Terminally ill teenager defies predictions but that doesn't mean doctors were wrong

The Court of Protection recently reviewed the case of an 18-year-old teenager with a relapsed brain tumour. In February, the court heard from medical specialists that he was expected to die within two weeks, and authorised doctors to withhold chemotherapy, neurosurgery and other invasive treatments, against the wishes of the boy’s parents.

However, three months after that ruling, the teenager is still alive. As Yogi Berra famously said: “It’s tough to make predictions, especially about the future”. So what should we make of this case? Were doctors and the court wrong?

The first point to note is that medical prediction of outcome is almost always riven by uncertainty. Clinicians don’t have a crystal ball. All we can know with absolute certainty is what has happened in the past. Doctors look back on past cases and published scientific studies. Based on that experience, it is possible to estimate what will happen to a group of patients with similar disease features. However, it is much harder to say what will happen for the single patient in front of us.

In this case, the fact that the patient has done better than predicted does not mean that the initial prediction was wrong. Imagine that a doctor estimates that there is a 99% chance that a patient will die within a short period of time. The patient returns some time later – still very much alive, and says to the doctor: “you were wrong”. But based on the doctor’s prediction, we would expect one out of 100 patients to survive for longer. Those patients have not “defied predictions” – they are exactly what was predicted.

Exceptions get the attention

Media reports often report such exceptional cases. For example, guitarist Wilko Johnson performed a farewell tour in 2013, after being diagnosed with terminal pancreatic cancer. But earlier this year he was given the all clear. And almost every week there are stories in the newspapers of miracle survivors. This can give the impression that doctors are frequently wrong in their predictions. But that does not follow either. Cases where the patient died as predicted are not newsworthy. Stories of patients dying within a short space of time don’t get reported.

There is more robust evidence about how well doctors are able to predict. A systematic review, published in the British Medical Journal in 2003, assessed how accurately doctors had predicted survival duration in terminally ill patients with cancer. That study found that predicted survival was strongly related to actual survival. However, and this is important, doctors mostly overestimated survival.

Doctors were correct to within a week in only a quarter of cases. They overestimated survival by at least four weeks in another quarter of cases. The recent report by the parliamentary and health services ombudsman highlights that many patients do not receive the end-of-life care that they need – in part because of this problem with overestimating survival.

The palliative paradox

One interesting possibility about this specific case is that the patient lived for longer than expected because he did not receive the chemotherapy that had been requested by his parents. We could call this the “palliative paradox”.

People think that making a decision to have palliative care or to go into a hospice will lead to the patient dying sooner. But the opposite is at least sometimes the case. An important study published in 2010, found that patients with advanced lung cancer who saw palliative care specialists lived 25% longer than those patients who had usual care from oncologists. Other studies have found that hospice care extended the life of patients with pancreatic cancer by three weeks, and those with heart failure, by three months. US surgeon Atul Gawande has written: “The lesson seems almost Zen: you live longer only when you stop trying to live longer”.

It is entirely appropriate that the court revisited its previous decision – given that the young man has survived for longer than expected. Patients, families and doctors make decisions together to withhold some medical treatments because they are not working, or because they seem to risk doing more harm than good. But that may change over time. In this case, the court decided that one treatment, which was previously thought to be ineffective, (flushing the young man’s extra-ventricular drain that relieves pressure on the brain) should now continue.

People sometimes think about decisions about life-prolonging treatment as a fork in the road. They see palliative care as a one-way track and worry that once they have left the main road they will never be able to return. But palliative care and life-prolonging treatments are not in conflict and they are not mutually exclusive.

Two routes in parallel.Ronald Saunders, CC BY-SA

Conventional medical treatment is more akin to a river, while palliative care is the path running alongside. Sometimes it is appropriate to climb out of the water, and to walk more slowly along the towpath. Often, once people have left it, they have no desire to return to the river. But others will find, after some time, that they are ready to plunge back in. This may be for a short dip, or for a long swim. But the palliative path will be there at the side when they need it.

Dominic Wilkinson receives funding from The Wellcome Trust, and has previously received support from the National Health and Medical Research Council (Australia).