When someone hears the diagnosis “cancer” the next word they think might be “terminal!” Then they’ll want to know, “how long do I have?” and they’ll sooner or later find themselves staring at a survival graph for their type of cancer.
This graph plots a survival curve on an x-y axis showing the number of patients and the amount of time they live. A survival curve CANNOT BE REDUCED TO A SINGLE NUMBER such as the “median” survival or the “overall” survival rate (OS = five years), but this is exactly what everyone looks for.
This rush to data can do more harm than good. Consider the experience of the noted biologist Stephen Jay Gould, who was diagnosed with a rare and serious abdominal mesothelioma in 1982. After surgery, he went in search of his own survival graph.
“As soon as I could walk, I made a beeline for Harvard’s Countway medical library and punched mesothelioma into the computer’s bibliographic search program . . . The literature couldn’t have been more brutally clear: mesothelioma is incurable, with a median mortality of only eight months after discovery.
“What does ‘median mortality of eight months’ signify in our vernacular? I suspect that most people, without training in statistics, would read such a statement as “I will probably be dead in eight months” – the very conclusion that must be avoided, since it isn’t so, and since attitude matters so much (emphasis mine).”
Gould used his knowledge as a tool in his successful fight against cancer. He lived for another 20 years, beating the eight-month death sentence 30 times over. He shares his insights on statistics in the article, The Median Isn’t the Message, which has been an encouragement to me and countless others. Check it out.
“Statistics are information, not condemnation.”
– David Servan Schreiber