Why is it so important to diagnose Lynch Syndrome?
People with Lynch syndrome carry an increased risk of developing some types of cancers, particularly at a younger age. Knowing about Lynch means patients can take steps including prevention, surveillance, and prophylactic surgery to reduce their risk of developing Lynch-associated cancers.
Lynch syndrome is a genetic, inherited cancer syndrome in females causing mainly bowel and endometrial cancer. Other cancers also include ovarian, stomach, skin, urinary tract cancers, breast, bladder, small intestine, kidney, pancreatic and prostate.
Having Lynch syndrome does not mean it is absolutely certain you will be diagnosed with cancer—just that your likelihood of developing the above cancers is significantly higher.
For example, Cancer Australia reports about 1 in 3 women with Lynch syndrome will develop endometrial cancer before the age of 70 years (compared to about 1 in 100 in the general population).
It is important to know if you have Lynch syndrome because a missed Lynch diagnosis can potentially cause you or a close relative (son, daughter sibling) cancer requiring treatment that could have been prevented or the cancer could have been detected earlier.
First-degree relatives with Lynch syndrome
First-degree relatives (children, siblings) of Lynch patients have a 50% risk to also carry Lynch Syndrome.
Upon confirmation of Lynch syndrome in a patient, their first-degree relatives should also consider genetic testing, even if they have never been diagnosed with cancer before.
This is important, because family members will then have the chance to learn whether they also have a greater risk of developing these cancers. This knowledge means that these family members can reduce that risk by undertaking preventative action and completing surveillance plans aimed at detecting cancer at an early stage.
How to diagnose Lynch syndrome
I routinely request Lynch testing in all patients with endometrial cancer irrespective of age or family history.
This is because if we tested only patients with a positive family history, we would miss 50% of patients with Lynch syndrome who do not carry a family history.
The first step to diagnose Lynch is an immunohistochemical test that can be done from the surgical specimen from the original uterine or bowel cancer specimen. This test is not diagnostically certain, however if the test is positive, confirmatory genetic testing should be instigated and requires a blood or sputum test. Referral to a Family Cancer Clinic or a clinical geneticist is then recommended.
Who should be tested?
Testing for Lynch Syndrome should be offered if you:
- are newly diagnosed with bowel or endometrial cancer
- are diagnosed with more than one Lynch-associated cancer
- diagnosed before 50 years of age with a Lynch-associated cancer
- have a first-degree relative affected by Lynch Syndrome.
Manage your risk of Lynch-associated cancer
Prevention, surveillance and prophylactic surgery may be possible depending on the type of cancer. For example, an annual screening for bowel cancer via colonoscopy is reliable and recommended from age 25.
For gynaecological cancers, including endometrial or ovarian cancer, unfortunately there are no reliable screening methods. Prophylactic surgery (total hysterectomy, bilateral salpingo-oophorectomy) is the most effective strategy to prevent gynaecological cancer in women who completed their family.
To manage the risk of developing endometrial cancer, we recommend yearly endometrial sampling (Pipelle) with or without a levonorgestrel intrauterine device.
If surgery is not an option, taking the oral contraceptive pill will decrease the risk of ovarian cancer risk by 50%. For more information on managing your risk of gynaecological cancers associated with Lynch Syndrome, read the Lynch Syndrome treatment page.
If you have a Lynch syndrome diagnosis and would like to discuss your risk-reducing options for gynaecological cancer, please contact me.