risk factors

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Personal History

  • The most significant risk factors for breast cancer are gender (being a woman) and age (growing older) 

Family History

  • A woman’s risk of breast cancer nearly doubles if she has a first-degree relative (mother, sister, daughter) who has been diagnosed with breast cancer 
  • Less than 20% of women who get breast cancer have a family member who has been diagnosed with breast cancer

Genetic Factors

  • About 5-10% of breast cancers may be caused by inherited gene mutations (abnormal changes passed through families)  
  • Mutations  of the BRCA1 and BRCA2 genes are the most  common mutations 
  • Women with a BRCA1 mutation have a 55-65% lifetime breast cancer risk
  • For women with a BRCA2 mutation, the lifetime risk is 45%
  • These mutations are also associated with an increased risk of ovarian cancer

Biological Factors

  • For African Americans, cytokines (leptin and adiponectin) maybe linked to overweight, obesity, and breast cancer risk 
  • Leptin is secreted into the circulation  where it functions to affect appetite control
  • Leptin may also function as a growth factor for cancer  

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Body Weight

  • Gaining weight in adulthood increases the risk of breast cancer before and after menopause
  • Women who gain about 20 pounds after age 18 have a 15% higher risk of breast cancer compared to women who gained little or no weight    

Cigarettes

  • Smoking causes a number of diseases and is linked to a higher risk of breast cancer in younger, premenopausal women 
  • There may also be link between very heavy second-hand smoke exposure and breast cancer risk in postmenopausal women  

Exercise

  • Physically active women have a lower risk (about 12%) of breast cancer than inactive women 
  • Physical activity is associated with a reduced risk of breast cancer in both premenopausal and postmenopausal women 
  • The evidence for an association is stronger for postmenopausal breast cancer 
  • Women who increase their physical activity after menopause may also have a lower risk of breast cancer than women who do not    

Alcohol

  • Alcohol can increase levels of estrogen and other hormones associated with hormone-receptor-positive breast cancer 
  • Alcohol also may increase breast cancer risk by damaging DNA in cells 
  • Compared to women who don't drink at all, women who have three alcoholic drinks per week have a 15% higher risk of breast cancer

DEFINITIONS

Breast Cancer

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Cells in the breast divide and grow without their normal control.

Ductal Carcinoma in Situ (DCIS)

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Abnormal cells grow inside the milk ducts, but have not spread to nearby tissue. 

Invasive Breast Cancer

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Cancer cells spread to nearby tissue.  

Metastatic Breast Cancer

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Invasive breast cancer that spreads to other parts of the body.    

Lymph Nodes

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Small clumps of immune cells that act as filers for the lymphatic system.

Auxiliary lymph nodes in the underarm are the first place that breast cancer spreads.



Stages of Breast Cancer

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Stage 0

  • Non-invasive breast cancers such as ductal carcinoma in situ  
  • No evidence of cancer cells or non-cancerous abnormal cells in the breast or invading neighboring normal tissue   

Stage 1

Invasive breast cancer invading normal surrounding breast tissue


Stage 1A 

Invasive breast cancer 

  • Tumor Size: 2 centimeters without  cancer outside the breast 
  • Lymph Nodes: no involvement  

 

Stage 1B

Invasive breast cancer 

  • Tumor Size: no tumor in the breast 
  • Lymph Nodes: small group of cancer cells larger than 0.2 millimeter but not larger than 2 millimeters in the lymph nodes 

or   

  • Tumor Size: not larger than 2 centimeters
  • Lymph Nodes: small groups of cancer cells larger than 0.2 millimeter but not larger than 2 millimeters in the lymph nodes  

Stage 2

Stage 2A

Invasive breast cancer 

  • Tumor Size: no tumor in the breast
  • Lymph Nodes: cancer cells larger than 2 millimeters in 1 to 3 axillary lymph nodes or in the lymph nodes near the breast bone 

or  

  • Tumor Size: larger than 2 centimeters but not larger than 5 centimeters 
  • Lymph Nodes: cancer that has not spread to the axillary lymph nodes  

or

  • Tumor Size: 2 centimeters or smaller 
  • Lymph Nodes: cancer that has spread to the axillary lymph nodes  


Stage 2B

Invasive breast cancer 

  • Tumor Size: larger than 2 centimeters but no larger than 5 centimeters
  • Lymph Nodes: small groups of breast cancer cells larger than 0.2 millimeter but not larger than 2 millimeters in the lymph nodes 

or  

  • Tumor Size:  larger than 2 centimeters but no larger than 5 centimeters 
  • Lymph Nodes: cancer that has spread to 1 to 3 axillary lymph nodes or to lymph nodes near the breastbone 

or  

  • Tumor Size: larger than 5 centimeters 
  • Lymph Nodes: cancer that has not spread to the axillary lymph nodes


Stage 3

Stage 3A

Invasive breast cancer 

  • Tumor Size: no tumor in the breast or the tumor may be any size 
  • Lymph Nodes: cancer in 4 to 9 axillary lymph nodes or in lymph nodes near the breastbone 


or  

  • Tumor Size: larger than 5 centimeters 
  • Lymph Nodes: small groups of breast cancer cells larger than 0.2 millimeter but not larger than 2 millimeters in the lymph nodes 

or  

  • Tumor Size: larger than 5 centimeters 
  • Lymph Nodes: cancer that has spread to 1 to 3 axillary lymph nodes or to the lymph nodes near the breastbone 

Stage 3B

Invasive breast cancer 

  • Tumor Size: any size that has spread to the chest wall and/or skin of the breast and caused swelling or an ulcer 
  • Lymph Nodes: cancer that has spread to up to 9 axillary lymph nodes or may have spread to lymph nodes near the breastbone  


Stage 3C

Invasive breast cancer 

  • Tumor Size: may have no sign of cancer in the breast or, if there is a tumor, it may be any size and may have spread to the chest wall and/or the skin of the breast 
  • Lymph Nodes: cancer that has spread to 10 or more axillary lymph nodes or to lymph nodes above or below the collarbone, axillary lymph nodes, or to lymph nodes near the breastbone   

Stage 4

Invasive breast cancer at first diagnosis or a recurrence of a previous breast cancer 

  • Lymph Nodes: cancer that has spread beyond the breast and nearby lymph nodes to other parts of the body:
  • Lungs
  • Bones
  • Liver
  • Brain

Triple Negative Breast Cancer (TNBC)

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Breast cancer cells that are negative for estrogen receptors (ER-), progesterone receptors (PR-), and HER2 (HER2-). 


For TNBC, the growth of the cancer is not supported by the hormones estrogen and progesterone, 

nor by the presence of too many HER2 receptors.  


  • 10-20% of breast cancers — more than one out of every 10 — are TNBC 
  • TNBC is more likely to occur before age 40 or 50 
  • African American and Hispanic women are more diagnosed with TNBC 
  • Black women are 3 times more likely to develop TNBC
  • Young women diagnosed before age 50 with a BRCA1 mutation are at risk for TNBC  
  • TNBC is treated with surgery, radiation therapy, and/or chemotherapy; but it does not respond to hormonal therapy (such as tamoxifen or aromatase inhibitors) or therapies that target HER2 receptors, such as Herceptin (Trastuzumab)  

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Survivor

For breast cancer, a person is considered to be a survivor from the time of diagnosis until the end of life.  

Facts

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1 in 8

  • About 1 in 8 U.S. women — 12.4% — will develop invasive breast cancer over the course of her lifetime 
  • Breast cancer is the most commonly diagnosed cancer among American women 
  • 30% of cancers diagnosed in women are breast cancers   

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2017-2018 Estimates

  • 255,180 cases of invasive breast cancer  
  • 63,410 cases of ductal carcinoma in situ 
  • 40,610 deaths 
  • 3.1 million survivors   

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Racial/Ethnic Disparities

  • Breast cancer is more common in African American/Black women under 45 years of age than in white women
  • African American/Black women are 42% more likely to die of breast cancer than white women
  • African American/Black women are also more likely to be diagnosed with breast cancer at later stages 
  • African American/Black women experience delays in treatment of two or more months after initial diagnosis  

Higher death rates among African American/Black women may be due to:  

  • Differences in stage at diagnosis 
  • Comorbidities (especially heart disease and diabetes) 
  • Obesity/oveweight rates 
  • Tumor characteristics 
  • Timely access to screening, diagnostic, and treatment services

FIGURES

Incidence

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The number of women diagnosed with breast cancer each year.  


The year 2014 is the most recent year for which numbers have been reported. 

The breast cancer incidence rate is grouped by race and ethnicity.   


According to the Centers for Disease Control and Prevention, in 2014, 

White women had the highest rate of getting breast cancer, 

followed by Black, Hispanic, Asian/Pacific Islander (A/PI), and American Indian/Alaska Native (AI/AN) women.


    Graph Data *Rates are the number of cases per 100,000 persons and are age-adjusted to the 2000 U.S. standard population (19 age groups – Census P25–1130).  ¶ Data are compiled from cancer registries that meet the data quality criteria for all invasive cancer sites combined for all years, 1999–2014 (covering approximately 97% of the U.S. population).  §Invasive cancer excludes basal and squamous cell carcinomas of the skin except when these occur on the skin of the genital organs, and in situ cancers except urinary bladder.  

Mortality

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The number of women who die from breast cancer each year.  


The year 2014 is the most recent year for which numbers have been reported. 

The breast cancer incidence rate is grouped by race and ethnicity.   


 

According to the Centers for Disease Control and Prevention, in 2014, 

Black women were more likely to die of breast cancer than any other group, 

followed by White, Hispanic, Asian/Pacific Islander, and American Indian/Alaska Native women.   


Graph Data *Rates are the number of deaths per 100,000 persons and are age-adjusted to the 2000 U.S. standard population (19 age groups – Census P25–1130).  †Race categories are not mutually exclusive from Hispanic origin. Rates are not presented for persons of unknown or other race.  §Data are from the National Vital Statistics System (NVSS).