Genetic testing isn't ready

In September, The Pharmacogenetics Journal had an interesting, and brief, commentary on personalized medicine - specifically the current state of genetic testing to determine disease risk. Their point? That the science isn't in agreement with the commercial status.

"The goal of personalized medicine is to utilize a person's genetic makeup for appropriate disease diagnosis and treatment...many onlookers with business acumen...seek commercial gains by offering to decipher the genome of individuals for a fee. The fast rate at which these startup companies have become popular gives the public the impression that the science is moving at equal pace. However, that is not true. These personalized medicine companies say they are merely providing 'information' about an individual's health/disease risk. However...there is not yet scientific consensus on the risk factors for more common complex diseases... Yet for a $1000 or more, one can submit a DNA sample to be sequenced by these companies and a report is sent back with a disease risk assessment."

Genetic predisposition to disease is an extremely complex bag and is only clear for very few monogenic diseases - the more genes involved in a disease process the less clear their roles. Commercial companies may say they can tell you your disease risk for, for example, hypertension or heart disease, but they really can't. That information is based on a limited amount of knowledge about a limited number of diseases.

This topic came up quite often when I was doing my dissertation work. My studies involved disease risk assessment based on gene mutations in hypertension- essentially the very thing the genetic testing looks for. The idea was that we had to be careful how to portray the findings because what was true for the majority of a population (i.e. significant risk factor) is not true for every person on an individual level. Risk is simply that, risk. Having a genetic predisposition does not mean one will get the disease, just as not predisposed will not mean a person will not get the disease. Genetics is only one factor in the development of these diseases, with environment (and we're finding out epigenetics) playing a large and significant role in their etiology and severity.

Genetic screening on the limited information we currently have is not valid for polygenic diseases like hypertension, heart disease, cancer, and a number of other complicated disorders people worry about*.

*Note: There are sure things like duplicated or missing chromosomes (chromosome abnormalities, such as fetal screening for Down's Syndrome) or monogenic diseases (classic Mendelian dominant and recessive genetics). These are currently screened in fetal or newborn populations if they require life-long medical intervention or considerations, or they result in miscarriages.

Massachusetts is an example to follow

As of July 1, drug company gifts to doctors are banned in Massachusetts. The legislation also limits free meals and requires that companies report any payment for consulting or speaker fees that amount to more than $50. This law affects all companies that do business in Massachusetts, meaning that it will cover doctors all over the country who interact with the many biotech and pharma companies around Boston. This is a step forward for consumers and patients to be treated without the psychological imprinting of doctors towards certain drugs or devices and for an open and transparent indication of what companies foot the bill for a doctors' speaking engagements, preventing "educational programs" from being disguised marketing programs. They will likely still be such, but it will now be blatant. Firms say that this will make Massachusetts unfriendly towards their companies, but if other states follow, the companies will have no choice but to be open about their practices. This is a step forward for patients, and companies have to realize that life is more important than sales. Read more here.

The dangers of some ovarian cancer screening methods

It's always a good thing when there is a way to avoid a late-stage diagnosis of any disease, and ovarian cancer is no exception. But before you push your doctor for the procedure, read The Skeptical OB's synopsis of a new study explaining the risks. The screening injures 2-20 times as many women as the disease, depending on the detection method, with only twice as many dealing with cancer than dealing with adverse side effects of the surgical screening outcome, and the number of true diagnoses is rather small (0.05% of all women screened) to begin with.

"The study screened more than 100,000 postmenopausal women for ovarian cancer. Half had ultrasound and CA125 tests (multimodal screening); the other half had ultrasound alone. Ovarian cancer was detected in 87 women, 42 in the multimodal group and 45 in the ultrasound alone group... in order to make those diagnoses, 942 women had surgery. In other words, 855 women had major abdominal surgery for no reason. Of those, 24 experienced major complications including perforation of an organ (requiring surgery for repair), hemorrhage, deep vein thrombosis, and pulmonary embolus."

"Screening hurt far more women than were helped. For every woman who was diagnosed with ovarian cancer, 9 more had surgery that they didn’t need, and 2.8% of women who had unnecessary surgery sustained serious, life threatening surgical complications."

What does this mean? It means the medical community has more work to do to figure out how to detect ovarian cancer at an early stage. However, if you do get screened for ovarian cancer, get both an ultrasound and the CA125 blood test, as multimodal screening decreases the risk of unneeded abdominal surgery and both tests are relatively noninvasive.