Breast cancer is a cancer, which develops in breast tissues. It affects ducts carrying milk and glands making milk. Gland making milk is known as lobules. It may occur in both men and women but it is more common in women and is rare in men. Breast cancer can affect different tissues of the breast. It can affect ducts or tube moving milk from the breast to the nipple or milk producing parts lobules. It may be invasive or spreading from the milk duct or lobule to other tissues in the breast. It may also be non-invasive or confined to a smaller part of breast or in situ. Breast cancer in situ may affect the lining of the milk ducts or lobules and not invade nearby tissues. It may progress to invasive cancer.

Many patients may suffer from estrogen sensitive breast cancer. These types of breast cancer have receptors for estrogen on the surface of their cells. They are also known as estrogen receptor-positive cancer or ER-positive cancer. Some breast cancers may HER2-positive. HER2 is a gene helping cells growth, division or repair. This type of breast cancer quickly spreads and is more likely to be recurring.

Types of Breast Cancer

Breast cancers are primarily of two types Invasive Breast Carcinoma (IBC) or non-invasive (Carcinoma In Situ).

Invasive Breast Carcinoma (IBC) is further classified as :-

  • Invasive Lobular Carcinoma (ILC)  – Invasive lobular carcinoma affects the lobules, the gland, which produces milk. It could spread to other parts of body as well. It is capable of entering the bloodstream or the lymphatic system and could travel with it. It could lead to thickening of the breast. It is more common in women above 45 years of age.
  • Invasive Ductal Carcinoma (IDC) – It is the most common invasive breast cancer. It develops in milk ducts and spread to nearby tissues. It may also affect other parts of the body like bone, brain, liver, and lungs through blood or lymphatic system. In this type of breast cancer, lump growth is hard and irregularly shaped. Women, who are more than 40 years of age, are more likely to develop this disease.

Non-Invasive or Carcinoma In Situ is further classified into two types, which are discussed below.

  • Lobular Carcinoma In Situ (LCIS) – It affects only lobules or glands that produce milk. Tumors in this type of cancer consist of small uniform cells. These cells are similar to cells of breast lobules. It is more common in women nearing menopause or between 40 and 50 years of age. It may not show up in mammogram and may not form lump. These tumors are usually HER2 negative (-) and belong to estrogen receptor-positive cancer or ER-positive cancer. It is highly treatable and is treated with hormone therapy.
  • Ductal Carcinoma In Situ (DCIS) – Ductal carcinoma in situ is confined to the milk ducts of the breast. Tumors are made of irregular cells. They are nearly similar to cells of breast ductal system. It can be detected through mammograms as they form lumps. Most cases of this type of cancer not spread to other parts of body but some may change to invasive breast cancer (IBC). It is treated with surgery with or without radiation. It may be recurring. Thus treatment plan is devised after considering nuclear grade, cell necrosis, and cell and tumor architecture. This type of breast cancer is ER positive.

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