Tuesday's New York Times ran a story about the unreliability of the tests and the variation among laboratory standards that determine the potential effectiveness of new targeted cancer treatments. Linda Griffin, a physician with breast cancer, described the series of treatment decisions she made with her doctors about whether or not to take the very expensive, fairly disruptive and potentially very effective drug, Herceptin, based on a genetic test that was inconclusive and further, which produced different findings when the same material was retested. From the NYT story:
HER2 tests, for instance, can give false-positives up to 20 percent of the time, wrongly telling women they need the drug when they do not. Five percent to 10 percent of the time the tests can falsely tell a woman that she should not take the drug, when she should.
As a result of frequently observed variations like these,
HER2 testing guidelines (have been developed) by the College of American Pathology and the American Society of Clinical Oncology, dictating criteria for declaring a test positive or negative and requiring proficiency testing, among other things.
About 900 of the nation's estimated 1,500 labs agreed to follow the guidelines.
But even so, said Dr. Bloss of GlaxoSmithKline, there seemed to be approximately a 20 percent discordance between labs.
Despite all the tests and the incredibly sophisticated science behind Linda Griffith's choices, there was no right answer about which treatment to pursue. She and her doctor had to weigh the risks of 1) the cancer itself, 2) the inaccuracy of the genetic test 3) the potential effectiveness of Herceptin to treat her cancer and 4) the intrusive side effects. This was not a one-shot choice, but rather a series of excruciating decisions made together under conditions of great uncertainty.
Making such decisions about high stakes risky treatments requires a strong, flexible relationship with a provider you trust that allows you to thoughtfully blend your preferences and needs and tolerance for risk with your provider's own expertise, experience and tolerance for risk.
Similar situations will become more typical for people with a variety of serious diagnoses as new first-line treatments become available with little evidence to guide their use. Personalized medicine targeting special medications that match an individual's genetic make-up is increasingly seen as a potential solution to many intractable diseases.
That said, many treatments currently in use for cancer and MS and some heart conditions already require that we weigh risk against risk, uncertainty against uncertainty, even without the added genetic information. Sometimes we don't ever realize we have this option we just do what our doctor suggests. Or we locate a decision support guide that arrays various risks for us and we try to personalize those numbers to our lives. Or we struggle to sort through the options with our physician in the brief time available to us.
Much will have to change on our end and on our providers end if medical advances are to make a difference to us. Increasingly, we are going to have to pay attention educate ourselves be ready to talk turkey about complicated and frightening options. And our providers are going to have to bring us along, make it possible for us to understand and deliberate with them and with our loved ones and ultimately to make decisions that are right for us.
Linda Griffin repeated her genetic test; she read the background literature in preparation for her meeting with her doctor.
In the end, the studies, along with Dr. Winer's clinical perspective, did not convince her that the drug would help. The risk of serious heart damage and other side effects was scary. And, she said, she cannot ignore the drug's price, even though her insurer would pay.
I am very comfortable with my decision, she said.