Colorectal cancer is the second leading cause of cancer deaths in the United States. According to the American Cancer Society, an estimated 150,000 people in the U.S. are diagnosed with colorectal cancer and about 56,000 people die from it every year. Yet, the disease can be cured if detected early enough.
Like most other forms of cancer, the risk of colorectal cancer grows with increasing age. Colonoscopy, which can identify early stages of the cancer, is recommended for everyone over the age of 50.
Most cases of colorectal cancer cannot be predicted, but a few cases are known to result from inherited genetic abnormalities. The most common genetic cause of colorectal cancer - comprising about 5 percent of all colorectal cancers - is the Lynch syndrome. The Lynch syndrome is also associated with other cancers, especially ovarian and uterine cancers.
The only way to detect the genetic abnormalities that cause the Lynch syndrome has been through expensive laboratory tests. Screening methods that reliably predict the likelihood of Lynch syndrome are sorely needed.
There is hope for such screening tools. Just this month, publications from Johns Hopkins and Harvard described two different screening methods that more accurately predict the syndrome than previous methods. Each screening tool relies on a detailed history of cancers in the individuals being screened and their family members.
Both tests are designed to be used by professionals. The Hopkins software, known as MMRpro, can be opened online here; the Harvard program can be reached online here The current version of the Hopkins program only considers the prediction of endometrial cancer, the most common type of Lynch syndrome cancer other than colorectal cancer.
About half of the 600,000 people in the U.S. who carry the mutations causing the Lynch syndrome will be diagnosed with colorectal cancer by the age of 70. For them, colonoscopy is recommended at one- to two-year intervals beginning in the early- to mid-20s. In addition, about half of the women with the Lynch syndrome will develop cancer of the uterus.
