U. MELBOURNE (AUS) — New research offers a clearer picture of the cancer risks associated with Lynch syndrome.
People with Lynch syndrome have a genetic mutation that gives them a high risk of several types of cancer, including bowel cancer. The damaged genes are unable to repair any errors that occur in their DNA.
The study, published in the Journal of Clinical Oncology, confirms the increased risk of cancers already known to be associated with Lynch syndrome, including colon, uterus, ovary, kidney, stomach, and bladder cancers. The researchers also found those with Lynch syndrome faced a moderately increased risk of developing breast and pancreatic cancer.
The researchers, led by Aung Ko Win, and associate professor Mark Jenkins, at the University of Melbourne, followed 450 people with a mutation in one of the four mismatch repair genes associated with Lynch syndrome, and more than 1000 of their relatives who were not carriers of these mutations.
Study participants were evaluated every five years at recruitment centers affiliated with the Colon Cancer Family Registry in Australia, New Zealand, Canada, and the United States.
After five years, those with Lynch syndrome had a 20-fold greater risk of colorectal cancer; a 30-fold greater risk of endometrial (uterine) cancer; a 19-fold higher risk of ovarian cancer; an 11-fold greater risk of kidney cancer; a 10-fold greater risk of pancreatic, stomach, and bladder cancers; and a four-fold greater risk of breast cancer.
People with Lynch syndrome also tended to be diagnosed with these cancers at an earlier age than people in the general population.
The researchers say their findings regarding breast cancer were unexpected. They say further studies were needed to determine if ages at mammographic screening or methods such as use of MRI should be recommended for people with Lynch syndrome.
Currently, individuals with Lynch syndrome typically undergo colonoscopies at earlier ages than the general population, but no other special screening regimens have been agreed upon.
This is the largest study to date of cancer risk for non-carriers of family-specific mutations.
“Our study revealed that these people have an average risk of developing cancer as opposed to the high risk of their mutation-carrying close relatives and hence do not need to worry unnecessarily and over screen to detect cancer,” says Jenkins.
“While not a common condition, approximately 20,000 Australians have Lynch syndrome and a very high risk of cancer. Over time, as improved screening methods become available, the findings may help doctors refine screening guidelines for breast, uterus, colon and other cancers among patients with Lynch syndrome.
“In the meantime, genetic testing will give people a clearer indication of their real risk level and clarify what they could or should not do to reduce their risks of cancer.”
People who think they might be at increased risk for cancer due to family history should consider genetic testing and seek medical advice so that any cancers can be detected and treated as early as possible.
More news from the University of Melbourne: http://newsroom.melbourne.edu/