Breast cancer occurs most often in women, although men can also develop this disease. Each year, more women in the United Kingdom are diagnosed with breast cancer than with any other, cancer. 1 in 8 women in the UK will develop the disease at some time in their life. Here, we focus on breast cancer in women and recommend that men who have been diagnosed with breast cancer speak to their doctor for information specific to them.
Breast cancer can develop at any age, but the risk of developing it increases as women get older. The majority of women who develop breast cancer are past the menopause but about 1 in 5 develop the condition below the age of 50. Almost half of female breast cancer cases are diagnosed in the 50-69 age groups. This is why women in this age group and those aged 70 are invited to attend the UK national screening programme where they have routine 3 yearly mammograms. Although very few cases of breast cancer occur in women in their teens or early 20s, it is the commonest single cause of death among women in the UK between the ages of 35-45 years. It is also the most commonly diagnosed cancer in women aged 35-39.
While 5% to 10% of breast cancers are related to an inherited defect in one of two genes (BRCA-1 or BRCA-2), the majority of cases develop for reasons we do not yet understand. As a general rule, those at higher risk of developing breast cancer include women whose close relatives have had the disease, women who have not had children and women who had their first child after the age of 30.
Breast cancer may be divided into three stages, reflecting the extent to which the cancer has spread in the body.
- Early stage breast cancer is usually confined to the ducts (which transport milk to the nipple during lactation (breast feeding)) or to the lobules (small areas of tissue where milk is produced in the breast) and is known as non-invasive cancer. If the cancer is confined to the ducts, it is called ductal carcinoma in situ (DCIS) and if it is confined to the lobules, it is called lobular carcinoma in situ (LCIS). At this early stage, the cancer usually cannot be felt as a lump in the breast. However, DCIS can sometimes cause signs and symptoms such as a breast lump or a bloody discharge from the nipple. Because DICS usually has no symptoms however it is normally detected incidentally by mammography.
- Invasive stage breast cancer is characterized by a spread of the cancer beyond the ducts or lobules and into the surrounding areas of breast tissue. At this stage, the cancer may be detected through breast self-examination, by a clinical breast examination performed by health care professional, or by mammography.
- Metastatic stage breast cancer is cancer that has spread (metastasised) to other areas of the body, including nearby lymph nodes. The most common lymph nodes it spreads to first are in the axilla ( armpit) and this can cause a lump in that area. From there it can spread into the bloodstream to other areas, most commonly the lung, liver and bones. At this stage, treatment requires the combined effort of several specialists, including surgeons, oncologists, and radiologists.