- Guide to Breast Cancer
- Take the Breast Cancer Quiz
- Young Women & Breast Cancer
- Breast Cancer FAQs
- Patient Comments: Breast Cancer - Symptoms and Signs
- Patient Comments: Breast Cancer - Stages
- Patient Comments: Breast Cancer - Type
- Patient Comments: Breast Cancer - Treatment
- Patient Comments: Breast Cancer - Survival Rate
- Patient Comments: Breast Cancer - Diagnosis
- Find a local Oncologist in your town
- Breast cancer facts
- What is breast cancer?
- What are the statistics on male breast cancer?
- What are the different types of breast cancer? Where does breast cancer come from?
- What causes breast cancer?
- What are breast cancer risk factors? How do you get breast cancer?
- What about antiperspirants or deodorants as causes of breast cancer?
- What are breast cancer symptoms and signs?
- What tests do physicians use to diagnose breast cancer?
- What is HER2-positive breast cancer?
- What tests detect HER2?
- Do symptoms and signs of HER2-positive breast cancer differ from those of HER2-negative breast cancer?
- What are therapies for HER2-positive breast cancers?
- How are breast cancer stages determined?
- What are breast cancer treatments?
- What are breast cancer survival rates by stage? What is the prognosis of breast cancer?
- Is it possible to prevent breast cancer?
- What research is being done on breast cancer? Is it worthwhile to participate in a breast cancer clinical trial?
- I may have breast cancer. What questions should I ask my doctor?
- Is the doctor sure I have breast cancer?
- What type of breast cancer do I have?
- What difference does a precise breast cancer diagnosis make?
- What has been done to exclude cancer in other areas of the same breast or in my other breast?
- What type of medical team do I need for the most accurate breast cancer diagnosis?
- Is my family history relevant to my breast cancer diagnosis?
- What other studies should be done on my breast tissue biopsy?
- How urgent is it that I make decisions and begin breast cancer treatment?
- Should I stop taking hormone replacement therapy (HRT) after a breast cancer diagnosis?
- Even though my breast tumor does not have hormone receptors, should I take tamoxifen to reduce the risk of a new tumor?
- I have a ductal carcinoma in situ (DCIS), a type of localized cancer. Why have I been advised to have a mastectomy when other women with invasive breast cancer have lumpectomies?
- Should I start chemotherapy before surgery for breast cancer?
- If I am advised to have a mastectomy, what are the risks and benefits of immediate breast reconstruction?
- Should breast cancer patients have their lymph nodes removed?
- What is a sentinel lymph node biopsy, and what are its benefits and risks?
- Are there any other questions I should ask my doctor about breast cancer?
Quick GuideBreast Cancer Diagnosis, Symptoms, and Treatment
What causes breast cancer?
There are many risk factors that increase the chance of developing breast cancer. Although we know some of these risk factors, we don't know the cause of breast cancer or how these factors cause the development of a cancer cell.
We know that normal breast cells become cancerous because of mutations in the DNA, and although some of these are inherited, most DNA changes related to breast cells are acquired during one's life.
Proto-oncogenes help cells grow. If these cells mutate, they can increase growth of cells without any control. Such mutations are referred to as oncogenes. Such uncontrolled cell growth can lead to cancer.
What are breast cancer risk factors? How do you get breast cancer?
Some of the breast cancer risk factors can be modified (such as alcohol use) while others cannot be influenced (such as age). It is important to discuss these risks with a health-care provider anytime new therapies are started (for example, postmenopausal hormone therapy).
Several risk factors are inconclusive (such as deodorants), while in other areas, the risk is being even more clearly defined (such as alcohol use).
The following are risk factors for breast cancer:
- Age: The chances of breast cancer increase as one gets older.
- Family history: The risk of breast cancer is higher among women who have relatives with the disease. Having a close relative with the disease (sister, mother, daughter) doubles a woman's risk.
- Personal history: Having been diagnosed with breast cancer in one breast increases the risk of cancer in the other breast or the chance of an additional cancer in the original breast.
- Women diagnosed with certain benign breast conditions have an increased risk of breast cancer. These include atypical hyperplasia, a condition in which there is abnormal proliferation of breast cells but no cancer has developed.
- Menstruation: Women who started their menstrual cycle at a younger age (before 12) or went through menopause later (after 55) have a slightly increased risk.
- Breast tissue: Women with dense breast tissue (as documented by mammogram) have a higher risk of breast cancer.
- Race: White women have a higher risk of developing breast cancer, but African-American women tend to have more aggressive tumors when they do develop breast cancer.
- Exposure to previous chest radiation or use of diethylstilbestrol increases the risk of breast cancer.
- Having no children or the first child after age 30 increases the risk of breast cancer.
- Breastfeeding for one and a half to two years might slightly lower the risk of breast cancer.
- Being overweight or obese increases the risk of breast cancer.
- Use of oral contraceptives in the last 10 years increases the risk of breast cancer.
- Using combined hormone therapy after menopause increases the risk of breast cancer.
- Alcohol use increases the risk of breast cancer, and this seems to be proportional to the amount of alcohol used. A recent study reviewing the research on alcohol use and breast cancer concluded that all levels of alcohol use are associated with an increased risk for breast cancer. This includes even light drinking.
- Exercise seems to lower the risk of breast cancer.
- Genetic risk factors: The most common causes are mutations in the BRCA1 and BRCA2 genes (breast cancer genes). Inheriting a mutated gene from a parent means that one has a significantly higher risk of developing breast cancer.