Lynch Syndrome
Lynch syndrome (hereditary nonpolyposis colorectal cancer) is an inherited condition that substantially increases risk for colorectal, endometrial, and several other cancers. Genetic testing and aggressive screening dramatically reduce cancer mortality in affected families.
Table of Contents
Quick Facts
- ICD-10: Z80.0, Z80.4
- Inheritance: Autosomal dominant
- Main cancers: Colorectal, endometrial
Overview
Lynch syndrome is caused by mutations in mismatch repair genes (MLH1, MSH2, MSH6, PMS2, EPCAM). Affected individuals have substantially higher lifetime risks of colorectal cancer (often early onset), endometrial cancer, ovarian, stomach, urinary tract, brain, skin, and pancreatic cancers.
Diagnosis
- Family history evaluation (Amsterdam criteria, Bethesda guidelines)
- Tumor testing for microsatellite instability and mismatch repair protein loss
- Genetic testing
Management
- Colonoscopy every 1–2 years starting at age 20–25 (or earlier than youngest family case)
- Endometrial sampling and transvaginal ultrasound for women
- Annual urinalysis
- Upper endoscopy at intervals
- Consider risk-reducing hysterectomy and oophorectomy after childbearing
- Aspirin may reduce colorectal cancer risk (under specialist guidance)
- Genetic counseling for family members
When to Seek Evaluation
Consider genetic counseling if you have:
- Multiple family members with Lynch-related cancers
- Early-onset colorectal or endometrial cancer in the family
- A known Lynch syndrome mutation in your family
- Personal history of cancer with tumor testing suggesting Lynch syndrome
Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about a medical condition. If you are experiencing a medical emergency, call your local emergency number immediately.
References
- National Cancer Institute. Genetics of Colorectal Cancer.