Genetic Testing for Lynch Syndrome Helps Identify Colorectal Cancer Risk

Highlights

People with Lynch Syndrome are at high risk of developing colorectal cancer and endometrial cancer
Three out of every 100 colorectal cancer is caused by Lynch Syndrome
Genetic testing of colorectal tumors helps identify people with Lynch Syndrome

Lynch Syndrome is a genetic condition that increases the risk of colorectal cancer. A new study suggests that healthcare providers support routine testing of colorectal tumors to identify more people with Lynch Syndrome.

Is Routine Genetic Testing of Colorectal Tumors Necessary?

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‘Routine genetic testing for Lynch Syndrome for patients with colorectal cancer can improve identification of families at high risk of developing cancer.’

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A study was conducted to examine whether patients can opt out of the routine testing of colorectal tumors. The study was conducted by Dr Yvonne Bombard, Genomics and Health Services researcher in the Li Ka Shing Knowledge Institute of St. Michael's Hospital. Surgeons, genetic counselors, oncologists, primary care physicians and gastroenterologists were interviewed for their views and experiences on colorectal tumor testing, results, counseling patients with Lynch Syndrome and their families. The healthcare providers’ vision for the design and implementation of routine genetic testing were also asked.

Yvonne Bombard

Some healthcare providers suggested that patients should have the right to opt out of the routine genetic test for Lynch Syndrome. But, some said it is necessary to carry out routine genetic testing to help identify and manage patients with Lynch Syndrome and their family members who might be at risk.

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Healthcare providers who supported that patients should be allowed to opt out of the routine test pointed to the need to protect patients who test positive and may suffer distress and insurance discriminations. There is also the need to avoid unnecessary anxiety for patients who test negative. Providers also worried about the long wait for appointments with genetic counselors for patients identified with Lynch Syndrome.

Routine genetic test alone may not improve the overall care for patients with Lynch Syndrome. Creating awareness about the condition may help improve the overall care.

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"Providers emphasized that the introduction of routine testing alone would not necessarily improve care overall for Lynch Syndrome patients and their families. They felt that a comprehensive approach was needed to increase awareness of Lynch Syndrome in the wider medical community and that substantial change would need to occur to improve coordinated care, adequate resourcing for genetic services and ongoing surveillance, and provider awareness and education of Lynch Syndrome," said Dr Bombard.

"Many healthcare systems are considering implementing routine testing for Lynch Syndrome for patients with cancer to improve identification of families at high risk of developing colorectal cancer for more intensive screening. This research will help guide how these programs should be developed,” said Dr Nancy Baxter, chief of the General Surgery Department at St. Michael's and one of the paper's co-authors.

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Limitations of the Study

Only a small number of healthcare providers were interviewed for the study and patients’ views were not analyzed. Dr Bombard said that patients' views are needed to ensure that their preferences were incorporated into the design of any program.

The study is published online in the journal Genetics in Medicine.

Link Between Lynch Syndrome and Colorectal Cancer

Genes such as MLH1, MSH2, MSH6, PMS2, and EPCAM have been linked to Lynch Syndrome. A mutation in any of these genes increases the risk of many types of cancer, particularly cancers of the colon and rectum (colorectal cancer). People with Lynch Syndrome also have an increased risk of cancers of the stomach, gallbladder, brain, skin, and uterus (endometrium). Lynch Syndrome accounts for about three to five percent of colorectal cancer cases. Three out of every 100 colorectal cancer is caused by Lynch Syndrome. Early detection and treatment can reduce the incidence of colorectal cancer.

Genetic Tests for Lynch Syndrome

Genetic testing is recommended for people with a family history of Lynch Syndrome. Two genetic screening tests are performed on tumors to identify people with Lynch Syndrome.

Microsatellite instability testing (MSI)
Immunohistochemistry testing (IHC)

Reference:

Should patients be allowed to opt out of routine genetic testing of colorectal tumors? - (https://www.eurekalert.org/emb_releases/2016-10/smh-spb100416.php)

Source-Medindia