Genetics of Cancer


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Talia Donenberg of Sylvester Comprehensive Cancer Center discussed the genetics of cancer prevention at the 2011 WellBeingWell Conference in Miami.

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Genetics of Cancer

  1. 1. Talia Donenberg, M.S., C.G.C. Board Certified Genetic Counselor Center for Cancer Prevention and Genetics University of Miami/Jackson Health System Can we prevent cancer?
  2. 2. <ul><li>Understanding Hereditary risk </li></ul><ul><ul><li>Who is at high risk? </li></ul></ul><ul><li>Genetic testing </li></ul><ul><ul><li>When is it helpful? How does it help? </li></ul></ul><ul><ul><li>Implications of genetic testing </li></ul></ul><ul><ul><li>How can we apply this knowledge to </li></ul></ul><ul><ul><li>early detection, prevention and/or treatment ? </li></ul></ul>The genetics of cancer predisposition
  3. 3. These are the most powerful weapons in the battle against cancer Risks are much higher than the general population risk Hereditary Risk: Why do we need to know? <ul><ul><ul><li>Genetic knowledge </li></ul></ul></ul><ul><ul><ul><li>early detection </li></ul></ul></ul><ul><ul><ul><li>risk reduction strategies </li></ul></ul></ul><ul><ul><li> PREVENTION! </li></ul></ul>
  4. 4. About 2-15% of most adult cancers have a strong inherited basis How Common is Hereditary Cancer?
  5. 5. Lynch HT et al. JSO 2005 Importance of Family History
  6. 6. <ul><li>List relatives with Cancer </li></ul><ul><ul><li>Age diagnosed </li></ul></ul><ul><li>Identify Primary Site </li></ul><ul><li>Clarify “female” cancers </li></ul><ul><li>Clarify benign conditions </li></ul><ul><li>Collect Medical Records </li></ul>Sifting through the family tree
  7. 7. When to Suspect an Inherited Cancer Syndrome <ul><li>Cancer in 2 or more close relatives (same side of family) </li></ul><ul><li>Early age at diagnosis (under 50) </li></ul><ul><li>Multiple cancers in one person </li></ul><ul><li>Bilateral or rare cancers </li></ul><ul><li>Combination of cancers consistent with known syndrome (eg, colon-uterine; breast/ovarian) </li></ul><ul><li>Consistent with known patterns of inheritance </li></ul>
  8. 8. Indication for Genetic Counseling <ul><li>Male Breast Cancer </li></ul><ul><li>Pheochromocytoma </li></ul><ul><li>Medullary Thyroid Cancer </li></ul><ul><li>Adreno-cortical cancer </li></ul><ul><li>20+ Colon Polyps </li></ul><ul><li>Bilateral Cancers </li></ul><ul><li>Breast Cancer < 45 </li></ul><ul><li>Colon Cancer <45 </li></ul><ul><li>Uterine Cancer <45 </li></ul><ul><li>Sarcoma <40 </li></ul><ul><li>Any Ovarian or Fallopian Tube Cancer </li></ul><ul><li>Multiple primaries </li></ul>Without Family History
  9. 9. Genetic Counselors can help with: <ul><li>Evaluate: family history, medical records, assess risks </li></ul><ul><li>Educate: Basics of inheritance and cancer syndromes </li></ul><ul><li>Order: Appropriate genetic testing (Identify best person to test) </li></ul><ul><li>Interpret : genetic test results </li></ul><ul><li>Help: families understand /make decisions about medical options </li></ul>
  10. 10. If your personal or family history suggests an inherited cancer syndrome How is gene testing done? <ul><li>Genetic Counseling </li></ul><ul><li>Informed Consent </li></ul><ul><li>Collect DNA </li></ul><ul><li>Mouthwash or blood sample </li></ul>
  11. 11. Medical Management Options Positive Genetic Test result Possible testing for other adult relatives Increased surveillance Prophylactic surgery Lifestyle changes Chemo- prevention
  12. 12. <ul><li>10% of women are diagnosed with breast cancer </li></ul><ul><li>20% have a family member with breast cancer </li></ul><ul><li>5-8% have a gene mutation </li></ul><ul><li>2-3% have a strong family history </li></ul>Breast Cancer Statistics Breast Cancer 15-20% 5%–8% Sporadic Hereditary Family clusters
  13. 13. Breast Cancer Genes BRCA1 BRCA2 Other Genes
  14. 14. Hereditary Breast/Ovarian Cancer Syndrome <ul><li>Breast Cancer (under 50) 80% </li></ul><ul><li>Bilateral Breast Cancer 60% </li></ul><ul><li>Ovarian Cancer 20-60% </li></ul><ul><li>Breast and ovarian in the same person </li></ul><ul><li>Male Breast Cancer 1-6% </li></ul><ul><li>Prostate Cancer 20-30% </li></ul><ul><li>Pancreatic Cancer 4-7% </li></ul><ul><li>Ethnic backgrounds </li></ul><ul><ul><li>Eastern/Central European Jewish, Bahamian , Polish, French Canadian </li></ul></ul>BRCA1/BRCA2 lifetime risk
  15. 15. What options do BRCA carriers have? <ul><ul><ul><li>Begin screening with more thorough tests at earlier ages </li></ul></ul></ul><ul><ul><ul><ul><li>Breast MRI, Ultrasound for ovaries </li></ul></ul></ul></ul><ul><ul><ul><li>Consider medications to reduce cancer risks </li></ul></ul></ul><ul><ul><ul><ul><li>Tamoxifen and Evista (breast) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Birth Control Pills (ovarian) </li></ul></ul></ul></ul><ul><ul><ul><li>Consider surgical prevention </li></ul></ul></ul><ul><ul><ul><ul><li>Ovaries 96% risk reduction </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Mastectomy 95% risk reduction </li></ul></ul></ul></ul><ul><ul><ul><li>Encourage other family members to seek counseling </li></ul></ul></ul><ul><ul><ul><li>Enroll in research studies </li></ul></ul></ul>
  16. 16. Targeted Treatment for Hereditary cancers <ul><li>Platinum agents </li></ul><ul><ul><li>Ovarian cancer studies show better survival in BRCA carriers (Cass et al 2003) </li></ul></ul><ul><ul><li>Preliminary breast studies show high percentage of response in neoadjuvant studies (Byrski et al) </li></ul></ul><ul><li>PARP-1 inhibitors </li></ul><ul><ul><li>Clinical trials for both breast and ovarian cancer </li></ul></ul><ul><li>Combination Platinum and Parp-1 inhibitors </li></ul>
  17. 17. Colon Cancer: General Population vs High risk <ul><li>6% general population risk </li></ul><ul><li>20% of people with colon cancer have family history </li></ul><ul><li>5-10% of colon cancer results from strong inherited susceptibility </li></ul><ul><li>Screening colonoscopy: </li></ul><ul><li>Family history of colon cancer </li></ul><ul><ul><ul><li>If no gene involved, then start </li></ul></ul></ul><ul><ul><ul><li>10 years under earliest diagnosis in family </li></ul></ul></ul>
  18. 18. Lynch Syndrome: hereditary colon cancer syndrome <ul><li>Early but variable age at CRC diagnosis (~45 years) </li></ul><ul><li>Early Age onset Polyps <40 </li></ul><ul><li>Tumor site in proximal colon predominates </li></ul><ul><li>Extracolonic cancers : endometrium, ovary, stomach, urinary tract, small bowel, bile ducts, sebaceous skin tumors </li></ul>
  19. 19. Lynch Syndrome: Cancer risks Aarnio M et al. Int J Cancer 64:430, 1995 % with cancer 100 80 60 40 20 0 20 40 60 80 0 Age (years) Colorectal 80% Endometrial 40-60% Stomach 19% Biliary Tract 18% Urinary Tract 10% Ovarian 12%
  20. 20. Lynch Syndrome: Screening <ul><ul><li>Colonoscopy at 20-25 every 1-2 yrs </li></ul></ul><ul><ul><li>Gynecologic screening (uterus and ovaries) </li></ul></ul><ul><ul><ul><li>Ultrasound annually at 25-30 annually </li></ul></ul></ul><ul><ul><ul><li>CA-125 annually </li></ul></ul></ul><ul><ul><li>Upper endoscopy every 3 years </li></ul></ul><ul><ul><li>Urine cytology and ultrasound </li></ul></ul><ul><ul><li>Dermatologic screening </li></ul></ul>Early Detection/Cancer prevention
  21. 21. Empowering or Endangering the public? Direct to Consumer Genetic Testing: Exploiting widespread misunderstanding of genetic determinism
  22. 22. The FDA notes that patient risks include &quot;missed diagnosis, wrong diagnosis, and failure to receive appropriate treatment.&quot; Consumer watchdogs and FDA
  23. 23. <ul><li>If your family history is strong , </li></ul><ul><ul><li> more thorough testing may </li></ul></ul><ul><ul><li> be considered </li></ul></ul><ul><ul><li>New gene discoveries… </li></ul></ul>Future of genetic testing and Cancer <ul><li>Keep your family history updated </li></ul><ul><li>Follow up annually with your doctor and genetic counselor </li></ul><ul><li>Knowledge of genetics in medicine is constantly improving </li></ul>