Types of Breast Cancer

Breast cancer is one of the most common cancers for women in the United States, second only to skin cancer. In fact, about a quarter of a million women are diagnosed with some form of breast cancer in the U.S. every year, and that number is growing.

Because of the high incidence rate of this kind of cancer, it is extremely important for women to understand their personal and family medical history and the risk factors they may carry. These include

  • A personal history of breast cancer
  • A personal history of noncancerous breast disease
  • A family history of breast cancer in a mother, daughter, or sister
  • High estrogen exposure (menstruating at a young age, not having children, late menopause)
  • Taking hormones, for example, to control symptoms of menopause or as a birth control method
  • Radiation therapy exposure to the breast or chest area
  • Inherited mutation of the BRCA1 or BRCA2 genes, which can be tested
  • Drinking alcohol
  • Obesity

Although risk factors exist, even without these attributes, women have a significant chance of developing breast cancer at some point in their life.

Signs of Breast Cancer

As with all cancers, the best way to keep damage from breast cancer to a minimum is to catch it as early as possible. The most important thing to look out for is any change in the sensations, look, or feel of the breast and/or nipple of one or both breasts. This might present itself as

  • Swelling, redness, or warmth in a particular area of the breast
  • Change in the shape and/or size of the breast
  • Presence of a lump or hard knot on the breast or under the armpit
  • Persistent pain in one area of the breast
  • Nipple discharge that is clear or bloody (not milky), comes from only one breast or occurs on its own (this could also be a sign of non-cancerous infection)

Just because one or more of these symptoms begins to occur, it does not mean that a woman has breast cancer. However, it is always best to consult with a health professional if you suspect there might be a health condition of any kind. On the flip side, breast cancer may be developing even if none of these symptoms are presenting themselves. Because of this, it is best to get regular screenings by your gynecologist and/or your primary physician.

Diagnosing Breast Cancer

Doctors have many tools that they use to diagnose different kinds of breast cancer and gather information about the particular type of cancer present within a patient. The medical community generally advises that women perform breast self-exams to check their breast tissue for abnormalities or lumps monthly. These exams can and should be supplemented with the additional professional medical care.

Mammograms

Regular mammography screenings are essential for women's health. These medical devices use x-rays to create images of the breast tissue. A radiologist then examines the images to screen for lumps and detect cancer, hopefully in its early stages. Women with a normal degree of risk for breast cancer should begin to get mammograms every 1-2 years beginning at age 40. Doctors recommend that women with an elevated degree of risk get them even more frequently.

Further Tests

If a lump or growth in the breast is found through analysis of a mammogram or hands-on exam, multiple tests and imaging techniques will be used to determine the particular characteristics of a patient's cancer such as

  • Ultrasound Exam, which uses sound waves to create an image of the breast tissue
  • Magnetic Resonance Imaging (MRI), which uses magnet and radio waves to create high resonance, detailed, computerized images of a patient's body
  • Blood Chemistry Studies, which screen for heightened levels of chemical compounds in the body which may indicate various kinds of cancer
  • Biopsy, in which a section of cells is extracted from the lump so that they can be evaluated under a microscope by a pathologist

General Classifications

There are over a dozen different kinds of breast cancer and even more breast diseases involving rapidly dividing cells. Some lumps that develop in the breast are completely benign, while others pose serious and life-threatening risks. This is why any change in the tissue of the breast should be examined by a physician as quickly as possible. There are three types of breast cancer which occur most frequently.

Ductal Carcinoma in Situ

Ductal carcinoma in situ or DCIS is the most common form of noninvasive breast cancer. Noninvasive means that the lump or “carcinoma” has been caught early enough that it has not spread from the milk duct, where it originates, into the surrounding breast tissue. A DCIS is not life-threatening, however, it has the ability to spread and should be addressed immediately which is why it is sometimes referred to as “pre-invasive” or “pre-cancerous.” In addition, having DCIS increases the risk that a patient will develop invasive breast cancer later in their life. The chances of recurrence are between 25 and 30%, but that chance can be reduced to 15% with radiation treatment.

Invasive (infiltrating) Ductal Carcinoma

Invasive or infiltrating ductal carcinoma (IDC) is the most common form of breast cancer, with about 80% of breast cancer incidences falling into this category. This cancer, like the DCIS, begins in the milk duct, but has spread through or invaded the surrounding breast tissue. If left untreated, IDC can continue to infiltrating the body, spreading to the lymph nodes and then to other areas of the body, posing fatal risks.

Invasive (infiltrating) Lobular Carcinoma

Invasive or infiltrating lobular carcinoma (ILC) is the second most common form of breast cancer. Around 10% of cases of breast cancer are ILC. Instead of developing in the milk ducts, which conduct milk from its production center to the nipple, ILC develops in the lobes of the breast, the components that actually produce the milk. This cancer, like IDC, has invaded other tissues of the breast and may spread to lymph nodes then on to other areas of the body.

Although these are the three most common places for breast cancer to occur, many other rare forms of breast cancer exist. Cancer can form in the nipple, the connective tissues of the breast between ducts and lobes, the skin of the breast, or even floating in a mucus-like substance found in the milk ducts. Other rare patterns of cancerous growth in the breast include leaf structures or tubes.

Tumor Characteristics

In addition to distinguishing a case of breast cancer by where it is situated in the body and what it looks like, doctors test tumor biopsies for three different characteristics of individual tumors to determine the best course of treatment. This information can also help physicians predict whether or not the cancer will recur after the particular incident has been treated, how fast the tumor itself might grow, and whether or not the tumor is likely to metastasize or spread throughout the body. A pathologist will likely perform all of the following tests along with many others, although your doctor might focus on the tests that are most applicable in a patient's particular position.

Hormone Receptor Status

Cancer grows through different mechanisms, and some tumors are fueled by the hormones estrogen and progesterone. These tumors will have receptors in the cancerous tissue which are designed to respond to hormones and grow when the hormones come into contact with the receptors.

About 70% of breast cancer cases involved hormone receptor positive tumors while the rest are hormone receptor negative, meaning that there are very few or no hormone receptors present within the cancerous tissue. This test is extremely important because the hormone receptor status determines what kind of chemotherapy drug will be used to treat the cancer.

Hormone receptor positive cancers can be treated with hormone therapy drugs which either bind with the hormone receptors in the tumor, blocking them permanently, or reduce the body's production of hormones in the first place, starving the tumor. Hormone therapies do not work on breast cancers that are hormone receptor negative.

HER2 Status

HER2 is short for the human epidermal growth factor type 2, a type of protein found on the surface of some breast cancer cells. About 10-15% of breast cancers are HER2 positive, meaning that they contain this protein. This is important to the patient because HER2 positive breast cancers can grow more quickly and are more likely to spread to other parts of the body. There are particular chemotherapy drugs that target HER2 receptors, such as Trastuzumab, which is only used on HER2 positive breast cancers.

Proliferation Rate

Multiple tactics can be used and are currently being developed to try and get a clearer picture of how quickly certain breast cancers might grow and spread. These tests are not perfect and are therefore sometimes avoided by physicians who believe that they give inaccurate information. However, as medicine progresses, they will almost certainly become essential tools in determining the prognosis and treatment for breast cancer patients.

The Ki-67 test measures the number of cells in a tumor containing antigens, a protein which is produced during cell division. The more cells with these antigens present generally means a more quickly growing type of cancer. It can give doctors information about what percentage of cells are currently in the process of dividing.

Multigene tests can also help predict whether the cancer will spread or recur after treatment. These tests evaluate the activity of multiple genes simultaneously to try and extrapolate future growth and development of the cancerous tissue.

Stages of Breast Cancer

Along with cancer types and characteristics, there are also different stages of cancer (Stage 0 through Stage IV) which are used to describe the location of the breast cancer, whether or not it has spread to different locations in the body such as the lymph nodes, and the current size of the cancer.

Stage 0

In this stage, the cancer is non-invasive. The cancer has not yet spread to different tissues within the breast or other parts of the body. Ductal carcinoma in situ is a good example of this kind of breast cancer.

Stage I

In stage I, the breast cancer is in the first stages of spreading, called a microscopic invasion. The tumor is either at least 2 centimeters in length but has not spread outside the breast or very small tumors have been found in the lymph nodes (no bigger than 2 millimeters). In some cases, there may be tumors under 2 centimeters in the breast combined with tumors less than 2 millimeters long that, together, are still considered stage I breast cancer.

Stage II

There are very specific specifications for the determination of the standards for stage II breast cancer, although all are considered invasive. Patients may have tumors in the breast between 2 and 5 centimeters, tumors which have spread significantly to multiple lymph nodes, or a combination of these two phenomena.

Stage III

Many combinations of sizes tumors and locations of breast cancer can be considered stage III. This breast cancer has already invaded multiple areas of the body, often including 4-9 lymph nodes and tumors larger than 5 centimeters. Inflammatory breast cancer is also considered a stage III breast cancer. The tumor may have begun to extend into the chest wall or the skin of the breast.

Stage IV

This kind of breast cancer is the most invasive. At this point, the cancer may have spread not only to the lymph nodes, but also to other organs such as the lungs, brain, liver, skin, or bones, among others. This stage is often referred to “metastatic” or “advanced” breast cancer.

Importance of Classifications

Different types and characteristics and stages of breast cancer will necessitate different treatments. While each cancer will require a unique combination of surgery, radiation, and/or chemotherapy, general trends exist to determine what kinds of treatments apply to which classes of breast cancer. Taxotere is recommended as a primary option for some variations and used off-label or as a second or third option in other variations. Understanding your particular variety of breast cancer may help you determine whether or not Taxotere was the best option for your case.

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