Is Your Doctor Keeping This
Life-Saving DNA Test From You?
November 21st, 2012 by Holly Cornish
Scientists have said for years that DNA tests will change the face of medicine. And these days, genetic testing is cheaper and more common than ever. But doctor ignorance and the profit motive continue to rank higher than patient health — even though genetic tests could save you and your family members from cancer.
That’s why I’m writing you today. I want to make sure you know about the DNA screening that provides early detection of colon cancer. Sadly, you can’t count on your doctor to tell you about it.
Continued below. . .
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Ever heard of Lynch syndrome?
Right behind lung cancer, colon cancer is the second most deadly cancer in the U.S. But here’s something you may not know: your genes can predispose you to get colon cancer.
Geneticists call the disorder “Lynch syndrome,” after Henry T. Lynch. It was fifty years ago when Lynch, then a young medical resident, started tracking families with a high colon cancer incidence.
During the mid-1990’s, geneticists confirmed Lynch’s initial findings. Research showed as many as three percent of all colon cancer cases are the result of genetics. Alaska Natives in particular are twice as likely to die from colon cancer as most other people, and Lynch syndrome is at the heart of it.
Lynch syndrome speeds up tumor growth. It’s seen in families with a high incidence of colon cancer, ovarian cancer, and endometrial cancer. So if one family member is diagnosed with one of those cancers, it could be a lifesaving measure for that person to be screened for Lynch syndrome.
Once a patient tests positive for Lynch syndrome, it’s a clue to other family members to either get screened or take preventive measures. A hysterectomy is one way to prevent tumor growth for those at risk. So, once they’ve had children, women prone to Lynch syndrome may choose to have their ovaries and uterus removed in order to prevent endometrial or ovarian cancer. Lynch syndrome patients are also instructed to have annual colonoscopies, since polyps in the colon are more likely to turn deadly for them, and quickly.
Credit for developing the DNA screening test goes to the Mayo Clinic’s Dr. Ahlquist. The test is extremely accurate, finding at least 85 percent of colon cancers and over 50 percent of pre-cancerous polyps. It measures changes in DNA that are shed from the surface of a cancerous or pre-cancerous tumor into the stool. Those changes act like a cancer signature.
Colon cancer revolution
Plenty of folks think genetic testing will bring us a new era of cancer treatment. It’s certainly becoming more common, and cheaper.
The test for Lynch syndrome can cost as little as $300. But of the 800,000 people likely to be afflicted, only 50,000 have been diagnosed. As Dr. Lynch puts it (at 84, he now directs the Hereditary Cancer Center at the Creighton University School of Medicine in Omaha), “There are people dying needlessly.”
According to the American Cancer Society, colorectal cancer killed 50,000 people last year. And this is a cancer with no symptoms in the early stages.
In 2009, the U.S. Centers for Disease Control and Prevention issued a recommendation that anyone diagnosed with colon cancer get tested for Lynch syndrome. They also recommended testing for relatives of those patients as a preventive measure.
Despite that, less than half of all hospitals with cancer programs offer routine screening for the condition. A study in the Journal of Clinical Oncology showed only 5 percent of patients diagnosed with colon cancer were also given genetic tests for Lynch syndrome.
Dr. Ahlquist, original developer of the Lynch syndrome test, is now working with both the Mayo Clinic and a company called Exact Science to develop a commercial test. Ahlquist predicts a revolution in colon cancer screening, much like the effect the Pap smear had for cervical cancer fifty years ago.
Importantly, both the Mayo Clinic and Exact Sciences are likely to profit from development of this commercial test … which means they’ll have a motive to get the word out to doctors who could make a difference.
The doctor-education problem
So why haven’t doctors been taking advantage of this powerful test? Too often, the problem lies with overworked primary care docs who have little background in genetics. They don’t recognize the warning signs across family health histories. Many doctors don’t even know about Lynch syndrome. So they don’t send their at-risk patients to a genetics counselor.
Even if they did know about it, busy physicians don’t have a lot of time to invest in what it takes to get a genetic test recommended. Part of the work involves figuring out whether other family members had related cancers, collecting tissue samples, and setting up the genetic test.
The doctors who treat colon tumors and related cancers tend to focus on treatment first, not family history or genetics.
Then there’s the profit problem. Tests for the BRCA breast cancer genes bring in a lot of money. Tests for colon cancer? Not so much. Maybe that’s why doctors refer twice as many patients for inherited breast cancer genes as they do for hereditary colon cancer, despite the fact both diseases are equally common. Colon cancer just lacks the awareness that breast cancer has, thanks in part to well-known charities like Susan G. Komen for the Cure.
It’s also an establishment problem. The medical system just doesn’t know how to efficiently use genetic knowledge as preventative treatment.
Not a cure, but still pretty good
Knowledge about Lynch syndrome gives doctors and hospitals a terrific opportunity to educate patients and prevent many cases of colon cancer. But patients continue to slip through the cracks. Sometimes multiple family members are diagnosed with colon cancer or related cancers, yet nobody links the disease to Lynch syndrome.
Like too many of the things we write about here, it all comes back to money. No single company has rights to gene testing for Lynch syndrome, so few bother to market it. Several companies offer the test, but because none of them command enough market share to invest in both doctor and patient education, nobody does it.
Also, remember — we’re talking about DNA here. There’s still a lot of apprehension associated with DNA tests, and people from families known to carry Lynch syndrome sometimes skip the test because they’re afraid of the stigma, or even possible discrimination from insurers and employers (yes, in spite of the law).
For now, we have to wait for FDA approval of the Mayo Clinic/Exact Sciences test, which probably won’t happen till early next year. DNA tests are also in the works right now for several other cancers, including brain cancer, lung cancer, and pancreatic cancer. Experts say these tests have the potential to transform the way we diagnose and treat cancer.
So it’s not a cure, but at least DNA screening means early detection, and early detection means a much better survival rate.
Lee Euler, Publisher