The Role of Genetics & Your Risk of Cancer

Transcription

1 The Role of Genetics & Your Risk of Cancer January 22, 2013 Nichole Morman, MS, CGC Certified Genetic Counselor

2 Objectives Review components of genetic counseling and its importance in determining cancer risk Discuss the fundamentals of hereditary cancer genetics Recognize the most common hereditary cancer susceptibility syndromes 2

3 What is a Genetic Counselor? Healthcare professionals with specialized graduate degrees Assess hereditary cancer risk from acquired personal and family histories Provide counseling and education about cancer genetics and genetic testing Offer a course of action for managing cancer risk that seems personally appropriate (genetic testing, screening or longterm follow up) Order and interpret genetic tests Address complex psychosocial issues Facilitate entry into research studies

4 When Should Genetic Counseling Be Considered? Significant family history of cancer Reasonable likelihood of having a hereditary cancer susceptibility Genetic test results will influence medical management Patient wants information (empowerment) Ideally, test affected person first

5 All Cancer is GENETIC Not all cancer is HEREDITARY

6 Chromosomes, DNA, and Genes Cell Nucleus Chromosomes Gene Protein Adapted from Understanding Gene Testing, NIH, 1995 ASCO

7 23 pairs of chromosomes = 2 copies of every gene

8 What is Cancer? Normal body cells grow, divide, and die in an orderly fashion Cancer occurs when abnormal cells divide without control

9 Sporadic Cancer 1 st mutation Multiple mutations & environmental factors Inherited Cancer 1 st mutation (INHERITED) Multiple mutations & environmental factors

10 Most cancers are not inherited 10-15% familial 5-10% hereditary 80% sporadic

11 Clues Early age at diagnosis (<50) Clustering of cancer in 2 or more close relatives (same side of family) Bilateral/multiple cancers Multiple rare cancers Presence of linked cancers (breast and ovarian; colon and uterine) Evidence of autosomal dominant transmission (w/ sex-limited penetrance)

12 Inherited Cancer Sporadic Cancer Breast, dx 40 d. 43 Ovary, dx 45 d. 47 Prostate, dx 73 Prostate, dx 58 Breast, dx 33 Breast, dx 65

13 Breast & Ovarian Cancer

14 What is my risk? Lifetime breast cancer risk 10-12% Lifetime ovarian cancer risk 1-2% 38 38

15 Breast Cancer 10-12% lifetime risk of breast cancer 1 in 8-10 women will develop breast cancer in their lifetime Breast cancer screening Monthly Breast Self Exam (BSE) Annual Clinical Breast Exam (CBE) by physician Annual Mammogram beginning at age 40

16 Ovarian Cancer 1-2% lifetime risk of ovarian cancer 1 in women will develop ovarian cancer in their lifetime Ovarian cancer screening is available but not recommended for women at general population risk Transvaginal ultrasound CA-125 blood test

17 What is my risk? Breast, dx 55 d. 83 Breast, dx 48 Ovarian, dx 62 Lifetime breast cancer risk 29% Lifetime ovarian cancer risk 5% 38 38

18 High Risk Breast Screening Monthly self exam beginning at age 18 Clinical breast exam by physician beginning at age 25 every 6-12 months Annual mammogram and breast MRI beginning 10 years younger than the earliest breast cancer diagnosis in the family, or at age 30

19 What is my risk? Breast, dx 42 Ovary, dx 56 d. 59 Breast, dx 48 Prostate, dx 55 Lifetime breast cancer risk 56-85% 30 Lifetime ovarian cancer risk 20-60%

20 Hereditary Breast and Ovarian Cancer Syndrome (HBOC)

21 HBOC Due to mutations in BRCA1 and BRCA2 genes Increased risk for breast and ovarian cancers in addition to other cancers Red flags Multiple cases of early onset breast cancer Ovarian cancer Breast and ovarian cancer in the same woman Bilateral breast cancer Male breast cancer Ashkenazi Jewish heritage

22 BRCA1 Associated Cancers: Risk by age 70 Breast cancer 50-85% (often early age at onset) Second primary breast cancer 20%-60% Ovarian cancer 40-60% Increased risk of other cancers (eg, prostate)

23 BRCA2 Associated Cancers: Risk by age 70 breast cancer 50-85% ovarian cancer 11-20% male breast cancer 6% Increased risk of prostate, laryngeal, melanoma and pancreatic cancers (magnitude unknown)

24 HBOC Breast Cancer Screening Monthly self exam beginning at age 18 Clinical breast exam every 6 months starting at age 25 (or 5-10y before the earliest diagnosis in family) Annual mammogram and breast MRI starting at age 25 (or 5-10y before the earliest diagnosis in family)

25 HBOC Breast Cancer Risk Reduction Chemoprevention: estrogen manipulation Reduces risk for breast cancer by ~50% Efficacy in BRCA1 and BRCA2 mutation carriers? Prophylactic (preventative) mastectomy Reduces risk for breast cancer by ~90-95% PROSE study: ~2% developed breast cancer after bilateral (double) mastectomy

26 HBOC Ovarian Cancer Screening: pelvic exam, transvaginal ultrasound and CA-125 measurement NOT effective Chemoprevention: Oral Contraceptive Pills Reduces risk for ovarian cancer by ~60% Prophylactic (preventative) salpingooophorectomy Reduces risk for ovarian cancer by ~97% Recommended between age or upon completion of childbearing

27 Colorectal Cancer

28 Colorectal Cancer (CRC) 6% lifetime risk of CRC in the general population 1 in 17 individuals will develop colon cancer in their lifetime CRC screening for general population risk Annual fecal occult blood testing (FOBT) Flexible sigmoidoscopy every 5 years Colonoscopy every 10 years starting at age 50 The gold-standard in CRC screening

29 CRC Screening for Individual with Family History Parent, sibling or child with CRC at age 50 or greater: Colonoscopy beginning at age 50 and repeat every 5 years. Parent, sibling or child with CRC before age 50: Colonoscopy beginning at age 40 or 10 years younger than earliest diagnosis in family and repeat every 3-5 years. NCCN 2012 Guidelines

30 Lynch Syndrome

31 Lynch Syndrome Due to mutations in MLH1, MSH2, MSH6, PMS2, and EPCAM genes Red flags Multiple cases of early onset colon and/or uterine cancers Absence of polyposis (<10 polyps) Colon and uterine cancer in the same woman Synchronous/metachronous colon cancer Presence of other Lynch associated cancers (stomach, biliary tract, ureter, ovarian, etc)

32 Lynch syndrome: Cancer risks 100 % with cancer Colorectal 52-82% Endometrial 25-60% Stomach 6-13% Age (years) Biliary tract 1-4% Urinary tract 1-4% Ovarian 4-12%

33 Lynch Colon Cancer Screening: Colonoscopy every 1-2 years starting at age Regular colonoscopy decreases cancer risk by >50% Removal of any polyps Prophylactic (preventative) colectomy if colonoscopy cannot be performed

34 Lynch Endometrial Cancer Screening: Random endometrial biopsy NO evidence to support screening Prophylactic (preventative) hysterectomy Should be considered upon completion of childbearing Should include removal of fallopian tubes and ovaries as well

35 Genetic Testing & Possible Results

36 Possible Interpretations of Genetic Test Results Positive True Negative No Mutation Detected Uninformative Negative Variant of Uncertain Significance

37 BRCA mutation positive family Breast, dx 40 d. 43 d. 83 Ovary, dx 45 d. 47 Prostate, dx Breast, dx Unaffected Affected with cancer

38 Uninformative negative result Breast, dx 40 d. 43 d. 83 Ovary, dx 45 d. 47 Prostate, dx 58 BRCA1 and BRCA2 negative Unaffected 38 Breast, dx Affected with cancer

39 Uninformative negative result Breast, dx 40 d. 43 Other gene? d. 83 Ovary, dx 45 d. 47 Unidentifiable mutation **Research** BRCA1 and BRCA2 negative Prostate, dx Breast, dx Unaffected Affected with cancer

40 Misconceptions Insurance doesn t cover genetic testing Most insurance companies cover % of the cost of testing If someone gets testing they will be discriminated against There are laws in place to protect against genetic discrimination (health insurance, employment, etc) Its just a blood test Blood draw is only part of the genetic assessment

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