302: Genetics of cancer: couselling/ethics

Question 1

What are the benefits of genomic testing?

Answer 1

-Identify the cause of disease
-Prevention and risk-reduction
-Reproductive options
-Relief from uncertainty
-Treatment decisions

Question 2

What is the definition of penetrance of genes?

Answer 2

Penetrance is the likelihood that a specific gene mutation will manifest as disease in an individual

Breast cancer susceptibility genes follow autosomal dominant inheritance with incomplete penetrance

Eg.
-Females with a BRCA1 mutation have a 75% lifetime risk of breast cancer
-For men the penetrance is lower – 15% lifetime risk of prostate cancer

Question 3

What are some ‘red flag’ features of cancer?

Answer 3

-Multiple tumours
-Tumour type: triple negative cancer, high grade cancer
-Ethnicity: Jewish, Eastern European
-Tumour associations
-Young age

Question 4

Which tools asses risk of cancer in UK?

Answer 4

Tools most commonly used in UK currently:
-Manchester scoring system
-BOADICEA/CanRisk

Other less commonly used tools:
-Tyrer-Cusick/IBIS model
-Gail model
-Claus
-BRCAPro

Question 5

How does the Manchester scoring system work?

Answer 5

Uses family history information to calculate probability of finding a pathogenic BRCA1 or BRCA2 mutation

Updated pathology-adjusted model (2009) incorporates tumour histology and hormone receptor status

Advantage of being relatively quick and simple to use in a clinical setting

UK NICE CG164 recommends BRCA1 and BRCA2 testing in individuals with a carrier probability of ≥10% which equates to a score of ≥15

Question 6

What are the 4 medical ethics?

Answer 6

Autonomy: Considering patient’s views regarding his or her treatment

Justice: Doing what is right and fair. Equity of care

Beneficence: The healthcare professional’s duty to act in a way to benefit his or her patient. Duty to do good

Non-maleficence: The healthcare professional’s duty to not harm the patient