Breast Cancer Facts

What is Breast Cancer?



Breast cancer is a disease in which breast tissue cells start growing abnormally and uncontrollably.

  • The most common form of breast cancer is ductal carcinoma, which begins with cells in the breast ducts, tubes that carry breast milk to the nipple.
  • Less common forms of breast cancer include lobular carcinoma, which begins in the lobules – tissues that make breast milk – and inflammatory breast cancer, which causes the breast to become red, swollen and abnormally warm.
  • Rare forms of breast cancer include those in other types of cells (such as lymph/blood vessels or connective tissues within the breast) and breast cancer in men.
  • Additionally, patients may also be diagnosed with ductal carcinoma in situ (DCIS) or lobular carcinoma in situ (LCIS) in which cells have undergone cancerous changes but are confined within the breast duct or lobule, respectively. DCIS and LCIS are also known as breast pre-cancers or “Stage 0 breast cancer.”

Types of Breast Cancer

  • Invasive vs. in situ breast cancer: Invasive — or infiltrating — cancers spread into the surrounding breast tissue, while “in situ” breast cancers remain in their original location.

  • What is ductal carcinoma and ductal carcinoma in situ? Ductal carcinoma is the most common form of breast cancer, accounting for about one in five new breast cancer cases. Tumors form in the cells of the ducts that carry milk to the nipples. Ductal carcinoma can be either in situ (remaining in the original location) or invasive (spreading to other parts of the body). When the disease is “in situ” (DCIS), it has not spread beyond the ducts, and has a very high chance of successful treatment. Because of the risk of DCIS later becoming an invasive cancer that spreads into the surrounding breast tissue, treatment is advised for all women with the condition. Choices include careful observation to detect any future signs of cancer, as well as strategies such as medications or surgery.

  • What is lobular carcinoma and lobular carcinoma in situ? Each breast has 15 to 20 sections called lobes, and each lobe has many smaller sections called lobules. Lobules end in dozens of tiny bulbs, which produce the milk carried by the ducts. Cancer that begins in the lobes or lobules is called lobular carcinoma, and is more often found in both breasts than other types of breast cancer. Lobular carcinoma can be either in situ (remaining in the original location) or invasive (spreading to other parts of the body). When lobular carcinoma is “in situ,” it rarely becomes invasive cancer, but having LCIS in one breast increases the risk of developing invasive cancer in either breast. In invasive lobular carcinoma, cancer has spread from the lobules to surrounding normal tissue, and can also spread through the blood and lymph systems to other parts of the body.

  • What is inflammatory breast cancer? Inflammatory breast cancer (IBC) is a rare, aggressive form of breast cancer. It has some symptoms of inflammation, like swelling and redness, which are caused by cancer cells blocking lymph vessels in the skin. With IBC, a tumor might not be felt in a breast exam and may not appear on a mammogram. As a result, IBC often has already spread to distant parts of the body when it is diagnosed, making it harder to treat. IBC is a clinical diagnosis based on thickening and redness in association with a biopsy of suspicious tissue. Breast imaging tests will be conducted to determine how much of the breast tissue and how many lymph nodes are involved, and whether or not the cancer has spread to other areas of the body (metastasis).

  • What is HER2 positive breast cancer? Some women have breast tumors with higher levels of a protein known as HER2. These tumors tend to grow and spread faster than other breast cancers. Finding out the HER2 status of a breast tumor is important because there are treatments specifically targeted to this type of cancer.

  • What is triple-negative breast cancer? Triple-negative breast cancers (TNBC) are those that do not have estrogen or progesterone hormone receptors, and are also negative for the genetic HER2 marker. As a result, they can’t be treated with some of the common hormone therapies or drugs that target HER2, but chemotherapy can be helpful. TNBCs tend to occur in younger women and African-American women. They also tend to be more aggressive than other forms of breast cancer.

  • What is Paget's disease of the breast? Paget's disease is a rare type of breast cancer, representing 1-4% of all breast cancer cases. Paget’s disease is a noninvasive breast cancer that involves the skin of the nipple and usually the areola (the darker circle of skin around the nipple). Most patients with the disease also have one or more areas of ductal carcinoma in situ or invasive ductal cancer in the same breast.

What Is Metastatic Breast Cancer?

Breast cancer usually begins in the ducts that carry milk to the nipple, and can metastasize — reach other parts of the body — when the cancer cells get into the blood or lymph systems. Most of the time, cancer cells die at some point in the process of trying to spread. But, if conditions are favorable for the cancer cells, some of them are able to form new tumors in other parts of the body. Metastatic cancer cells can also remain inactive at a distant site for many years before they begin to grow again, if at all.

  • What is metastatic breast cancer to the bone? Cancer can spread to any bone in the body, but is most often found in bones near the core, especially the spine. Other common sites include the hip bone, upper leg bone, upper arm bone, ribs and the skull. Symptoms can include pain, swelling, or easy fracturing of the bones. Once the cancer is in the bone, it can rarely be cured, but treatments can shrink, stop, or slow its growth.
  • What is metastatic breast cancer to the brain? When breast cancer spreads to the brain, it tends to occur a few years after the cancer is first detected. The two most common symptoms are headaches and seizures. Generally, brain metastases are often found in younger and premenopausal women. They are also more common in women with triple negative or HER2/neu positive breast cancer. Consultation with a neurosurgeon, radiation oncologist, or medical/neuro-oncologist will determine if surgical removal or other treatment is the best choice to relieve symptoms and prolong life.
  • What is metastatic breast cancer to the liver? Symptoms of breast cancer that has spread to the liver can include yellowing of the skin or eyes, itchy skin or rash, abdominal pain, appetite loss, nausea and vomiting. While medical care may not result in a cure, a variety of treatments are available to improve the quality and length of life.

What Is Male Breast Cancer?

Breast cancer in men is very rare, with less than 1 percent of all breast cancers found in men. The risk increases for older men and those with high estrogen levels, low male-hormone levels or a family history of breast cancer. Increased risk is also associated with those who have been exposed to radiation, heavy drinkers, and those with liver disease or who are obese. Treatment options include surgery, radiation therapy, chemotherapy, hormone therapy and drugs that target genetic changes in cells that cause cancer.

What Are the Symptoms and Signs of Breast Cancer?

The most common symptoms of breast cancer include:

  • Feeling a lump in the breast area, with or without pain
  • Change in breast shape or size
  • Dimple or puckering in breast
  • A nipple turning inward into the breast
  • Nipple discharge other than breast milk, especially if it is bloody
  • Scaly, red, darkened or swollen skin in the breast area
  • Itchy, scaly sore or rash on the nipple
  • Dimple, pitted appearance or feel (similar to an orange peel) in the breast area
  • Swollen or enlarged lymph nodes around the breast area, including the collarbone and armpits

Although these symptoms can be caused by other conditions, you should check with a doctor — preferably a breast health specialist — so they can make a definitive diagnosis.

Sources: National Cancer Institute and American Cancer Society

What Increases Your Risk of Breast Cancer?

Factors that can elevate risk breast cancer risk include:

  • A personal or family history of breast cancer, including DCIS and LCIS
  • Inherited genetic predispositions, most commonly with BRCA1 or BRCA2 gene mutations
  • Elevated lifetime estrogen exposure, including:
    • Early onset of menstruation (before age 11)
    • Late-onset of menopause (after the age of 55)
    • Older age of first childbirth (after age of 30) or never having given birth
    • Taking estrogen and progesterone after menopause
  • Having dense breast tissue
  • Obesity
  • Prior radiation therapy to the chest area
  • Consuming alcohol, especially in excess of two drinks a day
  • Age: Two-thirds of invasive breast cancers are found in women 55 or older.
  • Race and ethnicity: Caucasian women are more likely to be diagnosed with breast cancer, but African American women are more likely to die from this disease. African American women are also more likely to be diagnosed at a younger age (under 45).

Research has also shown that a healthy lifestyle and maintenance of a normal weight, including a well-balanced diet and regular exercise, may reduce breast cancer risk.

Breast cancer risk may also be reduced by prophylactic methods, such as taking estrogen blockers, and undergoing a mastectomy and/or oophorectomy (surgical removal of the breasts and ovaries, respectively.) These methods are typically for women with a greatly elevated risk of developing breast cancer, such as BRCA mutation carriers.

City of Hope offers comprehensive breast cancer screening and diagnostic tools, including genetic screening and counseling. To talk to one of our patient coordinators or request an appointment, call 800-826-4673.

Sources: National Cancer Institute and American Cancer Society