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Breast Cancer Risk and Risk
Assessment Models
Jessica Ray, MS, CGC
Cancer Genetic Counselor
Ambry Genetic Laboratories
[email protected]
¡Vida! Educational Series - Promoting Good Health
Learning Objectives
• Identify Personal and Family Characteristics
that may indicate an inherited increased risk
for cancer
• Understand the role of genetic counseling in
assessing patients with possible hereditary
cancer syndromes
• Understand characteristics, advantages,
limitations, and differences of the Gail and
BRCAPRO risk-assessment tools used by
clinicians to help establish cancer risk
Who Is at “High Risk”?
• Atypia
• 5-year Gail risk >1.7%
• 2 or more 2nd-degree premenopausal
affected relatives
• Combined estrogen-progesterone hormone
therapy for more than 10 years
• Mammographically dense breasts
• Obesity
Who Is at “Very High Risk”?
•
•
•
•
•
Personal history of BC <50
BRCA1 or BRCA2 mutation carrier
2 or more 1st-degree relatives with BC
Lobular carcinoma in situ (LCIS)
Atypia and a 1st-degree relative with BC
What is Genetic Counseling?
Genetic Counseling is a
communication process that
deals with both the medical
and psychological issues
associated with the
occurrence of a genetic
disorder in a family
• Cancer genetic counseling
focuses on hereditary
cancer syndromes
• This process involves one or
more trained professionals
to help the individual or
family
Reasons for Seeking
Genetics Consultation
• To learn about
•
•
•
•
Personal risk for cancer
Children’s risk for cancer
Family’s risk for cancer
Risks for developing cancer if you have a “cancer
gene”
• Recommendations for screening, surveillance,
and/or treatment
• Educational information
• To obtain genetic DNA testing
J Med Genet 2000; 37:866-874
Key Flags that
Warrant Genetic Counseling
• Significant family medical history-breast, ovarian,
prostate, colon, uterine, melanoma, pancreatic, or other
cancers
• Cancer occurs in every generation
• Early age of onset (< 50 years)
• Male breast cancer
• Bilateral cancer, or multiple primary cancers in one
individual
• Known family genetic mutation
• Ethnicity – Ashkenazi Jewish ancestry
Sporadic, Familial or Hereditary?
• 5-10% cancers have a hereditary component
• Over 200 hereditary cancer syndromes described
• Hereditary cancer tends to occur at younger ages
than sporadic cancer, often bilateral, multifocal
• Lifetime risks of cancer exceed cancer risks due to
noninherited factors (early menarche, nulliparity,
late age of menopause, HRT, etc)
• Majority show an autosomal dominant inheritance
pattern (few are recessive)
Average Age of Diagnosis
Hereditary
• Breast
41
• Ovarian 40-50
• Prostate
63
Sporadic
• Breast
• Ovarian
• Prostate
62
60
71
Gail Model
National Cancer Institute http://www.cancer.gov/bcrisktool/Default.aspx
Gail Model: Advantages
• Identifies women who could benefit from preventive
interventions; may assist in making clinical decisions
(Determination of eligibility for tamoxifen for breast cancer risk
reduction…Gail score>1.7)
• Incorporates risk factors other than family history (eg,
reproductive variables, atypical hyperplasia, history of breast
biopsies)
• Calculation of breast cancer risk in absence of family history in
women
• Shows that BC risk increases with age and, therefore, may
prompt discussion about the importance of BC screening
• Used to counsel and educate women, especially those who
overestimate their BC risk
Gail Model: Limitations
• Not validated for black, Hispanic, and other ethnic
groups
• Only solicits family history involving first-degree
relatives
• May underestimate risk when family history is on
father’s side
• Does not take into account age at which relatives
developed BC
• Effect of number of breast biopsies (without atypical
hyperplasia) may cause inflated risk estimates
• May underestimate risk for women with demonstrated
mutations of the BRCA1 or BRCA2 genes
BRCAPRO - Advantages
• Incorporates both affected and unaffected family
members in estimation of carrier probability
• incorporates maternal and paternal breast and ovarian
cancer history
• age at cancer diagnosis, current ages, ages relatives
became deceased considered
• Ashkenazi Jewish ethnicity taken into consideration
• Oophorectomy status and breast cancer receptor status
considered
BRCAPRO - Limitations
• Dependent on published estimates of prevalence and
penetrance of BRCA1 and BRCA2
• Does not consider more distant family history past 1st
and 2nd degree relatives
• Does not consider other potential susceptibility genes
with features similar to BRCA1 and BRCA2
When Do You Offer Testing?
• American Society of Clinical Oncology recommends genetic testing :
• The individual has a personal or family history of features
suggestive of a genetic cancer susceptibility condition
• The test can be adequately interpreted
• The results will aid in diagnosis or influence the medical or
surgical management of the patient or family members at
hereditary risk of cancer
ASCO recommendations:
• Genetic testing only be done in the setting of pre-and post-test
counseling,
• Should discuss possible risks and benefits of cancer early detection and
prevention modalities
Implications/Important Points
• What do we offer individuals at high risk for
hereditary cancers who test negative for a genetic
mutation?
• Negative genetic test result does not mean No
Increased Risk!!
• AZCC High Risk Clinic for individuals at greater risk
of developing cancer
• Must continue studies to find other genes responsible
for hereditary cancers
• Must develop more advanced, individualized risk
assessment tools