More Detailed Information on Key Tier 1 Applications - Lynch Syndrome
LS is a hereditary disorder associated with an increased predisposition to colorectal, endometrial, ovarian and other cancers due to inherited mutations in a class of genes known as mismatch repair (MMR) genes. LS is also referred to as hereditary nonpolyposis colorectal cancer (HNPCC). People with LS have a greatly increased chance of developing colorectal cancer (CRC), often at less than 50 years of age, and women with LS are also at greater risk of developing endometrial and ovarian cancers. If an individual is found to have LS, his or her relatives can be tested to determine if they also carry the mutation. Relatives found to have LS can significantly lower their chances of developing or dying from cancer by having earlier and more frequent colonoscopies and availing themselves of other preventive strategies (beyond the scope of this toolkit).
Facts About LS
- LS has an autosomal dominant inheritance pattern (only one copy of the mutation is needed to manifest the disease; first-degree relatives (parents, children, siblings) of an affected person have a 50% risk to inherit the mutation); other relatives (e.g., grandparents, aunts, uncles, cousins, nieces and nephews) are also at increased risk.
- Among people with LS, lifetime risk for CRC ranges from approximately 20-80%, depending upon the mutation involved, the sex of the affected individual, and the population studied;
- Mean age of onset of CRC in those with LS is approximately 45 years; and
- People with LS have an increased risk of other malignancies including those of the endometrium, ovary, urinary tract, gastric tract, small bowel, pancreas, and skin (sebaceous).
The Evaluation of Genomic Applications in Practice and Prevention (EGAPP™) Independent Working Group found sufficient evidence to recommend offering genetic testing for LS to individuals with newly diagnosed CRC to reduce morbidity and mortality in relatives. The complete EGAPP recommendation statement [PDF 219.30 KB] on genetic testing was formulated in 2009.
The LS Tier I application involves screening of every newly diagnosed colorectal tumor in a patient and then the subsequent offer of genetic testing to people whose tumors are positive. Those diagnosed with LS after CRC can be offered preventive options to reduce morbidity and mortality from other LS-associated cancers, and their first-degree relatives can be offered genetic testing prior to manifesting cancer so that they can avail themselves of enhanced CRC screening and other preventive options.
Approximately 3% of people who develop CRC have LS, accounting for about 4,200 cases each year in the U.S. We have estimated, by state, the number of persons with LS who could be identified by screening all persons with newly diagnosed invasive CRC. These estimates are based on the numbers of incident CRC cases reported by state cancer registries in 2009.
Public health can work with and encourage medical providers and payers to facilitate the development of programs to identify individuals who should be offered genetic testing for LS. Based on accomplishments in Michigan, Oregon and other states, public health departments can now consider one or more of the four major approaches described below under “Phase 1 Approaches.”
Phase 1 approaches include: (1) “bi-directional” cancer registry reporting for case finding or other purposes; (2) providing information to policy makers that will allow them to make more evidence-based decisions about coverage and other issues; (3) developing and tracking surveillance indicators to follow progress in achieving widespread implementation of the Tier 1 recommendation and /or the Healthy People 2020 objectives; and (4) designing and implementing educational outreach programs targeting public and health professional groups with an interest in or need to know about the LS Tier 1 application. These efforts, called “Phase 1” approaches, take advantage of a few states having implemented some of these actions. States which have already successfully implemented one or more of the Phase 1 approaches may be ready for more advanced “Phase 2” projects such as cascade screening to identify at-risk family members of index cases. While the challenges and opportunities within each state differ, success in any of these efforts requires establishing strong partnerships among public health and providers and payers within each state’s boundaries.