SUMMARY: Lynch Syndrome. Seems to be vastly under-screened and not insignificant. Scary.

What is Lynch Syndrome?

An inherited genetic mutations which gives people an increased risk of cancer at a younger age. Also known as HNPCC (Hereditary Non-Polyposis Colorectal Cancer).

Incidence

1 in 300 to 1 in 2000 may be carriers.

Cause

Lynch syndrome is caused by a mutation in one of the body’s mismatch repair (MMR) genes. These genes are: MLH1, MSH2, MSH6, and PMS2.

Inheritance

Autosomal dominant. A parent with Lynch syndrome has a 50% (1 in 2) chance of passing on to their children.

Testing

Genetic testing for mutation.

Risk

General lifetime cancer risks for people with Lynch syndrome

• Colorectal cancer - 20% to 80%

• Stomach cancer - 1% to 13%

• Hepatobiliary cancer (liver/bile duct) - 1% to 4%

• Urinary tract (renal pelvis, ureter, bladder) cancer - 1% to 18%

• Small bowel cancer (intestines) - 1% to 6%

• Pancreatic cancer - 1% to 6%

• Brain or central nervous system tumour - 1% to 3%

Cancer risks for women with Lynch syndrome

• Endometrial cancer - 15% to 60%

• Ovarian cancer - 1% to 38%

Regular Screening

If you have Lynch Syndrome diagnosed, the following is recommended.

• Bowel - Colonoscopy every 1 to 2 years from age 25.

• Stomach - Gastroscopy every 2 years from age 30 if high risk ethnicity (Chinese, Korean, Japanese, Chilean).

• Kidneys - No regular screening. Encouraged to review if blood in urine.

• Uterus and Ovaries - Normal screening. Hysterectomy encouraged from after not having any further children or from around age 40 years.

Resources:

NSW Health - Lynch syndrome guide

Lynch Syndrome Australia - All the Lynch info

Cancer.net - Fact sheet on Lynch Syndrome

CDC - Lynch facts

EVIQ - Risk Assessment for Lynch