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Select a Section to jump to The Normal Breast What is Breast Cancer What are the different Types of Breast Cancer Am I at Risk of Getting Breast Cancer Cancer History Risk Factors Hormonal Risk Factors Lifestyle Risk Factors Other Risk Factors What Does 'Increased Risk' Mean to Me How Can I Reduce the Risk Breast Screening Breast Examination by a Doctor What Happens if I Have an Abnormal Mammogram What Happens if I Have an Abnormal Mammogram Breast Lumps What Happens at the Breast Clinic Fine-needle Biopsy Ultrasound Scan Mammogram Core Biopsy Emotional Reaction to a Diagnosis of Breast Cancer What are the Treatment Options for Breast Cancer Staging Investigations Surgery - What are the Surgical Options When is it Advisable to Have a Mastectomy Rather than a Lumpectomy Possible Problems Following Breast Surgery Radiotherapy - What is it and How it is Used Chemotherapy - What is it and How it is Used Hormone Therapy - What is it and How is it Used Breast Reconstruction Breast Implants Flap Reconstruction Nipple Reconstruction Treatment of Non-invasive Breast Cancer What Happens if DCIS is Left Untreated What are the Treatment Options for DCIS Special Cases of Breast Cancer Breast Cancer During Pregnancy Inflammatory Breast Cancer The Follow-up Clinic What Happens in the Follow-up Clinic Familial Breast Cancer Family History Clinic Genetic Testing

The Normal Breast.

The female breast is made up of fat and milk glands. These glands are composed of basic units called lobules, and are drained by tubes (or ducts) that open at the nipple. The glandular part of the breast is in the middle and feels firmer than the surrounding fatty tissue (Figure 1).

The relative proportions of milk glands, ducts and fat in the breast change with a woman's age and also during pregnancy. For example, the breast of a 25-year-old woman is mainly made up of milk glands, whereas, during pregnancy and breast-feeding, the number of milk glands increases substantially. The female sex hormone oestrogen acts on the breast to maintain the milk glands and ducts. During the menopause there is a decrease in the level

of this hormone that causes the shrinkage of the glandular part of the breast. The glands are replaced by fat, which is why the breasts often feel softer after the menopause. Hormone replacement therapy helps to prevent these changes (see HRT).
The breast also contains special channels called lymphatic vessels. These vessels

transport fluid that accumulates between the cells and return it back into the blood circulation. The lymphatic vessels connect with lymph glands (also called lymph nodes). These are located all over the body. Most of the lymph glands draining the breast are found in the armpit. Cancer cells can spread along lymph vessels and into the lymph glands, causing them to enlarge.

What is Breast Cancer?

The cell is the basic building block of the body, making up all of our tissues and organs. As cells grow old and wear out, new ones replace them. This process is called cell division, as is illustrated in Figure 2.

The balance between dying and growing cells is vital to maintain the normal functioning of our bodies. If the number of growing cells exceeds the number of dying cells, then a lump

(or tumour) will develop. If the cells in the tumour divide haphazardly and grow in an aggressive manner, this is called a cancer or malignant tumour.
Malignant cells have the potential of invading adjacent tissues and can spread to other parts of the body some distance away from the main (or primary) tumour. This process of distant spread is called metastasis. It can occur through the blood stream or the lymph vessels.
A breast cancer occurs when the cells of the milk glands or the milk ducts grow and divide

in a disorderly manner. This may be detected as a lump in the breast. It can take months or years for a tumour of 1 cm in diameter to grow in the breast. It is estimated that a tumour of this size contains one billion breast cancer cells!

What are the different Types of Breast Cancer?

There are two main types of breast cancer: invasive and non-invasive (Table 1).
 

Type 1 - Invasive Breast Cancer

This cancer is more aggressive and has the ability to spread elsewhere in the body and thus cause death.
 

Type 2 - Non-invasive Breast Cancer
 

This type is confined to the ducts or lobules of the milk glands. It is a non-invasive cancer and does not usually spread to other parts of the body. However, it may develop into an invasive type if left untreated. The medical name for non-invasive breast cancer is ductal carcinoma in situ (DCIS) if it occurs in the milk gland ducts (tubes), or lobular carcinoma in situ (LCIS) if it occurs in the gland lobules.

LCIS is not considered as cancer as such. The presence of this abnormality in a breast biopsy means the patient has an increased risk of developing breast cancer. The risk means that about 1 in 3 women with LCIS will develop breast cancer within 30 years of being diagnosed with the original condition.
 

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