Lynch syndrome raises the risk of at least a dozen different cancers. Colorectal and endometrial cancers are the most common, but the syndrome also increases risk for cancers of the ovaries, stomach, small bowel, urinary tract, biliary tract, brain, skin, pancreas, and prostate. The specific risks vary significantly depending on which gene is involved.
Colorectal Cancer: The Highest Risk
Colorectal cancer is the hallmark of Lynch syndrome. Lifetime risk ranges from 30% to 74%, compared to roughly 4% in the general population. That wide range exists because Lynch syndrome isn’t one uniform condition. It’s caused by mutations in one of four DNA repair genes, and each gene carries a different level of risk.
People with MLH1 or MSH2 mutations face the steepest odds. By age 70, cumulative colorectal cancer risk reaches 40% to 52% for men and 27% to 41% for women with these mutations. MSH6 and PMS2 carriers have considerably lower risk, in the range of 10% to 20% over a lifetime. This distinction matters for screening: MLH1 and MSH2 carriers are advised to start colonoscopies at age 20 to 25, while MSH6 and PMS2 carriers can generally wait until 35.
Regardless of the gene involved, colonoscopies should be repeated every one to two years. That frequency is much more aggressive than standard screening because Lynch syndrome cancers can develop quickly from polyps.
Endometrial Cancer
For women with Lynch syndrome, endometrial (uterine) cancer is at least as likely as colorectal cancer. The lifetime risk falls between 40% and 60% for those with MLH1 or MSH2 mutations. Women with MSH6 mutations may face even higher endometrial cancer risk, with one study estimating a cumulative risk of 71% by age 70.
This makes endometrial cancer one of the most important cancers for women with Lynch syndrome to monitor. It often presents with abnormal vaginal bleeding, which can lead to earlier detection.
Ovarian Cancer
Ovarian cancer risk is elevated in women with Lynch syndrome, though not to the same degree as endometrial or colorectal cancer. The risk is highest among MLH1 and MSH2 carriers. Unlike ovarian cancers linked to BRCA mutations, Lynch syndrome-related ovarian cancers tend to occur at a somewhat younger age and may have different characteristics.
Stomach and Small Bowel Cancers
Lynch syndrome increases the risk of gastric (stomach) cancer and small bowel cancer. These are relatively uncommon cancers in the general population, which makes even a modest increase in risk significant. Screening with upper endoscopy is recommended starting between ages 30 and 40, repeated every two to four years. Starting earlier may make sense if your family has a history of upper digestive cancers.
Urinary Tract Cancers
Cancers of the urinary tract, including the renal pelvis, ureter, bladder, and kidney, are among the more underrecognized Lynch syndrome cancers. In men, urinary tract cancers are arguably the second most common Lynch syndrome cancer after colorectal. In women, they rank around fourth.
The risk varies sharply by gene. MSH2 carriers face the highest urinary tract cancer risk, with cumulative incidence reaching 17% for ureter and kidney cancer and 8% for bladder cancer by age 75. MLH1 carriers have roughly 4% to 5% risk for each. MSH6 carriers show about 3% risk for ureter and kidney cancer but 8% for bladder cancer, while PMS2 carriers have minimal risk.
An annual urine test to check for blood or abnormal cells is recommended starting at age 30 to 35, particularly for MSH2 carriers or those with a family history of urinary tract cancers.
Pancreatic and Biliary Tract Cancers
Both pancreatic cancer and cancers of the biliary tract (the bile ducts and gallbladder) occur at higher rates in Lynch syndrome families. These cancers are difficult to screen for and often detected at later stages. Pancreatic cancer screening is generally considered starting at age 50, or 10 years before the youngest diagnosis in your family, though the screening tools for pancreatic cancer remain less reliable than those for colorectal cancer.
Brain Tumors
Lynch syndrome is associated with brain tumors, most commonly glioblastoma. When Lynch syndrome occurs alongside brain tumors, this is sometimes called Turcot syndrome. These are rare even within Lynch syndrome families, but the association is well documented. Brain cancer risk is highest among MSH2 carriers.
Skin Tumors and Muir-Torre Syndrome
Lynch syndrome can cause distinctive skin tumors, particularly sebaceous adenomas, sebaceous carcinomas, and keratoacanthomas. When these skin tumors appear alongside internal cancers, the combination is called Muir-Torre syndrome, which is considered a variant of Lynch syndrome. Sebaceous adenomas are the most common of these skin lesions.
These skin tumors are unusual enough that their presence can actually serve as a diagnostic clue. If a dermatologist identifies a sebaceous tumor, it may prompt genetic testing for Lynch syndrome. Skin exams every one to two years with a professional familiar with sebaceous tumors are recommended for known Lynch syndrome carriers.
Prostate Cancer
Prostate cancer risk is elevated in men with Lynch syndrome, particularly those with MSH2 or MSH6 mutations. Annual PSA testing is recommended starting at age 40 for these men, which is earlier than standard population screening guidelines.
Cancers With Less Certain Links
Several other cancer types have been reported in people with Lynch syndrome, including breast cancer, sarcomas (such as fibrous histiocytomas, rhabdomyosarcomas, and leiomyosarcomas), and adrenocortical carcinoma. However, the evidence is not yet strong enough to confirm that Lynch syndrome directly increases the risk of these cancers. They may appear in Lynch syndrome families by coincidence or through mechanisms that aren’t fully understood. For breast cancer specifically, experts currently recommend following standard screening guidelines based on personal and family history rather than adjusting screening based on Lynch syndrome status alone.
How Risk Varies by Gene
One of the most important things to understand about Lynch syndrome is that your specific gene mutation shapes your cancer risk profile. MLH1 and MSH2 mutations carry the broadest and highest cancer risks across multiple organs. MSH6 mutations tend to carry moderate risk, with a notable tilt toward endometrial cancer in women and bladder cancer. PMS2 mutations carry the lowest overall cancer risk among the four genes, though the risk is still meaningfully higher than the general population.
This is why genetic testing results matter so much for planning surveillance. A person with a PMS2 mutation may start colonoscopies a full decade later than someone with an MLH1 mutation, and urinary tract screening may be less urgent. Knowing the specific gene allows doctors to tailor screening schedules to the cancers most likely to develop.
Aspirin as Prevention
A landmark randomized trial called CAPP2 found that daily aspirin use reduced cancer incidence in Lynch syndrome carriers. Participants who took aspirin for at least two years saw their cancer risk cut roughly in half compared to those on placebo, based on over 10 years of follow-up. The trial used 600 mg daily, though ongoing research is testing whether lower doses are equally effective. This is one of the few proven chemoprevention strategies for any hereditary cancer syndrome.