Genetics and Cancer Care. Cynthia Forster-Gibson, MD, PhD and Loren Mackay- Loder, MSc Genetics Program, THP

Transcription

1 Genetics and Cancer Care Cynthia Forster-Gibson, MD, PhD and Loren Mackay- Loder, MSc Genetics Program, THP

2 Faculty/Presenter Disclosure Faculty: Cynthia Forster-Gibson Relationships with commercial interests: None Presenter: Loren Mackay-Loder Relationships with commercial interests: None

3 Cancer distribution Single gene cause known, 10% Sporadic; 70% Familial; 30% no known gene(s), 20%

4 How do you identify those appropriate for referral to Genetics Personal history age(s) at cancer diagnosis tumour pathology bilaterality synchronous tumours gender other organ involvement (eg. ovary, stomach, skin)

5 How do you identify those appropriate for referral to Genetics Family history tumour type, age at diagnosis, bilateral, synchronous, gender maternal and paternal relatives full and half relationships affected and unaffected individuals ethnicity (founder mutations) any limitations with the family history

6 Information to include with the referral If patient is affected Tumour pathology If patient is unaffected Details of family history (including relationship to patient, age at cancer diagnosis, cancer pathology if known If referral is based on pathogenic variant in the family Copy of family members genetic test result

7 The genetic assessment Family history reviewed Confirm pathology Determine if/what testing is appropriate Identify best testable person Review pros and cons of testing Management options (broadly)

8 Genetic testing Testing approaches Single genes Multigene panels Results Pathogenic Likely pathogenic Variant of uncertain significance -Periodic review Benign variants No variant uninformative not negative- Family history remains important Reclassification

9 New complexities of genetic testing Panel testing Increased chance of one or more VUS Positive test result that doesn t match the personal or family history Some genes of limited value/information

10 Resources THP Clinical Genetics website cs/pages/default.aspx Referral form tics/documents/3991_dhr_familial_cancer_genet ics_referral_form_fillable.pdf

11 What to discuss with your patient? Genetic factors are risk factors Clue to their presence may be personal and/or family history

12 Sporadic vs Hereditary Cancer H H ttp://

13 What to discuss with your patient? Knowledge of your genetic status may: Give you a better estimate of your specific cancer risks Determine if you need a specialized screening program for early detection Allow you to take measures (prophylactic surgery, chemoprevention) to reduce your risk Heighten (your) primary care provider s awareness of your specific cancer risks Help you understand your children s (and other family members ) risks

14 What to discuss with your patient? Genetic factors are universal risk factors Regardless of ethnic background, cultural practices They may inherited or new Your patient did not do anything to make this happen They are there from conception to death If you know about them, you may be able to decrease your risk of cancer or find it early

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16 How does ethnic variation influence testing or test interpretation? Specific pathogenic variants exist in specific ethnic groups BRCA1 and BRCA2 3 specific pathogenic variants in individuals of Ashkenazi Jewish descent specific variants in Icelanders, French Canadians, Portugese etc Our knowledge of rare variants in some ethnic groups is limited Our knowledge of cancer risk genes in some groups is limited (Filipinos, Jamaicans etc) not studied well, ethnic diversity

17 What to discuss with your patient? Barriers Evidence for reduced provincial cancer screening in some immigrant populations Reasons are complex, include cultural, physician, financial factors Language need for a translator Type of cancer

18 Factors that should influence management choices/discussions High risk gene? BRCA1, BRCA2 PTEN, STK11, CDH1, PALB2, TP53 Lynch-associated MSH2, MSH6, MLH1, PMS2, EPCAM Moderate risk gene? CHEK2 particularly with positive family history, ATM, NBN Cancer risk not necessarily clear Family History

19 How to support your healthy ( unaffected ) high risk patient Genetic factors are lifelong risk factors Decision-making will be different at different life stages Management will change over time and should be reviewed periodically NCCN n_gls/default.aspx

20 How to support your high risk patient with cancer Genetic factors may alter the treatment plan (eg. PARP inhibitors in women with ovarian cancer who have a BRCA2 pathogenic variant) There may be risks for other cancer types Decision-making will be different depending on their health status Management will change over time and should be reviewed periodically NCCN gls/default.aspx

21 Thanks! Questions?

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