Inherited Cancer: Understanding Genetic Testing and Family History
Understanding Inherited Cancer
While most cancers are sporadic (occurring by chance),
Common Hereditary Cancer Syndromes
Hereditary Breast and Ovarian Cancer (HBOC)
Caused by mutations in BRCA1 and BRCA2 genes:
- Significantly increased risk of breast and ovarian cancers
- Also increases risk of pancreatic and prostate cancers
- May warrant earlier and more frequent screening
- Preventive surgery options available
Lynch Syndrome
The most common hereditary colorectal cancer syndrome:
- Caused by mutations in mismatch repair genes
- Increases risk of colorectal, endometrial, and other cancers
- Requires earlier and more frequent colonoscopy screening
Li-Fraumeni Syndrome
A rare syndrome caused TP53:
- Very high lifetime cancer risk
- Multiple cancer types at young ages
- Requires intensive screening protocols
pecial considerations for radiation exposure
Familial Adenomatous Polyposis (FAP)
Characterized by hundreds to thousands of colon polyps:
- Nearly 100% risk of colorectal cancer if untreated
- Requires early and frequent colonoscopy
- Prophylactic surgery often recommended
Red Flags for Hereditary Cancer
Consider genetic counseling if your family has:
- Multiple relatives the same type of cancer
- Cancer diagnosed at unusually young ages
- One person with multiple primary cancers
- Rare cancers in the family
- Cancer in both sides of paired organs
- Male breast cancer
- Specific ethnic backgrounds with known founder mutations
Genetic Testing Process
Pre-test Counseling
Before testing, genetic counselors help you:
- Understand the benefits and limitations of testing
- Discuss potential results and their implications
- Consider psychological and social impacts
- Review insurance and discrimination concerns
Types of Genetic Tests
- Single gene testing: Tests for specific known mutations
- Panel testing: Tests multiple genes simultaneously
- Tumor testing: Analyzes cancer tissue for mutations
- Pharmacogenomic testing: Guides treatment selection
Understanding Results
- Positive: Harmful mutation identified
- Negative: No harmful mutation found
- Variant of uncertain significance: Unclear clinical meaning
Managing Genetic Risk
Enhanced Screening
- Earlier start age for screening
- More frequent screening intervals
- Additional screening modalities (MRI, etc.)
- Screening for multiple cancer types
Chemoprevention
- Medications to reduce cancer risk
- Tamoxifen or raloxifene for breast cancer risk
- Aspirin for colorectal cancer in Lynch syndrome
Prophylactic Surgery
- Risk-reducing mastectomy
- Risk-reducing salpingo-oophorectomy
- Prophylactic colectomy
- Careful consideration of benefits vs. risks
Family Communication
Genetic information affects the entire family:
- Sharing results with at-risk relatives
- Helping family members access genetic counseling
- Considering cascade testing for family members
- Addressing family dynamics and concerns
Psychological Considerations
- Anxiety about cancer risk
- Survivor guilt
- Impact on family relationships
- Decision-making about prevention options
- Importance of psychological support
Future Directions
The field of cancer genetics is rapidly evolving:
- Discovery of new cancer susceptibility genes
- Improved risk prediction models
- Personalized prevention strategies
- Better understanding of gene-environment interactions