Before discussing the types of breast cancer, it is very important to know about the normal breast. The female breast which contains mainly:
- Lobules (Milk-Producing glands)
- Ducts (Small tubes that carry milk from lobules to nipples of the breast)
- Stroma ( fatty and connective tissues surrounding the ducts and lobules)
- Lymphatic vessels
- Blood vessels
A Question is Arises: How can Breast Cancer Begin in the Human Body?
- Most of the cases of cancer patients affected by Ductal Carcinoma, that has the starting point of the line of lobules and other tissues.
- Another way to effect bloody from cancer is the Lymphatic System. It is important to understand the lymphatic system. This system has several parts.
Lymph Nodes: Small in Shape
Collection of Immune System Cell: Important in Fighting actions
Lymphatic Vessels: These vessels carry Lymph; a clear fluid, instead of blood
Lymph: A tissue fluid and waste products
Breast Cancer cells can enter lymphatic vessels and begin to grow in lymph nodes. Most lymphatic vessels in the breast connect to lymph nodes under the arm known as Axillary Lymph nodes. Inside the chest, some lymphatic vessels connect to the lymph nodes known as Internal Mammary Lymph Nodes. Nodes are above and below the Collarbone known as Supraclavicular/ Infraclavicular Lymph Nodes.
It is important to know that, whether cancer cells have spread to lymph nodes or not. If cancer cells spread to lump nodes, its a higher chance to spread cancer to other organs. The extent of metastasis is important and helps doctors to make a treatment plan to cure cancer. The spreading of cancerous cells to other organs of the body known as Metastasis.
General Terms to Understand Breast Cancer Types
It is very important to understand some terms of cancer, that will assist in a clear understanding of breast cancer. Some basic terms are listing below:
- Carcinoma: Carcinoma is a term of cancer that begins in the lining known as Epithelial cells, of the organs. Most of the breast cancer types are carcinomas.
- Adenocarcinoma: A type of carcinoma that beings in Glandular Tissues. Glandular tissues are a specific type of tissue, that makes and secretes a substance. The Ducts and Lobules of the breast are glandular tissues. These tissues make milk in the breast. Cancer that begins from these tissues called Adenocarcinomas.
- Carcinoma in Situ: This term is used, when cancer is in the early stage. It means, Cancer cells confined to the place, where it is started. In this, Cancer cells not invade deeper in the tissues of spread in other organs. This is also known as Non-invasive or Preinvasive Breast Cancer.
- Invasive/Infiltrating Carcinoma: Opposite term from “Carcinoma in Situ”. In this condition, cancer cells have spread in other tissues and layers where it is started. Most cases of Breast cancer are Invasive in nature.
- Sarcoma: This term is used when cancer starts from the connective tissues like muscles, fat tissues, or blood vessels. This is the rarest type of cancer.
Types of Breast Cancer
There are many types of breast cancers. We will categorize two types of breast cancers. In one section, we are going to discuss the most common types of breast cancer. While, in other section, we discuss the rare types of breast cancer with the complete explanation. It should be noted that, in some cases, a single breast can have a different combination of cancer cells. The combination of the cancerous cells in the breast can be both Invasive and Preinvasive.
Most Common Types of Breast Cancer
In this section, we are going to discuss the types of cancer that are commonly found in the patients.
Ductal Carcinoma in Situ
The most common type of Preinvasive Breast Cancer is Ductal Carcinoma in Situ (DCIS). DCIS means the cancerous cells, that remain inside the ducts. Cancer cells do not spread in the surrounding breast tissue through the wall of ducts. About 20% of the breast cancer cases effected by DCIS. A Mamogram is the best way to diagnose DCIS. Normally, women diagnosed early DCIS, can be cured and survived.
Lobular Carcinoma in Situ
Lobular Carcinoma in Situ (LCIS), also known as Lobular Neoplasia. Actually, it is true cancer but it is simply classified as a Preinvasive type of Breast Cancer. The start point of this cancer is Glandular tissue, known as Milk producing glands. The reason for invasive is, it does not grow with the walls of lobules. There is a risk in women of spreading LCIS from one breast to another. For this reason, Women should be regularly to visit doctors and should do mammography tests.
Invasive Ductal Carcinoma
Invasive of Infiltrating ductal Carcinoma (IDC) is the most common type of Invasive breast cancer. Almost 80% of invasive breast cancer cases are IDC. IDC starts from a milk passage of breast. It breaks through the wall of the duct ad grows into the fatty tissues of the breast. when it breaks through the wall of the duct, It a higher probability to spread in other parts of the body through the bloodstream and lymphatic system.
Invasive Lobular Carcinoma
Invasive lobular carcinoma (ILC) starts in the milk-producing glands (Lobules). It can also spread to other parts of the body. About 20% of cases of an invasive type of cancer affected by ILC. ILC hard to detect in mammography tests.
Rare Types of Breast Cancers
Some rare but fetal types of Breast Cancers are listed below with complete details:
Inflammatory Breast Cancer
One of the rare types of breast cancer is Inflammatory Breast Cancer (IBC). Almost 1-3% of all breast cancers contain IBC Cancer. Usually, there is no single lump or tumor. Due to IBC, skin of the breast look red, feel warm, thick skin, pitted appearance that resembles an orange peel. Doctors and researchers now know that these changes are not due to the inflammation in infection. All of these changes due to the cancer cells blocking lymphatic vessels in the skin.
Breast affected by this IBC may become larger, firmer, tender, or itchy. In the early stages of IBC, inflammatory breast cancer is often mistaken for an infection in the breast known as mastitis. Often, IBC is first treated as an infection by prescribing antibiotics. In the case of symptoms look like cancer, they will not improve and the skin should be biopsied to look of cancer.
IBC effected breasts have no actual lump and it cannot be diagnosed by mammography. Due to this reason, it is more difficult to diagnose it in the early stages. IBC has a higher chance of spreading and worst prognosis than invasive ductal or lobular cancer.
Triple-Negative Breast Cancer
Triple-Negative Breast cancer is one of the most fatal cancers, mostly diagnosed in young women. This cancer term is used to describe usually Invasive Ductal Breast Carcinomas. These cells lack estrogen receptors and progesterone receptors. These cells also lack HER2 proteins on their surfaces. This protein is made by a specific gene named the HER2/neu gene.
TNBC tends to spread more rapidly than other types of cancer. Reason for lacking estrogen and progesterone receptors in tumor cells. No hormone therapy and drugs can target HER2, that can effective against this cancer.
Mixed tumors contain a variety of cell types, such as invasive ductal carcinoma combined with invasive lobular carcinoma. In this situation, the tumor is treated as if it were an invasive ductal carcinoma.
This special type of infiltrating breast cancer has a rather well- defined the boundary between tumor tissue and normal tissue. It also has some other special features, including large cancer cells and the presence of immune system cells at the edges of the tumor. Medullary carcinoma accounts for about 3% to 5% of all breast cancers. The prognosis for this kind of breast cancer is generally better than that of the more common types of invasive breast cancer.
Metaplastic carcinoma (also known as carcinoma with metaplasia) is a very rare type of invasive ductal carcinoma. These tumors include cells that normally are not found in the breast, such as cells that look like skin cells (squamous cells) or cells that make bone. These tumors are treated like invasive ductal carcinoma.
Mucinous Carcinoma is a real type of IDC. An abnormal cell is known as Mucin, a component of Mucus that is responsible for this cancer. Although many other types of Breast cancer also produce mucus. Mucus forms a part of the tumor in Mucinous carcinoma. The prognosis from this disease is usually better than other invasive breast cancers.
Paget Disease of the Nipple
This type of breast cancer starts in the breast ducts and spreads to the skin of the nipple and then to the areola, the dark circle around the nipple. It is rare, accounting for only about 1% of all breast cancers. The skin of the nipple and areola often appears crusted, scaly, and red, with areas of bleeding or oozing. The woman may notice burning or itching.
Paget disease is almost always associated with either ductal carcinoma in situ (DCIS) or, more often, with invasive ductal carcinoma. Treatment often requires a mastectomy. Hence, If only DCIS is found (with no invasive cancer) when the breast is removed, the prognosis is excellent.
Tubular carcinoma is another unique type of invasive ductal carcinoma. This type of carcinoma is called “tubular” because of the way the cells appear when seen under the microscope. Tubular carcinomas account for about 2% of all breast cancers and tend to have a better prognosis than most invasive ductal or lobular carcinomas.