View
507
Download
5
Category
Preview:
Citation preview
Risk Factors of Breast Cancer
Dr- Zainab A. Al-Dubisi
Contents Introduction. Epidemiology. Risk Factors. Recommendations. References.
Introduction
Breast cancer is the commonest female cancer.
The 2ndmost common cancer death in women.
The main cause of death in women ages 45- 55. 1/2cases can be explained by known risk factors.
15% are associated with +ve family history.
Cont…
Understanding the risk factors for breast cancer permits us to identify women at increased risk and intervene to modify risk, both individually and socially.
Epidemiology in KSA The recent data collected was in 2004 that by
Saudi Cancer Registry (SCR)
“Cancer Incidence Report in Saudi Arabia 2004”
It constitutes 11.5% of all cancers in Saudi. Breast cancer in female accounts for 22.4% of all
newly diagnosed cancer in female The ASR was 15.4/100,000 for female population.
The five regions with the highest ASR
Eastern region at 22.6/100,000. Riyadh region at 19.4/100,000. Makkah region at 19.1/100,000. Jouf region at 17.5/100,000 Qassim region at 12.6/100,000.
Epidemiology in U.S
The incidence of breast cancer increased during the 1980s but leveled off in the 1990s and declined between 2001 and 2003.
The current incidence is estimated at around 120/100,000 women.
Cont…
Annually: approximately 182,460 American
women are diagnosed with breast cancer.
40,480 die from the disease .
Cont…
The incidence of breast cancer is highest in developed countries:
North America & Western Europe.
Lowest incidences seen in:
South America, Africa and parts of Asia.
Survival rate The 5-year breast cancer survival rate 98%
for stage I cancer 16% for stage IV cancer 85% after 5 years 71% after 10 years 57% after 15 years 52% after 20 years www.emedicine.com
Risk Factors of Breast Cancer
Endogenous factors:
produced within or caused by the organism…
Exogenous factors:
Produced out side the body…
Endogenous factors
Age and gender. Family history and genetic factors . Race and ethnicity. Benign breast disease. Personal history of breast cancer. Hormonal & reproductive Factors. Bone & breast Density
Age & Gender
They are the strongest risk factors.
It is 100x > in female than male.
Annually, in U.S 182,460 women diagnosed with invasive breast cancers versus1900 in men.
Age
Breast cancer is rare in women< 25 y. Incidence increases with age, with a
plateau in women aged 50-55 y.
At age 75-80, the incidence decreases.
Family History
+ve family History is seen in 15-20 % of women with breast cancer.
The risk associated with having an affected 1st or 2nd degree maternal or paternal relative .
Cont… The lifetime risk is up to 4 times higher if
a mother or sister are affected.
The risk increased if: 1st degree relative affected by 1.80 fold. 2 affected 1st degree relatives, the risk
is increased 2.93 fold.
Cont…
The risk ratios were highest for women with young affected relatives.
Risk increased 2.9 fold for a woman whose relative was
diagnosed before age 30. 1.5 fold increased if the affected relative
was diagnosed after age 60. Medline ® Abstracts for References 188
of 'Epidemiology and risk factors for breast cancer
Genetics…
BRCA1, BRCA2,p53, ATM, and PTEN mutations are associated with higher risk.
Ataxia telangiectasia heterozygotes are at 4-times increased risk
Medline ® Abstracts for References.19, 189 of 'Epidemiology and risk factors for breast
cancer
Race and ethnicity
Compared with US women:
Individuals of Ashkenazi Jewish descent have a 2x greater risk.
Japanese and Taiwanese woman have
1/5 the risk.
Cont…
The highest rates occur in whites; that is
133 /100,000 The rate in blacks is 118/ 100,000 Asian Americans/Pacific Islanders is
89/100,000 American Indians/Alaska natives is
70/ 100,000 Medline ® Abstracts for
References of 'Epidemiology and risk factors for breast cancer
Cont...
Benign breast disease
Proliferative lesion:
1-without atypia (complex fibroadenoma, moderate or florid hyperplasia, sclerosing adenosis, intraductal papillomas) relative risk
1.3 to 2. (
2-with atypia (atypical lobular hyperplasia, atypical ductal hyperplasia) (relative risk 4 to 6)
Cont…
Nonproliferative lesions:
1-Single (fibrocystic change, solitary papilloma, simple fibroadenoma) are not associated with an increased risk for breast cancer.
2-Muliple may increase the risk for breast cancer modestly (1.8% at 10y-one cohort
study) . Medline ® Abstract for
Reference 25 of 'Epidemiology and risk factors for breast cancer'
PERSONAL HISTORY OF BREAST
CANCER
In Pt with personal Hx of:
Invasive breast cancer the risk of developing invasive breast cancer in the contralateral breast is 1.5% yearly.
In situ lesions the 10-year risk of developing a contralateral invasive breast cancer is 5% Medline ®
Abstract for Reference 27 of 'Epidemiology and risk factors for breast cancer'
Other Pathology
Risk is increased with Hx of ovarian cancer, endometrial cancer,
Risk is decreased with cervical cancer.
Hormonal/Reproductive Factors
Factors increasing the number of menstrual cycles increase the risk, probably due to increased endogenous estrogen exposure..
(1) Menarche < 13 years. (1) Nulliparity (2) 1st pregnancy > 30 years. (4) No breastfeeding. (5) Menopause > 50 years.
Breastfeeding
Breast feeding…
protective effect has been shown in multiple case-control and cohort studies.
The magnitude of which is dependent on the duration of breastfeeding, and on the confounding factor of parity.
Medline ® Abstracts for References 69 of 'Epidemiology and risk factors for breast cancer
Bone & Breast density
Bone density: In multiple studies, women with higher bone density had a higher breast cancer risk.
Breast density: dense breast tissue is
independently associated with an increased risk of breast cancer.
Medline ® Abstracts for References of 'Epidemiology and risk factors for breast cancer
Exogenous factors
Exogenous hormones . Weight. Socioeconomic Status. Exposure to ionizing radiation. Environment factors .
Hormonal Therapy
Long-term use of HT is associated with the highest risk. In contrast, short-term HT appears not to increase the risk of breast cancer significantly
The use of combined estrogen plus progesterone is associated with an increased relative risk of breast cancer
Weight
Obesity: Increased risk is probably due to adipose conversion of androgens to estrogens.
Cont..
Women> 80 kg have 25 % higher risk compared to those weighing< 60 kg , after adjusting for height .
BMI >33 kg/m2 has a 27% increased breast cancer risk compared to those with a BMI <21 kg/m2.
Dose the height considerer factor for breast cancer?
Yes, it dose
Cont…
Increased height has been associated with a higher risk.
Women > 175 cm tall were 20% more likely to develop breast cancer than those < 160 cm.
Medline ® Abstracts for References 33,34,45 of 'Epidemiology and risk factors for breast cancer
Seven prospective cohort studies 2000-sep-15
Socioeconomic class
Women of higher socioeconomic status are at greater risk for breast cancer.
It is independent factors that may reflect differing reproductive patterns
Medline ® Abstract for Reference 28 of 'Epidemiology and risk factors for breast cancer '
lifestylePhysical Activity Regular physical exercise appears
to provide modest protection against breast cancer particularly in premenopausal women
Medline ® Abstracts for References 46-48 'Epidemiology and risk of breast cancer
Cont…
Dietary
Red meat An association between intake of (>5 servings per week) and premenopausal breast cancer .
Cont…
Fat intake has significant impact on breast cancer risk that was suggested in a meta-analysis of studies of both premenopausal and postmenopausal women
Cont…
Alcohol intake It is associated with an increased
risk of hormone receptor-positive breast.
Medline ® Abstracts for References 'Epidemiology and risk of breast cancer
Antioxidants
There is no strong evidence for an effect of intake of vitamin E, C or beta-carotene on breast cancer risk
The data are conflicting on vitamin A and breast cancer.
Medline ® Abstracts for References 203,204f 'Epidemiology and risk factors for breast cancer
Environmental Factors
Organochlorines include polychlorinated biphenyls (PCB's), dioxins, and organochlorine pesticides such as DDT are persisting in body tissues for years
Medline ® Abstracts for References 203,204f 'Epidemiology and risk factors for breast cancer
Ionizing radiation
Ionizing radiation on the chest at a young age.10-14 yrs
Risk is seen up to 45 years & no risk after that.
Medline ® Abstracts for References 203,204f 'Epidemiology and risk factors for breast cancer
RecommendationsPrimary cancer prevention
evidence
1-Maintain a healthy weight throughout life
A - Consistent (Level 1) evidence
that overweight and obesity are significant risk factors for cancers of the breast
Contd.
2-Adopt a physically active lifestyle
A - Consistent (Level 1) evidence indicates that physical activity offers significant protection for cancers of the breast
3-Consume a healthy diet, with an emphasis on plant source
B-Limited-quality evidence suggests that plant-based diets that have high amounts of fruits, vegetables and whole grains are protective for some cancers
4-Limit consumption of alcohol
A - Consistent (Level 1) evidence exists that high alcohol intake is associated with significantly and linearly increased risk of breast cancer.
References
www.emedicine.comww.medline.comwww.cochrane.comwww.pubmed.comwww.uptodate.comwww.AAFP.com.
Swanson’s Family Medicine Textbook.
Recommended