillary Carcinoma: Primarily affecting those women who suffer from menopause, this type of cancer has finger-like projections and tumours.
- Tubular Carcinoma: Tubular cancer gets its name from the tube shape of the cancer cell. It is a slow-growing type of cancer.
Male Breast Cancer
Men also have breast tissue, and hence they can get breast cancer. However, it is much rarer in men than it is in women. However, the breast cancer symptoms are the same as those of women.
Metastatic Breast Cancer
Metastatic breast cancer is another name for stage 4 cancer type that has spread to other parts of the body. Therefore, it may reach the bone, liver, or lungs. Since it is an advanced type of cancer, doctors will draw up a speedy treatment plan to combat the breast cancer symptoms.
Paget's Disease of the Nipple
This type of breast cancer grows in the ducts of the nipple. But as the disease persists, it affects the areola, which is the skin surrounding the nipple.
Phyllodes Tumours of the Breast
It is another rare breast cancer type. Growing in the connective tissue of the breast, it may be benign or cancerous.
Triple-Negative Breast Cancer
Triple-negative effects 10-15% of the population with breast cancer. To be diagnosed as a triple-negative, the tumour should have all 3 characteristics:
- Lack of oestrogen receptors that bind to the oestrogen hormone. Oestrogen plays a dominant role in stimulating breast cancer cells to grow.
- There is a lack of progesterone receptors that attach to the cell.
- It shouldn't have HER2 proteins on the surface of the tumour.
It is called triple-negative because oestrogen, progesterone and HER2 proteins should not be present in the tumour. Further, triple-negative breast cancer is hard to treat as it does not respond to hormonal therapy.
In all these cases, the breast cancer symptoms may vary, and the reader is requested to read individually on all these subtypes.