Pamela A. Popper, Ph.D., N.D.
Wellness Forum Health
In the history of medicine, we see several recurring themes, one of which is the tendency to become enthralled with new tests, drugs or procedures before they have been proven to be safe or effective. The idea is that new is always better, and that more information always improves health outcomes.
This certainly is the case with genetic testing, particularly with genetic testing for breast cancer. The promise of genetic testing was that it would lead to more tailored treatments based on a patient’s genetic makeup, which sounds like a great idea.
Two types of genetic tests are becoming standard practice for breast cancer patients. One test is to see if these patients have inherited mutations that predispose them to develop cancer, and the other is to test tumor cells looking for mutations that caused the tumor’s growth. But as of now, it is not clear that inherited mutations are the cause of cancer (many women with mutations do not develop cancer, while many without mutations do), and there are usually no drugs that target mutations identified in tumor cells. In other words, testing generates lots of information, but no real improvement in treatment approaches. This can be frightening to women who are given this information since there is no plan of action available for addressing it. Eric Winer, director of breast oncology at the Dana-Farber Cancer Institute says that “…our ability to sequence genes has gotten ahead of our ability to know what it means.”
Doctors tend to become fascinated with new things, which has been the case with genetic testing. The problem is that since there is no clear advantage to having this information – no objective guidelines for actions that should be taken – doctors sometimes misinterpret test results and/or offer opinions and advice not supported by evidence. Women are often told that they should have prophylactic mastectomy or oophorectomy, or that more aggressive drug treatment for their cancer is warranted. Many mutations are labeled as “a variation of unknown significance,” which is another way of saying “we have no idea what this means.” So why are we spending billions of dollars on discovering things that do not improve outcomes?
As with all other diagnostic tests, the more tests run, the more likely an abnormality will be identified. There is about a 5% chance of finding “a variation of unknown significance” for each gene tested, so the more genes tested the more likely a mutation will be found. More genes are being tested in accordance with the “more is always better” philosophy.
To add additional complication, most women with breast cancer have several gene mutations, not just one. And at this time, it is impossible to identify which ones matter. Billions of dollars have been spent trying to figure this out, and with the exception of Gleevec, there have been no successful treatments developed for cancer based on genetic mutations. According to Dr. Thomas Seyfried, author of Cancer as a Metabolic Disease, almost 700 drugs developed for the purpose of treating gene mutations have failed in clinical trials. This may be why Dr. Norman Sharpless, director of the Lineberger Comprehensive Cancer Center in North Carolina says that only 1 in 1000 women with advanced breast cancer will benefit from treatment with either approved or experimental drugs based on their gene mutations.
Fortunately, there is growing recognition that gene testing is, at least for now, mostly useless. Much of the information for this article came from a New York Times piece, and the Times has a large subscriber base. This is good, and it may result in more patients saying “no” to the recommendation for genetic testing.
But I think we are debating the wrong issue. Dr. Thomas Seyfried, referenced earlier, is a geneticist who says that genetic mutations are not the cause of cancer, but rather that gene mutations follow after a cell turns cancerous. He presents a lot of evidence for this theory in his book, and says that this may be why attempts to develop treatments based on gene mutations have failed.
The problem is that research and medicine have become fully invested in the gene theory of cancer, researchers who pursue this theory are more likely to qualify for funding, and the train has left the station in terms of doctors – in spite of revealing nothing constructive, a significant number of oncologists and medical centers aggressively promote gene testing. To avoid harm, cancer patients have to just say “no” to genetic testing.
Gina Kolata “When Gene Tests for Breast Cancer Reveal Grim Data but No Guidance.”
New York Times March 11 2016