The above is the title of a story published by the AP. Why are there more cancer survivors? Here is the explanation offered by the story:
More people are surviving cancer, in part, because of earlier detection and better treatment, they (health officials at the Centers for Disease Control) said. In 2007, there were about 11.7 million Americans with a history of cancer, the Centers for Disease Control and Prevention said.
Forty years ago, the number of cancers survivors was about 3 million. That increased to 10 million in 2001 and to 11.4 million in 2006. Healthy eating, less smoking and other preventive steps may also be playing a role in the increase, health officials said.
Here are the most recent (2011) cancer mortality data published by the American Cancer society.
How does one reconcile the slight decline in cancer mortality with an almost 400% increase in the number of cancer survivors? This question does not seem to have occurred to the lay press. It has to clinical epidemiologists, but apparently not at the CDC. One would expect a decline in cancer mortality similar to that seen in heart disease if the increase in the number of cancer survivors was the result of better treatment that prolonged life. Instead this increase in survival is mostly due to over diagnosis.
If we diagnose a patient with cancer and this cancer will never kill him he becomes a long term survivor. He tells everyone he’s a cancer survivor, all are impressed with the march of medicine, and the CDC makes a press announcement. And what have we accomplished? Nothing other than expense.
What has happened is that “cancers” never destined to be lethal are being diagnosed and treated. This over diagnosis results in an increase in cancer survivors that provides the public with reassurance that we are making great progress against the disease, but this good feeling is mostly meaningless. Worse it exacts a great psychic and fiscal price.
The problem of over diagnosis is best exemplified by that for breast and prostate cancer. A recent paper in the Journal of the American Medical Society discussed this problem. Not only is this problem costly it is confusing. The public doesn’t understand it and announcements like the one above don’t increase comprehension. The CDC owes the public a better explanation than they have so far provided. The press as usual understands less about medicine than they do about nuclear physics. This is an important issue that is not that hard to understand.