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Genetics and Cancer Risk: More Options, More Tests, More Prevention, More Survivors

Publication: The McAllen Monitor, McAllen

Two years ago this month, in a landmark case for cancer prevention, the Supreme Court ruled that human genes cannot be patented. The decision ended a Utah company’s monopoly on a test for abnormalities in two genes (BRCA-1 and BRCA-2) that are associated with an increased risk of developing breast and ovarian cancer. Since the court decision, companies have introduced new, lower priced genetic tests.

Also, new technology called Next Generation Sequencing (NGS) has expanded the array of cancer associated genes that can be evaluated, with new test panels that can assess from four to more than 50 genes at one time. Costs range from a few hundred to several thousand dollars.

More genetic testing options offer the potential of early detection in patients with enhanced risk of developing colon, breast, uterine, ovarian and kidney cancer. Patients who know that they harbor genetic abnormalities can work with their physicians to develop risk reduction and preventative strategies, which ultimately will save lives.

But there is a potential down side to readily available, low cost testing — if patients consider test results alone, outside of a comprehensive risk evaluation. Properly determining cancer risk involves several steps.

First, the patient’s personal and family history, ideally a three generation pedigree (family tree), is examined. Then, discussion is needed to determine if testing is likely to provide meaningful information that can help in developing a medical management plan. Weighing the pros and cons of being tested and then ordering the appropriate test is only step one.

The genetic testing marketplace today is growing and changing, with more than 20 companies entering the testing arena in the past two years. Some market directly to consumers — a grave concern to those of us involved in cancer risk assessments. Companies vary in quality, experience and interpretation of testing results. Also, there are nearly a hundred different test panels on the market today. For example, one company’s “breast panel” might examine nine genes while a competitor offers an expanded 23 gene panel.

Another concern is the expansion of genetic testing to include examining rare or uncommon genes, resulting in a proliferation of difficult to interpret results. Companies are reporting “variants of unknown significance” (VUS) in approximately 35 percent of their test results. But classifying results as benign (not associated with a risk of cancer) or deleterious (known to cause an increased risk for cancer) can be inconsistent from one test provider to another.

This increased complexity adds to the essential importance of counseling in genetic risk evaluation. Some patients with negative test results may actually have significant cancer risk based upon personal or family history. Counseling and the development of a management plan after testing is more important than the test results.

The development of more testing options is a major advancement in cancer prevention. But putting test results in their proper, patient-specific context is paramount. Unlike home pregnancy tests, there’s no “pink strip indicator” simple answer to the question: Am I at high risk for getting cancer?

That’s why oncologists and genetic counselors emphasize the need to avoid either false reassurance or unwarranted worry from test results. Patients seeking a cancer risk evaluation should choose a program that: Is managed by experienced cancer risk assessment teams, maintains a prospective registry and includes pre- and post-testing counseling.

Fortunately, a number of such programs are available in Texas. Cancer risk assessment, ultimately, is not about a test kit. Rather, it is about evaluating and managing a population of individuals concerned about their personal cancer risk.

Dr. Billie J. Marek is the Medical Director for Texas Oncology in the Rio Grande Valley

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