The Guardian 2 June 2015
One of the largest reviews, published in the British Medical Journal, systematically reviewed survival predictions in terminally ill patients with cancer. Eight studies were analysed in three countries over 30 years.
Overall, doctors’ predictions were correct to within one week in 25% of cases, correct to within two weeks in 43%, and correct to within four weeks in 61%. The study found that doctors tended to overestimate survival.
The very measure of a doctor lies in their predictive abilities, their grasp of the crystal ball: “How long have I got, doctor?” The Corpus Hippocratum of early Greek medicine underlined just that: “I hold that it is an excellent thing for a doctor to practise forecasting. For indeed, if he discover and declare unaided by the side of his patients their present, past and future circumstances, he will be able to inspire greater confidence that he knows about illness, and thus people will decide to put themselves in his care.”
Why is it so difficult to prognosticate?
Every patient is different, every disorder is different, every disorder within a disorder is different. People are unpredictable, their illness even more so. But there exist other subtleties that are harder to admit to.
Jules Montague is a consultant neurologist at the Royal Free London NHS Foundation Trust, and an honorary consultant neurologist at the National Hospital for Neurology and Neurosurgery, Queen Square.