A study of families with Lynch Syndrome has expanded the list of cancers related to the condition: carriers of a Lynch Syndrome gene mutation also appear to have an increased risk of breast cancer and pancreatic cancer. These results were published in the Journal of Clinical Oncology.
Lynch Syndrome, also known as hereditary nonpolyposis colorectal cancer (HNPCC), results from inherited mutations in genes involved in DNA mismatch repair. These mutations greatly increase the risk of developing colorectal cancer. In individuals with Lynch Syndrome, the average age at diagnosis of colorectal cancer is about 44 years, compared with 64 years in the general population. Overall, roughly 3% to 5% of all colorectal cancers are thought to result from Lynch Syndrome. Several other types of cancer are also known to be more common in people with Lynch Syndrome, including cancers of the endometrium (the lining of the uterus), ovary, small intestine, ureter, and renal pelvis.
To further explore cancer risk in families with Lynch Syndrome, researchers conducted a study among 446 people with a Lynch Syndrome gene mutation, and 1,029 family members who did not carry a gene mutation.
Study subjects were followed for a median of five years.
- Compared with the general population, people with a Lynch Syndrome gene mutation were 20 times more likely to develop colorectal cancer, 31 times more likely to develop endometrial cancer, 19 times more likely to develop ovarian cancer, 11 times more likely to develop kidney cancer, 11 times more likely to develop pancreatic cancer, 10 times more likely to develop stomach cancer, 10 times more likely to develop bladder cancer, and 4 times more likely to develop female breast cancer.
- Family members without the gene mutation did not have an increased risk of cancer (cancer risk was similar to that of the general population).
This study confirms that people with Lynch Syndrome have an increased risk of several types of cancer, including some (breast and pancreatic cancer) that were not previously known to be linked with Lynch Syndrome.
People who come from a family with Lynch Syndrome but who do not carry the gene mutation themselves do not appear to be at increased risk of cancer.
Reference: Win AK, Young JP, Lindor NM et al. Colorectal and other cancer risks for carriers and noncarriers from families with a DNA mismatch repair gene mutation: a prospective cohort study. Journal of Clinical Oncology. Early online publication February 13, 2012.
Posted February 20, 2012