Breast Cancer Facts

Risk Factors

Nonmodifiable Risk Factors

  • Age – Risk increases with age, with a majority of diagnoses after age 50.
  • Genetic mutations – Carriers of the BRCA1 and BRCA2 genes are at increased risk for breast and ovarian cancer.
  • Family history of breast or ovarian cancer – A first-degree relative (e.g. mother, sister, daughter) or more than one family member on either side of the family with breast or ovarian cancer increases risk of breast cancer.
  • Personal history of breast cancer or other breast diseases – Women who have had breast cancer are at an increased risk of getting breast cancer again. Non-cancerous breast diseases (e.g. atypical hyperplasia, lobular carcinoma in situ) increase one’s risk of breast cancer.
  • Early menarche and late menopause – Menarche before age 12 and menopause after age 55 increases one’s exposure to hormones and raises the risk of developing breast cancer.
  • Dense breast tissue – Can prevent the detection of tumors on a mammogram
  • History of radiation exposure to breasts or chest before age 30 – Increases risk of breast cancer later on.
  • Exposure to the drug diethylstilbestrol (DES) – Directly or through their mother while in utero are at increased risk of developing breast cancer.

Modifiable Risk Factors (Risk factors that you have control over)

  • Sedentary lifestyle (not being physically active) – Can increase one’s risk of breast cancer.
  • Being overweight or having obesity after menopause – Can increase one’s risk of breast cancer.
  • Taking hormones (HRT, select oral contraceptives) – Hormone replacement therapy (HRT) taken for more than 5 years can increase one’s risk of breast cancer. Oral contraceptives (combined with estrogen and progesterone) produce a slight increase (20-30%) in breast cancer risk compared to women who have never taken the pill. This slight risk decreases upon stopping the pill and eventually returns to the same level of risk of those who have never taken the pill. Progestin-only birth control pills (mini pills) do not present an increased risk for breast cancer. (Susan G. Komen, 2022a)
  • Pregnancy history – First pregnancy after age 30, not breastfeeding, and not having a full-term pregnancy (ever) increases the risk of breast cancer.
  • Alcohol use – Alcohol use (even small amounts) is linked to an increased risk of breast cancer. Alcohol can increase the levels of circulating estrogen, which may partially explain this increased risk. (American Cancer Society, 2020; Centers for Disease Control and Prevention, 2022c)
  • Smoking – Current smokers who have been smoking for 10+ years are at a 10 percent increased risk of developing breast cancer compared to women who have never smoked. (Susan G. Komen, 2022b)
  • Changes in hormones due to night shift working – A study conducted in Poland found that night shift work increased breast cancer risk by 2.34 times (Szkiela & Kusidel, 2021).

High Risk Factors:

  • Family history of breast cancer and carrying the BRCA1 and BRCA2 genes (Centers for Disease Control and Prevention, 2022c).

Prevention (Things You Can Do to Reduce Your Risk of Breast Cancer)

  • Maintain a healthy weight.
  • Engage in physical activity every day.
  • Do not drink alcohol or limit your alcohol intake.
  • Do not use hormone replacement therapy or limit its use to less than 5 years. Speak with your doctor about replacing combination birth control pills with progestin-only options (e.g. mini pill, depo-shot) or non-hormonal options (e.g. condoms, diaphragm, cervical cap, copper IUD).
  • Choose to breastfeed.
  • Speak with your doctor about a family history of breast or ovarian cancer and get tested for BRCA1 and BRCA2 genes. (Centers for Disease Control and Prevention, 2022a)

Common Signs and Symptoms

  • A lump in the breast or underarm.
  • Change in the size of the breast.
  • Change in the shape of breast.
  • Swelling of the breast (beyond any “normal for you” cyclical changes due to menstruation).
  • Dimpling or puckering of breast skin (anywhere on the breast or nipple).
  • Pulling in of the nipple.
  • Pain in any part of the breast.
  • Itching or redness associated with the breast or nipple area.
  • Any discharge from the nipple (other than breast milk).

*Please note that these symptoms can indicate other conditions, which is why it is essential to make an appointment with a health care provider and get checked.   

(Centers for Disease Control and Prevention, 2022b)

Screening Options


A mammogram is an x-ray of the breasts. Currently, the United States Preventive Services Task Force (USPSTF) recommends the following mammography schedule:

  • Women ages 40-49 – Speak with your health care provider to assess your risk for breast cancer and determine when to get your first mammogram, as well as the frequency of subsequent mammograms.
  • Women ages 50-74 of average risk for breast cancer – Mammograms are recommended every two years (Centers for Disease Control and Prevention, 2022d).

Of note, the American Cancer Society (ACS) recommends a slightly different schedule. ACS recommends that women ages 45-55 should get a mammogram every year (American Cancer Society, 2022a).

Breast Self-Awareness/Exam

Becoming familiar with your breasts can help you recognize any changes that may be of concern. Breast self-exams (BSE) can be performed on a monthly basis. In menstruating women, a BSE should be performed just after menstruation. A comprehensive BSE includes a visual inspection of the breasts while standing, a manual inspection of the breasts while standing, and a manual inspection of the breasts while lying down.

How to perform a BSE:

  • Visual inspection – Look for any changes in breast size, shape, swelling, redness, or puckering. Raise your hands above your head and check for any changes. Put your hands on your hips and check for any changes.
  • Manual inspection while standing up – Use your three middle fingers and alternate between light, medium, and firm pressure to check each part of the breast, nipple, and armpit. Use a circular motion as your press down on the breast.
  • Manual inspection while lying down – Conduct the same exam as you did while standing up. If you like, you can add a pillow under your shoulder prior to conducting the exam.

(Cleveland Clinic, 2021)

Clinical Breast Exam

A clinical breast exam is conducted by a health care provider. A health care provider visually inspects the breasts for discoloration or redness, size, shape, and dimpling or puckering and then conducts a manual inspection of the breasts and armpit for lumps or other changes.

Other Breast Cancer Screening Tests

Breast Magnetic Resonance Imaging (MRI) – A breast MRI can be used in addition to a mammogram, particularly for women at high risk for breast cancer. An MRI uses magnets and radio waves to produce pictures of the breast (Centers for Disease Control and Prevention, 2022d).

Breast Ultrasound – A breast ultrasound is often used as an adjunct to mammography, as it can differentiate fluid-filled masses (cysts) from solid masses. It can be useful for analyzing dense breast tissue (American Cancer Society, 2022b).

Breast Biopsy – Often conducted after another screening method has flagged an area of concern. A biopsy is when tissue and/or fluid is removed from the breast to be examined more thoroughly under a microscope to check for abnormal and cancerous cells.

The primary benefit of breast cancer screening is to detect cancer early, when it is most treatable. Risks of screening can include false positive test results, false negative test results, overdiagnosis, and overtreatment.

Treatment Options

Local Treatments

Surgery – Involves cutting out cancerous tissue. Strive to remove as much cancer as possible and secure clean margins. Used to determine whether cancer has spread to the lymph nodes. Used to reconstruct the breast after a mastectomy.

Surgery types:

  • Breast-conserving surgery – Only part of the breast is removed (i.e. the cancer and part of the surrounding tissue).
  • Mastectomy – Surgery that involves the removal of an entire breast. A double mastectomy is when both breasts are removed.
  • Breast reconstruction after surgery – a. Immediate reconstruction – occurs at the same time as the breast cancer surgery. b. Delayed reconstruction – occurs at another time after breast cancer surgery.

(American Cancer Society, 2023b)

Radiation Therapy – Uses high-energy rays to target and kill the cancer cells. Types of radiation include external beam radiation therapy (EBRT) and brachytherapy. EBRT is used more often. Specifically, an external machine focuses the radiation on the area impacted by the cancer. Potential side effects include swelling of the breast, skin changes in the treated area (redness, peeling, darkening), fatigue, breast shrinkage, appearance and healing of breast reconstruction, inability to breastfeed from the affected breast, damage to nerves of the arm, and lymphedema.

Brachytherapy is commonly referred to as internal radiation. It involves the use of radioactive seeds or pellets that are placed into the breast tissue for a short period of time. Potential side effects from intracavity brachytherapy include redness or bruising at the treatment site, breast pain, infection, damage to fatty tissue, fluid collecting in the breast, and in rare cases, weakness or fracture of the ribs.

(American Cancer Society, 2021a)

Systemic Treatments

Chemotherapy – Medication is used to shrink or kill cancerous cells/tumors; it can be given intravenously (most common) or by mouth. Chemotherapy may be used before surgery, after surgery, and as the main treatment for metastatic breast cancer. Potential side effects of chemotherapy include hair loss, nail changes, mouth sores, weight changes, nausea and vomiting, diarrhea, fatigue, hot flashes, vaginal dryness, nerve damage, menstrual changes and fertility issues, problems with concentration and memory (chemo brain), and rarely, heart damage and increased risk of leukemia (due to select chemo medications).

Hormone or Endocrine Therapy – Blocks hormones (estrogen and/or progesterone) from cancerous cells/tumors. Often used after surgery for 5 years. Selective estrogen receptor modulators (SERMs), like Tamoxifen and Toremifene (Fareston), are used to block estrogen from attaching to cancer cells; thus, preventing them from continuing to grow and divide. Common side effects include hot flashes, vaginal dryness or discharge, and changes in the menstrual cycle. Rare side effects include increased risk of endometrial cancer and uterine sarcoma, blood clots, eye problems, various effects on bones. Other drugs include selective estrogen receptor degraders (SERDs) (used in women past menopause), aromatase inhibitors (AIs) (lower estrogen levels), and ovarian suppression through oophorectomy, luteinizing hormone-releasing hormone agonists, and chemotherapy drugs.

(American Cancer Society, 2023a)

Targeted Drug Therapy – Targets specific cancer cells. Usually causes less harm to normal cells compared to chemotherapy and radiation. Examples include monoclonal antibodies, tyrosine kinase inhibitors, cyclin-dependent kinase inhibitors, mammalian target of rapamycin (mTOR), and PARP inhibitors.

Immunotherapy – “Uses the patient’s immune system to fight cancer. Substances made by the body or made in a laboratory are used to boost, direct, or restore the body’s natural defenses against cancer” (National Cancer Institute, 2022).

Complementary and alternative health methods can often be safely used as an adjunct to standard cancer treatment. The American Cancer Society provides the following list of methods that are likely safe to use:

  • Acupressure
  • Acupuncture
  • Aromatherapy
  • Art therapy
  • Biofeedback
  • Labyrinth walking
  • Massage therapy
  • Meditation
  • Music therapy
  • Spirituality and prayer
  • Tai Chi
  • Yoga

(American Cancer Society, 2021b)


Recommended Sources, Clinical Trials, and Support Groups