Breast cancer forms when a malignant (cancer-causing) tumour starts to
grow in the cells of breast tissue. Nearly all breast cancers are carcinomas,
which means the cancer begins in the epithelial cells (lining layer) of the
They are mostly adenocarcinomas, a type of cancer arising from glandular tissue such as the breast ducts or lobules (tissue that make milk). In early stages of breast cancer, the term ‘carcinoma in situ’ means that the cancer is confined to the layer of cells where it began and has not spread to deeper tissues or other organs; however, carcinoma in situ can develop into invasive cancer if left untreated.
ABC describes invasive breast cancer that has spread beyond the breast to the nearby lymph nodes, or to other organs of the body, such as the lungs, distant lymph nodes, skin, bones, liver or brain. ABC can refer to Stage III or Stage IV breast cancer.
Stage III refers to localised ABC, meaning that the cancer has either extensively spread to the lymph nodes and/or other tissue in the area of the breast, but not to distant sites in the body, such as nearby organs.
Stage IV refers to metastatic breast cancer which describes cancer that has spread to distant sites of the body such as the liver, lungs, bones, brain and/or other sites.
A woman may be diagnosed with ABC on her first diagnosis without any history of breast cancer. However, having had breast cancer increases a woman’s risk of having ABC. Once a woman is diagnosed with breast cancer, there is a chance of the cancer progressing and spreading to other parts of the body. Older women also have the higher risk of developing ABC.
In developed countries, 13-21% per cent of women have ABC (Stage III/IV) from their initial diagnosis. However, 20 to 30 per cent of people initially diagnosed with early stage disease will progress to develop Stage 4 or metastatic breast cancer (MBC).
In Malaysia, because of late diagnosis, currently 42% of initial diagnosis is already advanced breast cancer (StageIII/IV).
Each patient’s prognosis – their anticipated success rate for treatment and survival – is different. A common prognosis is five-years, which refers to the percentage of patients who live at least five years after diagnosis.This rate is based upon patients who were treated five years ago, and improvements in treatment now may result in a more positive outlook for patients. However, a patient’s prognosis is dependent on many different factors, and while five-year survival rates may be used as reference, they are not meant to predict an outcome for any specific case.
Although the chance for successful treatment is relatively lower when compared to early stages of breast cancer, the overall outlook in terms of survival and quality of life for women with ABC is improving as cancer therapies become more efficient .