BREAST CANCER

Breast Cancer

Breast Cancer

Literature Review

Breast cancer, too, is not just one disease, but several. It can be found in a precancerous state (which might go on to develop into invasive cancer if it is not treated), as a cancer which has not yet spread, or after it has spread to other organs. It can grow very fast or very slowly or somewhere in between (Bernstein et al., 1999). Breast lumps are common in women of all ages, but in younger women, particularly, they are usually non-malignant. Though it is rare, men can and do also get breast cancer. Breasts are composed mainly of fat and breast tissue, together with nerves, veins, arteries and the connective tissue that helps to keep it all in place. The main chest muscle is behind the breast and in front of the ribs in the chest wall. The breast (see Figure 1) is divided into around 20 lobes which look something like bunches of grapes. The 'grapes' are called lobules and the 'stems' are called ducts (Brown & Leffall, 2003). The lobules produce milk and the ducts, which are thin tubes, transport the milk from the lobules to the nipple openings during breastfeeding.

Figure 1

Strands of fibrous tissue and globules of fat develop around the lobules and ducts in the breast during puberty. The breast also contains vessels carrying blood and lymph. Lymph is a yellow fluid that bathes cells. It is derived from blood as it passes through the blood vessels within a tissue, and is returned to the blood after passing through lymph glands. It flows through the lymphatic system throughout the body to help fight disease. The lymph vessels lead to lymph nodes, small bean-shaped organs which can trap bacteria or cancer cells travelling through the body in the lymph. There are clusters of lymph nodes near the breast in the axilla (under the arm), above the collarbone and in the chest (Cuzick, 2003). Benign or malignant tumours can develop in any of the breast's tissues-skin, gland, duct, fat, nerves, muscles, blood vessels or fibrous tissue.

Male breast tissue normally remains undeveloped, with rudimentary ducts ending in tiny lobular buds, like that of females before puberty (Iredale, 2003). After the menopause, when the ovaries stop producing hormones, the number of lobules decreases, and those that are left shrink. This means that the breasts, which are then composed of a higher proportion of soft fat, are less dense. And this means that interpretation of the X-rays is more reliable, so mammography is more likely to be effective in picking up abnormalities in post-menopausal women than in younger women with denser, firmer breasts.

Different Types of Breast Cancer

There are two main types of breast cancer-non-invasive or 'in situ' (cancers that are confined to the ducts or lobules and have not spread beyond the layer of tissue where they developed) and invasive (cancers that have started to spread into surrounding tissue).

Non-invasive ('in situ')

Ductal carcinoma (cancer) in situ (DCIS) is non-invasive and is becoming more common ...