Genetics and Breast Cancer. Elly Lynch, Senior Genetic Counsellor Manager, Austin Health Clinical Genetics Service

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1 Genetics and Breast Cancer Elly Lynch, Senior Genetic Counsellor Manager, Austin Health Clinical Genetics Service

2 Overview Background/Our Team What is the difference between sporadic/familial cancer? How common is an inherited predisposition to cancer? How is genetic risk assessed? What is genetic testing? What are the implications of genetic testing?

3 Victorian Cancer Action Plan Action Area 1 Expanding access to genetic screening and new diagnostic technology, especially for those living in rural and regional areas. Funding provided for four Familial Cancer Centres each with regional areas of responsibility: Austin Health Monash Medical Centre Royal Melbourne Peter Mac

4 Current Austin Health Clinics Austin Familial Breast/Ovarian Cancer Clinic Austin Familial Bowel Cancer Clinic Regional Familial Cancer Clinics Albury/Wodonga, Shepparton, Ballarat Neurogenetic Clinic Endocrine/General Genetic Clinic Paediatric Genetic Clinic

5 Our Team

6 Risk/protective factors for cancer Age Increasing Environmental smoking sun exposure chemical exposure Hormonal Lifestyle Genetic menarche diet family history breast feeding alcohol hormone usage weight/activity

7 All cancers are genetic BUT Only 5-10% of cancers are due to the inheritance of a single cancer susceptibility gene

8 * 1 st cell conceptus * 1 st cell conceptus * * Breast cell * ** * * Sporadic cancer * ** ** ** * Inherited predisposition

9 How much of breast and ovarian cancer is hereditary? Hereditary 5-10% Hereditary 10-15% Familial Clustering 15-20% Breast cancer Ovarian Cancer

10 Causes of Hereditary Susceptibility to Breast Cancer Other genes / unknown 35% BRCA1 28% BRCA2 15% Other genes / unknown 5% BRCA2 37% BRCA1 80% Families with breast cancer only Families with breast / ovarian cancer

11 Causes of Hereditary Susceptibility to Ovarian Cancer 10% Hereditary HNPCC genes 7% Unknown genes <5% BRCA2 <15% 10% Br/Ov <5% Ov only BRCA1 75% 65% Br/Ov 10% Ov only

12 Other Genes Causing Hereditary Breast Cancer Tp53 (Li-Fraumeni syndrome) PTEN (Cowden syndrome, +) STK11 (Peutz-Jeghers syndrome) CHD1 (HDGC & Lobular Br Ca) ATM (Ataxia-Telangiectasia) PALB2 (Li-Fraumeni variant) CHEK2 BRIP1 (Fanconi anaemia) Other genes/unknown 35%

13 mitochondrion cytoplasm ribosomes nucleus chromosome

14 Human Karyotype BRCA2 13q12.3 BRCA1 17q21

15 BRCA1 & BRCA2 Everybody (Males & Females) have two copies of BRCA1 & BRCA2 Usually BRCA1 & BRCA2 are tumour suppressor genes involved in controlling cell growth. A BRCA1 or BRCA2 pathogenic change causes a copy of the gene to not function as it should and leads to an increased risk for breast & ovarian cancer. BRCA1 and BRCA2 changes are inherited in an autosomal dominant manner.

16 How do we assess risk? Sarah is 35. Her mother has recently been diagnosed with breast cancer at the age of 63. Sarah is concerned about her risk.

17 Evaluating Family History Approximately 20% of people have a family history of cancer which may be due to Coincidence Common environmental and lifestyle factors Genetic Factors

18 Family History our tool for assessing risk 3 generations (on each side of the family) Include first and second degree relatives Note Site of cancer Age of onset

19 Clues to Familial Breast Cancer Multiple individuals with cancer in family Age of onset and site of primary cancer Patterns of certain types of cancers (Breast & Ovarian; Prostate) Autosomal dominant inheritance Ethnicity Ashkenazi Jewish Pathology Family histories constantly evolve

20 Helpful Resources NBCC Guidelines from

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25 Risk Assessment for unaffected Average risk individual Moderately increased risk High risk

26 Sarah One FDR Dx>50 Category 1 Sarah is at or slightly above average risk 2 Dx 63

27 Sarah s Paternal Family History High Risk Features -Early age at dx D. Ovarian Ca 54y Dx Prostate ca 68yr -Presence of Ovarian & Breast Ca -Autosomal dominant fhx Dx Br Ca 38yrs Dx 63

28 Genetic Testing Mutation Detection Testing: BRCApro cut-off of 10% or higher (high risk families) Requires a living affected family member in most cases Sequencing & MLPA Approx 2 months for result If mutation found: Increased risk for second primary cancer breast & ovarian Predictive testing available for at-risk relatives. If no mutation found: Remain at high risk possibility undiscovered genetic cause Surveillance recommended Predictive testing not available to relatives

29 Genetic Testing Predictive Testing: Available to patients at risk of having inherited a known family mutation. Targeted testing Approx 4 weeks for result. If mutation found: Increased risk for breast & ovarian cancer 50% risk of passing mutation onto children If no mutation found: Population risk for breast & ovarian cancer Cannot have passed mutation onto children

30 Autosomal Dominant Inheritance Mr A Mrs A Gene change inherited Normal gene inherited

31 Cancer risks for BRCA1 & BRCA2 Women Breast cancer 50-80% Ovarian cancer 27-44% Men Breast cancer 5-10% (background 0.1%) Prostate cancer Other reported cancers: pancreas, melanoma, uterine, colon, lymphoma

32 Management recommendations BRCA1 carriers Regular breast self examination encouraged 6-monthly clinical breast examination Annual breast MRI & mammogram Consider prophylactic mastectomy BSO from 35 Risk Reducing Medication

33 Management recommendations BRCA2 carriers Regular breast self examination encouraged 6-monthly clinical breast examination Annual MRI and mammogram Consider prophylactic mastectomy Consider BSO from 40 for Br Ca risk reduction Risk Reducing Medication

34 Benefits of testing for genes predisposing to cancer Gene testing can identify individuals who carry cancer susceptibility genes who may benefit from regular follow up enabling early detection of cancer who may undergo surgery to reduce the risk of a cancer ever developing

35 Benefits of testing for genes predisposing to cancer Gene testing can identify individuals who do not carry cancer susceptibility genes may relieve anxiety avoiding unnecessary follow up enabling the resources to be used for the benefit of gene carriers at high risk of cancer

36 Problems in testing for genes predisposing to cancer Not everyone who carries a cancer susceptibility gene will develop cancer a person who does not carry a gene will still have the population risk of developing cancer breast cancer 10% life-time risk ovarian cancer 2% life-time risk bowel cancer 5% life-time risk Psychosocial / ethical issues

37 Referral Process Referral to assess the possibility of a genetic cause for a personal and/or family history of cancer. Call patient for intake and send a Family History Questionnare (FHQ). Verify information and obtain pathology from the Victorian Family Cancer Register. Appointment to see individual / family. Assess risk for breast / ovarian cancer population, moderate or high risk Offer genetic testing if indicated Offer surveillance advice

38 Recent developments Chemoprevention/Risk Reducing Medication Testing at the time of diagnosis Targeted therapies for BRCA carriers Angelina Jolie

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40 Contact Details Location: Austin Clinical Genetics Department Repatriation Campus Level 1, Building 6 Phone: Fax: genetics@austin.org.au