This year, nearly 253,000 U.S. women will be diagnosed with invasive breast cancer. Many will successfully beat the disease. For more than 40,000 families[4] however, finding a way to live without their daughter, sister, mother or friend will become their reality.

According to the American Cancer Society, breast cancer is the second leading cancer in women, next only to skin cancer.[8]

What Is Breast Cancer?

Breast cancer takes root as cancer cells begin to grow, usually forming a tumor in or around breast tissue. Sometimes a mammogram detects cancer in the breast, but often a physician (or the patient themselves) identifies a mass during manual examination. If the tumor is capable of growing and spreading (metastasizing) and can invade surrounding tissue, it is considered malignant.

Types of Breast Cancer

Several types of breast cancer exist, however the three most common include ductal carcinoma in situ, invasive ductal carcinoma, and invasive lobular carcinoma. The cells of the breast are affected differently depending on the specific type of breast cancer present. The female breast consists of a network of lobules (milk glands), ducts, fat, connective tissue, blood vessels and lymph nodes. Each part of the breast is vulnerable to cancerous cells.

The majority of breast cancers are classified as “carcinomas” or tumors that begin in the cells that line tissue and organs. Breast adenocarcinomas begin in either milk ducts, or the milk production glands called, lobules.[9]

Less Common Breast Cancers

Other less common breast cancers include sarcomas, phyllodes, Paget disease, and angiosarcomas. These originate in muscle, fat, or connective tissue cells of the breast.

*Breast tumors may consist of more than one type of breast cancer. Rarely, (but possible) are cancers made up of cells that do not form lumps in tissue at all.
Breast cancer can be described as either, “in situ”, which literally means, “in place” or “invasive/infiltrating”, meaning the cancer has spread to breast tissue.

In situ Breast Cancers

Ductal carcinoma in situ (DCIS)—This type of breast cancer is considered non-invasive or pre-invasive. Ductal carcinoma begins in the cells that line the ducts that carry milk to the nipple. Abnormal cells have yet to spread outside the duct. DCIS is the most common breast cancer among women with the disease.
Lobular carcinoma in situ (LCIS) consists of abnormal cells that grow in the lobules. These do not grow outside of lobule walls.

Invasive (Infiltrating) Breast Cancer

When breast cancers spread into surrounding breast tissue they are known as invasive breast cancers. There are several different types of invasive breast cancers, but two are most common. These are invasive ductal carcinoma and invasive lobular carcinoma.

In about 1% to 5% of all breast cancers, inflammatory breast cancer is present. It is an invasive breast cancer as well.

Paget disease of the nipple

Paget disease of the nipple begins in the ducts of the breast, and eventually spreads to the nipple skin and areola. It is rare and only present in about 1% to 3% of breast cancer cases.

Phyllodes tumor

A Phyllode tumor develops in the connective tissue of the breast. Most cases are benign, but occasionally can be malignant cancer.

Angiosarcoma

Sarcomas of the breast are very rare comprising only 1% of breast cancers. Angiosarcoma is a type of cancer that originates in the cells that line the blood vessels or lymph vessels. This type of cancer can also involve breast tissue or breast skin. Angiosarcoma has been associated with previous radiation therapy to breasts.[8]

Breast Cancer Symptoms

Symptoms of breast cancer vary and may include:

• Thickening or a lump in the breast tissue that feels different from other tissue around it.
• Any change in the size, shape, or appearance of the breast.
• Dimpling, or changes to breast skin.
• Inverted nipple that was not there before.
• Changes to the areola (skin around the nipple) or other breast skin that include peeling, flaking, or scaling.
• Pitted skin/redness of breast skin.

Causes of Breast Cancer

While researchers are not certain about the exact causes of breast cancer, they do know that cancer cells begin in the breast and divide more rapidly, generally forming a lump or tumor. These cells can metastasize and spread to lymph nodes.[2]

Risk Factors for Breast Cancer

Scientists have identified several risk factors including hormonal, lifestyle, and environmental factors that may increase an individual’s chance of developing breast cancer. Breast cancer appears to be caused by a combination of inherited traits, as well as environment.

Risk factors for breast cancer include:

Inherited genes—Between 5% and 10% of cancers may be linked to inherited gene mutations, BRCA1 and BRCA2. These gene mutations raise the risk for ovarian cancer as well.

Being female—Women are 100 times more likely than men to develop breast cancer.[10]

Age—The risk of developing breast cancer increases with age.

Personal history—Once an individual develops breast cancer in one breast, the risk of developing it in the other breast is much higher.

Family history—If a mother, sister, or daughter has had breast cancer, an individual’s risk for developing the disease is much higher.

Exposure to radiation—Radiation exposure to the chest area as a child or young adult may increase the risk of breast cancer.

Obesity—The risk of breast cancer is increased in individuals who are obese.

Early menstruation—Breast cancer risk is higher in women who menstruated before age 12.

Late menopause—Women who experience menopause later in life are more likely to develop breast cancer.

Later childbirth—Women who give birth to their first child after age 30 are at increased risk for breast cancer.

Never pregnant—For women who have never been pregnant, the risk of breast cancer is higher.

Hormone therapy—The risk of breast cancer is higher for women receiving combined estrogen and progesterone hormone replacement therapy for menopausal symptoms.

Alcohol consumption—Drinking alcohol may increase the risk of breast cancer.

Dense breast tissue—Women who have dense breast tissue are 2 to 6 times more likely to develop breast cancer than those with less dense breast tissue.[1]

Diagnosing Breast Cancer

Breast cancer screening is recommended for women by age 45. From 45 to 54 a yearly mammogram should be done, and after age 55, biennial screening is acceptable.[guidelines] During routine ob/gyn doctor visits, many physicians perform a manual breast exam, feeling for lumps in the breast tissue, checking for nipple discharge, or swelling in the lymph nodes under the armpits.

The most common methods of screening for breast cancer include mammograms, breast MRI’s, and breast ultrasounds. If changes or abnormalities are detected in breasts, a biopsy will be performed to definitively determine if cancer is present.

Breast Cancer Stages

Breast cancer, once diagnosed is further classified into stages. These help identify how large and how extensive a tumor has grown, and whether or not it has spread to other parts of the body. Staging helps medical professionals determine the prognosis for each patient and the best course of treatment. A blood test, mammogram, MRI, Bone Scan, CT scan (computerized tomography), or PET scan (position emission tomography) may be used to aid classification.

Staging of breast cancer is done by a pathologist and is based on tumor tissue and lymph nodes that may be removed in the course of surgery.
TNM System of Staging
The TNM system of staging is the most common method used in identifying the progression of breast cancer.
T = Tumor size
N = Lymph Node status
M = Metastases
Stages of Breast Cancer
Breast cancer stages are also classified through a number system, 0 to IV. Each stage is dependent on the size of the tumor (T), the lymph node status (N), and whether the cancer has metastasized (M).
Stage I cancer for example, is classified as I (T1N0M0). This translates to: stage I, T1 tumor (smaller than 2 cm), no cancer in the lymph nodes, and no metastasis.
Each stage is classified using the TNM system below.

Once cancer is classified and staged, the designation is permanent, regardless of whether a tumor shrinks, spreads, returns after treatment, or enters the lymph nodes. Further identifying information is attached to the original classification if tumors change shape or size, or spread.[6]

Breast Cancer Treatment

Breast cancer is treated in a number of ways depending on the type and stage of the disease. Many times it is resolved or reduced using a combination of treatments.[3]

The following breast cancer treatment protocols are most common.

Breast-conserving surgery (also called a lumpectomy, quadrantectomy, partial mastectomy, or segmental mastectomy) – A surgery in which only part of the breast containing the cancer is removed is known as breast conserving surgery. The goal is to remove the cancer as well as some surrounding normal tissue. The amount of breast tissue removed depends on the size and location of the tumor, and other factors.

Mastectomy—A surgery that consists of the removal of the breast and other nearby tissue is referred to as a mastectomy. There are several types of mastectomies performed including double mastectomies, where both breasts are removed.[7]

Chemotherapy—Breast cancer cells may be killed or reduced with drugs taken orally or intravenously

Radiation therapy—High-energy rays are used to eliminate cancer cells.

Biological therapy—Treatment boosts an individual’s immune system to fight cancer cells.

Hormonal therapy—Hormone therapy works by blocking hormones that stimulate cancer cell growth.

Currently in the United States, one in eight women will develop breast cancer in her lifetime. If diagnosed and treated early, chances of survival are excellent. Detection through self-examination and periodic mammograms remains the first line of defense against the disease.