Breast cancer is the second most common cancer in American women after skin cancer. It’s also the second leading cancer-related cause of death in American women after lung cancer. The good news is that today, there are about 2.9 million survivors. And the death rate has been decreasing since 1989, especially in women younger than 50. This is largely due to the success of earlier screening recommendations and increased awareness. 

Read on to learn more about breast cancer, understand the risks, and see what’s on the horizon for breast cancer research.

What Are the Types of Breast Cancer?

Breast cancers arise in the milk ducts, the lobules, or the stroma. Lobules are the milk-producing glands and stroma is all other breast tissue, including fat, connective tissue, and blood and lymph vessels. Here’s a summary of the main forms of breast cancer:

  • Noninvasive breast cancer is ductal carcinoma in situ (DCIS). Cancer cells are growing inside the milk ducts and remain in place (in situ). They have not spread or invaded other breast tissues. DCIS accounts for 20% of new breast cancer diagnoses. This is the earliest and most curable form of breast cancer.
  • Invasive breast cancer is cancer that has invaded or grown in to other breast tissues. It can also travel to tissues outside the breast. The most common one is invasive ductal carcinoma (IDC). IDC accounts for 50-75% of all breast cancers. The other main form is invasive lobular carcinoma (ILC). ILC accounts for 10-15% of breast cancers.
  • Hormone receptor-positive breast cancer is a tumor of cancer cells that have receptors for either estrogen (ER) or progesterone (PR). These tumors grow when estrogen or progesterone attach to the receptors. Blocking the receptors or reducing the amount of estrogen or progesterone starves the tumor. About two-thirds of all breast cancers are hormone-receptor positive.
  • HER2-positive breast cancer is a tumor of cancer cells that have a growth protein receptor called human epidermal growth factor receptor 2. The HER2 receptor helps the tumor grow. Immune-targeted therapies, such as monoclonal antibodies, interfere with the receptor and tumor growth. Up to 20% of breast cancers are HER2 positive.

What Are the Symptoms of Breast Cancer?

In the United States, most women learn about a breast cancer diagnosis before they have symptoms. This is because mammograms can catch breast cancers at very early stages. However, not all women get recommended annual screening mammograms, and mammograms can’t catch all breast cancers. So it’s important to know the warning signs:

  • Breast swelling or pain
  • Lymph node swelling or tenderness
  • Nipple discharge, pain, or retraction (turning inward)
  • Nipple skin changes, such as redness, scaliness or thickening
  • Skin redness or dimpling

An emerging theme in catching breast cancer before it progresses is breast self-awareness. The goal is for women to understand the normal appearance and feel of their breasts throughout the month, not just at a specific time interval. 

Who Gets Breast Cancer?

Both men and women get breast cancer, but male breast cancer is rare. The largest proportion of breast cancer diagnoses are in women 45-74 years of age, with the median age 61 years at the time of diagnosis. Male breast cancer is 100 times less common than breast cancer in women. 

What Are the Risk Factors for Breast Cancer?

A woman’s risk of developing breast cancer increases with the following risk factors:

  • Increasing age
  • First period before age 12
  • First child after age 30, or having no children
  • Family history in mother, sister or daughter
  • Personal history of breast cancer
  • Past breast biopsies showing abnormal and fast-growing cells
  • Caucasian race
  • Overweight or obesity
  • Dense breast tissue
  • Presence of BRCA/BRCA2 mutations
  • History of hormone replacement therapy for menopause
  • Previous chest radiation therapy (not X-rays)

It’s important to remember that not all women who have these risk factors develop breast cancer. If you are worried, discuss your concerns with your doctor and ask him or her for a breast cancer risk assessment.