Breast cancer is referred to as malignant breast neoplasm in medical circles. It is a cancer that develops in the cells of the breast tissue. It is classified into various types.
The aim of classifying breast cancer is to select the most appropriate treatment option. Aggressive and life-threatening types are treated with aggressive treatment options and the adverse side effects are tackled. Less aggressive cases can be treated with less aggressive treatments
It can occur in women as well as in men though, in women, it is 100 times more common than in men.
It is the second most common cancer diagnosed in women in the United States, with skin cancer being the most common. However, worldwide, it tops the list along with lung cancer.
It is also the second leading cause of death after lung cancer (among women with cancer).
- One in 8 women will develop breast cancer during their lifetimes.
- Two-thirds of these women are 55 or older.
- One-third are between 35 and 54
Its survival figures are rising and death rates are steadily falling primarily due to better awareness, early detection, and more advanced treatment options.
The tissue cells of the breast mutate and turn into cancer cells. There are causes and risk factors that trigger this cellular mutation. The cells then start growing and multiplying at an uncontrollable rate. They form a tumor that can be felt by hand and detected by a mammogram, ultrasound, and MRI of the breast.
The tumor can grow in size and spread to nearby lymph nodes or through the bloodstream to other parts of the body such as the organs. It can also grow and spread to the skin or chest wall around the breast. It is then called metastatic breast cancer.
Depending on the type, it can take years to spread outside the breast or it can grow and spread quickly.
However, most breast lumps are benign and not malignant. The nonmalignant tumors also grow but not like the cancerous growths. Their growth is gradual and they do not extend outside the breast.
They do not kill you but they can increase a woman’s risk of developing breast cancer.
Where does breast cancer originate?
Ductal cancers, are the most common and account for 80% of breast cancers. They originate in the milk ducts that lead to the nipple.
Lobular cancers start to develop in the glands that make milk.
Breast sarcomas are rare and start to develop in the connective tissue that supports the ducts and lobules of the breast.
Breast lymphoma is also rare, originates in the breast lymphoid tissue, and includes primary breast lymphoma (PBL) and secondary breast lymphoma (SBL).
At times, the cancer may not form a lump in the breast. Such cancers can be detected by mammograms, which can detect them at a very early stage even before any symptoms appear.
Breast cancer in men
Men can get cancer of the beast too, but it is rare accounting for less than 1% of all cases. About 1 out of every 100 cases diagnosed in the United States is found in a man.
Breast cancer in men is usually a ductal carcinoma and tends to have a poor prognosis due to late diagnosis. It can occur at any age but is most common in old age. The cause of this disease in men is not known.
Every human has a certain amount of breast tissue. In men, the breast tissue does not get developed.
The most common types of breast cancer in men are the same kinds in women:
- Invasive ductal carcinoma. The cancer cells begin to develop in the ducts and then grow beyond the ducts into neighboring parts of the breast tissue. Invasive ductal carcinoma can also undergo metastasis and spread to other parts of the body.
- Invasive lobular carcinoma. This type begins in the lobules and then spreads from the lobules to the neighboring breast tissues. It can also spread to other parts of the body.
- Ductal carcinoma in situ (DCIS). DCIS can lead to invasive breast cancer. In this type, the cancer cells are present only in the lining of the ducts and have not spread to other tissues in the breast.
Types of breast cancer
Breast cancer is of various types. It is classified based on where in the breast it has originated, whether it has spread, and whether it depends on hormones to grow. The choice of treatment depends on the type of cancer that has developed.
It is often classified along the following lines:
- Non-invasive breast cancer or lobular carcinoma in situ
- Invasive lobular carcinoma
- Ductal carcinoma in situ
- Invasive ductal carcinoma
- Inflammatory breast cancer does not start as a lump but begins with swelling and redness of the breast.
- Paget’s disease of the nipple is a rare type in which malignant cells develop in and around the nipple.
Non-invasive breast cancer (Cancer in situ)
Non-Invasive Breast cancer stays within the tissue in which it has originated. For example, cancer that has originated in the lobules of the breast stays within the lobules and does not grow into the neighboring normal breast tissue beyond the lobules.
Similarly, cancer that has originated within the ducts stays within the duct and does not invade the neighboring normal tissue. This type of cancer is called carcinoma in situ.
Ductal carcinoma in situ (DCIS) is the most common type of non-invasive cancer of the breast. It originates in the milk ducts of the breast and does not spread into the surrounding breast tissue. This type does not kill you, but it can increase the risk of developing invasive cancer of the breast.
Lobular carcinoma in situ (LCIS) is a non-invasive type of cancer that starts and grows in the milk-producing glands called lobules. It does not invade the surrounding breast tissue. LCIS also does not kill you it can also increase the risk of developing invasive breast cancer.
Invasive breast cancer
Invasive breast cancer is cancer, which spreads into the neighboring breast tissue beyond the lobules or the milk ducts from which it has originated. This type is more common.
Invasive ductal carcinoma (IDC) is the most common type accounting for about 80% of all breast malignancies. In this type, cancer that originates in the milk ducts of the breast grows and spreads into the surrounding breast tissue. Later, IDC can spread to the nearby draining lymph nodes and to other parts of the body.
Invasive lobular carcinoma (ILC) is the second most common type of breast cancer, coming second to invasive ductal carcinoma. In invasive lobular carcinoma, cancer that originated in the milk-producing lobules of the breast spreads into surrounding breast tissue. In due course, ILC can spread to the neighboring lymph nodes and other parts of the body. Invasive lobular carcinoma accounts for about 5% to 15% of all breast malignancies.
Mixed breast tumor
A mixed tumor is a tumor that contains malignant lobular cells as well as malignant ductal cells. It is also referred to as “invasive mammary breast cancer” or “infiltrating mammary carcinoma.” It is treated as ductal carcinoma.
These mixed ductal/lobular carcinomas have distinct clinicopathologic features of both lobular and ductal carcinomas.
At times, there is more than one tumor in the breast. It can either be multifocal or multicentric.
Multifocal breast cancer
This is a type of invasive cancer in which multiple tumors arise in the same quadrant of the breast. In this type, at least two invasive tumors develop in the same quadrant, or area, of the breast.
The multifocal type is divided into five stages, beginning from zero. These various stages indicate if, and how far, a tumor has spread.
Multicentric breast cancer
In this type of breast tumor, the different tumors originate separately and are often found in different areas of the breast separated by tissue.
Inflammatory breast cancer
Inflammatory breast cancer is rare and aggressive and accounts for about 1 to 5 percent of all diagnosed cases in the United States. The cancer cells block the lymph vessels that are present in the skin of the breast.
This type is called “inflammatory” because the breast becomes swollen and inflamed.
They are mostly invasive ductal carcinomas because they originate from the cells that line the milk ducts. Being invasive, they later spread beyond the ducts.
This inflammatory type grows and spreads rapidly, often over weeks or months. It is often diagnosed when it has already spread and is either in stage III or IV.
Paget’s disease of the breast
Paget’s disease of the breast is a rare type. It starts to grow on the nipple and spreads to the areola (the dark circle of skin) around the nipple.
Paget’s disease of the breast is found to develop mostly in women after the age of 50 years. Most of these women also have underlying ductal breast cancer, which may be invasive or noninvasive.
Triple-negative breast cancer
Triple-negative breast cancer (TNBC) is a rare cancer of the breast, About 10-20% of the cases are triple-negative.
It is a very aggressive type of invasive cancer that is very challenging to treat. In this type, the cancer cells do not have any of the receptor cells that are usually present.
When it tests negative for estrogen receptors, progesterone receptors, and HER2/neu receptors, it is referred to as triple-negative breast cancer.
After skin cancer, breast cancer is the most common malignancy among women in the United States. Its statistics, worldwide and for the United States are alarming.
However, its awareness has increased and so has research funding. Survival rates have improved due to the implementation of screening guidelines, early diagnosis and confirmation, more in-depth studies, and newer treatments.