Breast Cancer
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Basics
Most commonly diagnosed cancer (CA) in women and the second most common cause of CA death for U.S. women. Females have a ~2.6% or 1 in 39 chance of dying from breast cancer in the United States.
Description
- Malignant neoplasm of cells native to the breast—epithelial, glandular, or stroma
- Types: ductal carcinoma in situ (DCIS), infiltrating ductal carcinoma, infiltrating lobular carcinoma, Paget disease, phyllodes tumor, inflammatory breast cancer (BC), angiosarcoma
Epidemiology
Incidence
- Estimated new female DCIS: 49,290; invasive BC: 281,550 in 2021
- Estimated deaths in 2021: females 43,600
- Incidence rates of BC have increased by 0.5% per year in recent years.
Prevalence
There are >3.8 million breast cancer survivors in US.
Etiology and Pathophysiology
- Genes such as BRCA1 and BRCA2 function as tumor suppressor genes, and mutation leads to cell cycle progression and limitations in DNA repair.
- Mutations in estrogen/progesterone induce cyclin D1 and c-Myc expression, leading to cell cycle progression.
- Additional tumors (33%) may cross talk with estrogen receptors and epidermal growth factors receptors (EGFR), leading to similar abnormal cellular replication.
Genetics
- Criteria for additional risk evaluation/gene testing in affected BC individual
- BC at age ≤50 years
- BC at any age and
- ≥1 family member with BC ≤50 years of age or ovarian/fallopian tube/primary peritoneal CA
- ≥2 family members with BC or pancreatic CA
- Population at increased risk (e.g., Ashkenazi Jew with BC or ovarian CA at any age)
- Triple-negative BC (ER−, PR−, HER2−)
- Two BC primaries
- Ovarian/fallopian tube/primary peritoneal CA
- ≥1 family member with BC and CA of thyroid, adrenal cortex, endometrium, pancreas, central nervous system, diffuse gastric, aggressive prostate (Gleason >7), leukemia, lymphoma, sarcoma, dermatologic manifestations, and/or macrocephaly, gastrointestinal (GI) hamartomas
- Male BC
- Criteria for additional risk evaluation/gene testing in unaffected BC individual
- First- or second-degree relative with BC ≤45 years of age
- ≥2 breast primaries in one individual
- ≥1 ovarian/fallopian tube/primary peritoneal CA from same side of family
- ≥2 w/ breast primaries on same side of family
- ≥1 family member with BC and CA of thyroid, adrenal cortex, endometrium, pancreas, CNS, diffuse gastric, aggressive prostate, leukemia, lymphoma, sarcoma, dermatologic manifestations, and/or macrocephaly, GI hamartomas
- Ashkenazi Jew with BC/ovarian CA at any age
- Male BC
- Known BC susceptibility gene mutation in a family member
- BRCA1 and BRCA2 are inherited in an autosomal fashion and account for 5–10% of female and 5–20% male CAs; 15–20% familial BCs
- Mutations higher in Ashkenazi Jewish descent
- Mutation in BRCA raises risk to 45–65% from 7% at age 70 years.
Risk Factors
- National Cancer Institute BC Risk calculator: https://bcrisktool.cancer.gov
- Hormone replacement therapy (combination estrogen-progesterone and estrogen only agents [but not vaginal estrogen]) during perimenopause increases breast cancer risk for 10 years after medication is discontinued.
- Relative risk (RR) >4.0:
- Age >65 years
- Biopsy confirmed atypical hyperplasia
- BRCA mutation
- DCIS
- Lobular carcinoma in situ (LCIS)
- Personal history of early-onset BC (<40 years)
- ≥2 first-degree relatives diagnosed at an early age
- RR 2.1 to 4.0:
- Personal history of BC (40+ years)
- Postmenopausal
- History of radiation
- First-degree relative of BC
- RR 1.1 to 2.0:
- Alcohol use
- Ashkenazi Jewish descent
- Diethylstilbestrol exposure
- Early menarche (<12 years old)
- Late menopause (>55 years old)
- High socioeconomic status
- First pregnancy at >30 years
- Proliferative breast disease without atypia (fibroadenoma or ductal hyperplasia)
- Dense breasts (>50%)
- Nulliparous/no history of full-term pregnancy
- No history of breastfeeding
- History of obesity
- History of endometrial or ovarian CA
- Hormone replacement therapy
- Recent oral contraceptive pill use
- Tall height
- Patients with 20–25% lifetime risk should receive an annual MRI beginning at age 30 years:
- BRCA mutation
- First-degree relative with BRCA mutation
- History of radiation age 10 to 30 years
- Li-Fraumeni or Cowden syndrome or first-degree relative with the same
- Patients with 15–20% lifetime risk:
- Personal history of BC, DCIS, LCIS, atypical ductal hyperplasia, atypical lobular hyperplasia
- History of dense or unevenly dense breasts
General Prevention
- Maintain healthy weight—obesity increases BC risk; physical activity and healthy diet are key.
- Limit alcohol use—≥1 serving of alcohol per day is recommended.
- High serum 25-OH vitamin D levels correlate with lower breast cancer risk; consider vitamin D supplementation.
- Medication: The U.S. Preventative Services Task Force (USPSTF) recommends that clinicians offer to prescribe risk-reducing medications, such as tamoxifen, raloxifene, or aromatase inhibitors, to women who are at increased risk for breast cancer and at low risk for adverse medication effects (B recommendation).
- The National Cancer Institute Risk Assessment Tool can be used to determine risk.
- Greater risk was defined as >3% where the risk of medication harms are low.
- Breast self-exams (BSE): American Cancer Society no longer recommend routine monthly BSE.
- Clinical breast exam (CBE):
- USPSTF: insufficient evidence to assess clinical benefits and harms
- American Cancer Society (ACS): no clear benefit or structured guidelines in average-risk women (1)
- Mammography:
- USPSTF: women should undergo biennial mammogram starting at age 50 until age 74
- American Cancer Society: Women should have annual mammograms starting at age 45 to 54, then women 55 and over should have biennial mammograms or can continue yearly screening if desired (1).
- Women ages 40 to 44 have the choice to begin annual screening mammograms if desired.
Commonly Associated Conditions
- Genetic syndromes and mutations such as BRCA1, BRCA2, Li-Fraumeni, and Cowden disease
- History of high-risk breast lesions such as atypical ductal hyperplasia (ADH), atypical lobular hyperplasia (ALH), and LCIS
- Obesity
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Basics
Most commonly diagnosed cancer (CA) in women and the second most common cause of CA death for U.S. women. Females have a ~2.6% or 1 in 39 chance of dying from breast cancer in the United States.
Description
- Malignant neoplasm of cells native to the breast—epithelial, glandular, or stroma
- Types: ductal carcinoma in situ (DCIS), infiltrating ductal carcinoma, infiltrating lobular carcinoma, Paget disease, phyllodes tumor, inflammatory breast cancer (BC), angiosarcoma
Epidemiology
Incidence
- Estimated new female DCIS: 49,290; invasive BC: 281,550 in 2021
- Estimated deaths in 2021: females 43,600
- Incidence rates of BC have increased by 0.5% per year in recent years.
Prevalence
There are >3.8 million breast cancer survivors in US.
Etiology and Pathophysiology
- Genes such as BRCA1 and BRCA2 function as tumor suppressor genes, and mutation leads to cell cycle progression and limitations in DNA repair.
- Mutations in estrogen/progesterone induce cyclin D1 and c-Myc expression, leading to cell cycle progression.
- Additional tumors (33%) may cross talk with estrogen receptors and epidermal growth factors receptors (EGFR), leading to similar abnormal cellular replication.
Genetics
- Criteria for additional risk evaluation/gene testing in affected BC individual
- BC at age ≤50 years
- BC at any age and
- ≥1 family member with BC ≤50 years of age or ovarian/fallopian tube/primary peritoneal CA
- ≥2 family members with BC or pancreatic CA
- Population at increased risk (e.g., Ashkenazi Jew with BC or ovarian CA at any age)
- Triple-negative BC (ER−, PR−, HER2−)
- Two BC primaries
- Ovarian/fallopian tube/primary peritoneal CA
- ≥1 family member with BC and CA of thyroid, adrenal cortex, endometrium, pancreas, central nervous system, diffuse gastric, aggressive prostate (Gleason >7), leukemia, lymphoma, sarcoma, dermatologic manifestations, and/or macrocephaly, gastrointestinal (GI) hamartomas
- Male BC
- Criteria for additional risk evaluation/gene testing in unaffected BC individual
- First- or second-degree relative with BC ≤45 years of age
- ≥2 breast primaries in one individual
- ≥1 ovarian/fallopian tube/primary peritoneal CA from same side of family
- ≥2 w/ breast primaries on same side of family
- ≥1 family member with BC and CA of thyroid, adrenal cortex, endometrium, pancreas, CNS, diffuse gastric, aggressive prostate, leukemia, lymphoma, sarcoma, dermatologic manifestations, and/or macrocephaly, GI hamartomas
- Ashkenazi Jew with BC/ovarian CA at any age
- Male BC
- Known BC susceptibility gene mutation in a family member
- BRCA1 and BRCA2 are inherited in an autosomal fashion and account for 5–10% of female and 5–20% male CAs; 15–20% familial BCs
- Mutations higher in Ashkenazi Jewish descent
- Mutation in BRCA raises risk to 45–65% from 7% at age 70 years.
Risk Factors
- National Cancer Institute BC Risk calculator: https://bcrisktool.cancer.gov
- Hormone replacement therapy (combination estrogen-progesterone and estrogen only agents [but not vaginal estrogen]) during perimenopause increases breast cancer risk for 10 years after medication is discontinued.
- Relative risk (RR) >4.0:
- Age >65 years
- Biopsy confirmed atypical hyperplasia
- BRCA mutation
- DCIS
- Lobular carcinoma in situ (LCIS)
- Personal history of early-onset BC (<40 years)
- ≥2 first-degree relatives diagnosed at an early age
- RR 2.1 to 4.0:
- Personal history of BC (40+ years)
- Postmenopausal
- History of radiation
- First-degree relative of BC
- RR 1.1 to 2.0:
- Alcohol use
- Ashkenazi Jewish descent
- Diethylstilbestrol exposure
- Early menarche (<12 years old)
- Late menopause (>55 years old)
- High socioeconomic status
- First pregnancy at >30 years
- Proliferative breast disease without atypia (fibroadenoma or ductal hyperplasia)
- Dense breasts (>50%)
- Nulliparous/no history of full-term pregnancy
- No history of breastfeeding
- History of obesity
- History of endometrial or ovarian CA
- Hormone replacement therapy
- Recent oral contraceptive pill use
- Tall height
- Patients with 20–25% lifetime risk should receive an annual MRI beginning at age 30 years:
- BRCA mutation
- First-degree relative with BRCA mutation
- History of radiation age 10 to 30 years
- Li-Fraumeni or Cowden syndrome or first-degree relative with the same
- Patients with 15–20% lifetime risk:
- Personal history of BC, DCIS, LCIS, atypical ductal hyperplasia, atypical lobular hyperplasia
- History of dense or unevenly dense breasts
General Prevention
- Maintain healthy weight—obesity increases BC risk; physical activity and healthy diet are key.
- Limit alcohol use—≥1 serving of alcohol per day is recommended.
- High serum 25-OH vitamin D levels correlate with lower breast cancer risk; consider vitamin D supplementation.
- Medication: The U.S. Preventative Services Task Force (USPSTF) recommends that clinicians offer to prescribe risk-reducing medications, such as tamoxifen, raloxifene, or aromatase inhibitors, to women who are at increased risk for breast cancer and at low risk for adverse medication effects (B recommendation).
- The National Cancer Institute Risk Assessment Tool can be used to determine risk.
- Greater risk was defined as >3% where the risk of medication harms are low.
- Breast self-exams (BSE): American Cancer Society no longer recommend routine monthly BSE.
- Clinical breast exam (CBE):
- USPSTF: insufficient evidence to assess clinical benefits and harms
- American Cancer Society (ACS): no clear benefit or structured guidelines in average-risk women (1)
- Mammography:
- USPSTF: women should undergo biennial mammogram starting at age 50 until age 74
- American Cancer Society: Women should have annual mammograms starting at age 45 to 54, then women 55 and over should have biennial mammograms or can continue yearly screening if desired (1).
- Women ages 40 to 44 have the choice to begin annual screening mammograms if desired.
Commonly Associated Conditions
- Genetic syndromes and mutations such as BRCA1, BRCA2, Li-Fraumeni, and Cowden disease
- History of high-risk breast lesions such as atypical ductal hyperplasia (ADH), atypical lobular hyperplasia (ALH), and LCIS
- Obesity
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