Lessons from history #7: medically induced thyroid cancers

In the 1940s to 1960s, children with an upper respiratory illness were often thought to have an enlarged thymus gland (in the neck), and were given some radiation therapy to settle it down. The thymus shrank after being irradiated and the kids generally got better, so the practice continued. It didn't matter that this was not a real disease, or that the treatment was not appropriate, or that the kids would have improved anyway; doctors did something and the patients got better. That, and some cockamamie biological explanation, was all the doctors needed. Well, that and some insurance to cover the medical costs of the kids who got cancer as a result of the radiation.

Is medical practice running ahead of the evidence?

Recently, while debating a respected colleague regarding a shift in practice towards treatment X, despite a lack of evidence showing its superiority, my colleague said: “But we know that practice always runs ahead of the evidence”. He was implying that the evidence would one day catch up and justify the practice. I wondered if medical practice really was running ahead of the evidence, or whether it was running away from it.

When clinical practice does run away from the evidence, we tend to spend our time gathering evidence to support the current practice, instead of using an objective evaluation of the current evidence to inform future practice. This is known as putting the cart before the horse. It is also known as Confirmation Bias.