The intriguing approach medical doctors calculate how lengthy sufferers have left to dwell – and why they usually get it mistaken…as MPs vote FOR assisted dying

MPs today took a critical step in making assisted dying a reality in England. 

The House of Commons voted in favour of the Terminally Ill Adults (End of Life) Bill which, if enacted into law, will give patients with less than six months to live the right to seek euthanasia from a medical team.

While passed, the bill still needs to go through various amendments and more votes in both the Commons and the Lords, and even if this goes smoothly it could be years before it actually comes into practice.

Debate about the controversial bill continues, including specific concerns on how accurately medics assess how long the terminally ill have to live.

Experts have told MailOnline that estimating survival isn’t an exact science. In fact, some have compared the reliability of a prognosis to that of weather forecasts.

Generally speaking, the closer a patient is to death the more accurate medics’ predictions become. 

This is because certain biological signals, such as a patient’s blood pressure, appetite and lucidity as well as heavy doses of drugs like painkillers can give medics a decent idea of if they have days or even mere hours left. 

But when it comes to longer periods, the situation can become more complicated and therefore uncertain. 

Estimates vary by study. Some suggest medics get it broadly right 50 per cent of the time, others suggest it’s as little as a third of the time.

Professor Karol Sikora, a retired oncologist and former director of the World Health Organisation cancer programme, told this website the estimates medics give when patients ask how long they have left are based on population averages from other patients.

These calculations take into account the specific disease a patient has, their age and how serious a condition is.

This means an older person with multiple tumours will most likely die sooner than a younger one even at the same stage of cancer.

One important factor to remember is these estimates are based on averages, which means exceptions apply on both ends of the scale, some will die sooner than the estimate and others will defy the odds and persist for far longer.

Professor Sikora added the reliability of these estimates can naturally vary depending on the how common or rare the condition is. 

‘Of course you can get it wrong,’ Professor Sikora said. 

‘It’s a total inexact science.’

Other experts agree. Professor Paddy Stone, former head of the Marie Curie palliative care research department at University College London, said there was no estimation method reliable enough to act as a safeguard for assisted dying.

‘My research demonstrates that there is no reliable way to identify patients with less than six or twelve months to live…at least, no method that would be reliable enough to act as any sort of ‘safeguard’ for the proposed assisted dying legislation,’ he told the Financial Times. 

Professor Irene Higginson, an expert in palliative care at King’s College London, added: ‘All the studies from this country and others show that estimating six months left to live is extremely difficult and not that accurate.’

‘The science isn’t that well developed and I’m not sure it could be, because individuals vary so much’.

Experts cite studies like one in 2023 on almost 100,000 patients that show medics were right nearly three out of four times on estimating if patient would die within a fortnight.

They were even more accurate, right four out of five times, when it came to if a patient would live more than year.

But the middle period, if a patient had ‘weeks’ or ‘months’ left was far trickier, medics only got this right a third of the time. 

Another estimate, calculated by The Telegraph, found that on 7,000 occasions medics were right on predicting if a patient would survive six months just less than half the time.

Uncertainty on estimates raises concerns that patients who might otherwise live for longer could die earlier if they opt for an assisted death.

Commenting on the data Professor Katherine Sleeman, a palliative care expert at King’s, said ‘estimating how long someone has left to live is notoriously difficult.’

She added: ‘If a person’s estimated prognosis will be key to determining whether they are eligible for assisted dying, MPs need to carefully consider how this estimate will be made, by whom, and what the likely error rate will be.’

Professor Sikora added that another, less scientific factor, he had seen throughout his career was that some patients defy the odds with a specific goal in mind. 

‘They want to live for some specific reason for example, their daughter is getting married,’ he said. 

He recalled one patient in such circumstances who had a survival estimate of mere weeks.  

‘His daughter was getting married in two months’ time and he just wanted to go to the wedding,’ he said. 

‘He made it to the wedding and died on the following Sunday. Which was fantastic for him as it was against all odds.’