Breast Cancer Risk Factors & Cancer Types

Houston Methodist breast care specialists evaluate and identify factors that may increase patients’ breast cancer risks. We ensure patients undergo the screenings needed to be diagnosed and treated as early as possible.

Additionally, our High Risk Program for breast cancer identifies and serves patients with an increased likelihood of developing breast cancer. We collaborate with primary care doctors, ob-gyns and gastroenterologists, who refer their high-risk patients for more advanced evaluation.

Breast Cancer Risks

Your doctor will recommend screenings depending on your breast cancer risk. 

Breast cancer risks include:
  • Family history of breast cancer
  • Personal history of breast or ovarian cancer
  • Personal history of noncancerous (benign) tumors and tissue removal
  • Mutations in breast cancer gene 1 (BRCA1) or breast cancer gene 2 (BRCA2)
  • Menstruation before age 12
  • Giving birth to a first child after age 30 or being childless
  • Beginning menopause after age 55
  • Aging – most cases occur after age 50
  • Consuming more than one alcoholic drink daily
  • Being overweight or obese – especially after menopause or if excess body fat is in the upper body
  • Taking birth control pills at least four years before a first, full-term pregnancy
  • Postmenopausal hormone therapy
  • Estrogen produced by the body
  • Occupational radiation exposure

Breast Cancer Types

Cancer can originate from different types of cells or tissues in the breast. Responses to treatment may differ, depending on the type, which include:
  • Ductal carcinoma in situ (DCIS) – a common, noninvasive breast cancer. Cancer cells develop in the lining of the milk ducts without spreading to nearby tissue
  • Lobular carcinoma in situ (LCIS) – an area of abnormal cell growth that increases risk of later invasive breast cancer development. It is found in the lobules, or milk-producing organs, without invading nearby tissue. Women who have had LCIS have a higher chance of developing an invasive breast cancer
  • Infiltrating ductal carcinoma (IDC) – also known as invasive ductal carcinoma, is the most common breast cancer. It starts in the milk ducts, grows into the breast’s fatty tissue and can spread to other parts of the body through the lymphatic system or bloodstream 
  • Infiltrating lobular carcinoma (ILC) – also known as invasive lobular carcinoma, starts in the lobules and can spread 
  • Inflammatory breast cancer – a less common invasive cancer that does not produce lumps or tumors. It makes the breast skin appear red and feel warm. The breast may become larger and more tender. It is hard to detect in its early stages

Breast Cancer Causes

  • Hormone receptor-positive breast cancer – receptors, or proteins, in and on breast cells pick up hormone signals telling estrogen or progesterone to grow. They are:
    • Estrogen-receptor-positive (ER+) – has estrogen receptors. Cancer cells may receive signals from estrogen that could promote growth
    • Progesterone-receptor-positive (PR+) – has progesterone receptors. Cancer cells may receive signals from progesterone that could promote growth
  • HER2-positive breast cancer – HER2, or human epidermal growth factor receptor 2, is a protein that promotes cancer cell growth. A gene mutation causes an HER2 protein excess, and breast cancer cells grow faster
  • Hormone receptor-negative and HER2-negative breast cancer – known as triple negative breast cancer, cancer cells lack estrogen and progesterone receptors and do not have excess HER2 proteins. This cancer typically spreads faster than other invasive cancers and is more common among African American and younger women

Breast Cancer Stages

During breast cancer staging, doctors examine:
  • Tumor size
  • Cancer spread to lymph nodes
  • Cancer spread to other parts of the body

Breast Cancer Phases 

  • Early breast cancer – typically stages 0 and 1. Tumors are fairly small, and cancer cells have not spread outside breast tissue
  • Locally advanced breast cancer – typically stages 2 and 3. Tumors may be larger, and cancer cells may have spread to underarm lymph nodes
  • Metastatic breast cancer – typically stage 4. Cancer cells have spread to other organs and tissues

Staging tests and procedures include:
  • Chest X-ray
  • Computed tomography (CT) scan
  • Breast magnetic resonance imaging (MRI)
  • Bone scan
  • Lumpectomy
  • Biopsy

Houston Methodist provides mammograms and breast care at the following convenient locations: