A new way of predicting how long terminally ill cancer patients have to live, has been devised by Cancer Research UK-funded research.

The new guide, being presented on Tuesday at the National Cancer Research Institute (NCRI) Cancer Conference in Liverpool, UK, is based on blood tests, white cell blood count, pulse rate and patient symptoms and can predict survival at least as well as a doctor.

Scientists said that the model differed from previous scales in that it could help to give a more accurate picture of whether patients might have only two weeks or two months left to live, independently of a doctor's estimate. The scale could help families, carers and nurses make plans with cancer patients who are close to the end of their life.

The study, funded by Cancer Research UK, looked at 18 palliative care services including hospices, hospital support teams and community service and more than 1000 patients with advanced cancer who were no longer receiving treatment.

A combination of markers like blood tests, pulse rate, weight loss, tiredness, breathlessness and white blood cell count were used to produce two versions of the scale.

Dr Paddy Stone, lead study author based at St George's University of London, said; "These scales can provide valuable information for patients, carers and health professionals. It is important to remember that these results do not provide a definitive model for predicting how long someone will live, but it will give everyone concerned a clearer idea of what it is likely to happen.

"This study provides a solid starting point for improving accuracy in survival predictions which can continue to be refined and improved."

Professor Chris Todd, another author based at the University of Manchester, said: "An instrument like this will also help us identify which patients could take part in studies aimed at improving the quality of life for people receiving end of life care. We are already looking at how to improve the prediction models and how to make them readily available to clinicians through, for example, iPhones and other mobile devices."

Scientists claim that one form of the scale, which does not require a blood test, provides a prediction of survival as good as a doctor's estimate; while another version using a blood test is better than a clinician's prognosis.

The model could also be adapted to a patient who may not be able to respond to questions about their health.

Dr Lesley Walker, director of cancer information at Cancer Research UK, said: "It can be very difficult for the families and friends of cancer patients - who are no longer being treated - to deal with the final stages of their lives. Being told you are terminally ill brings a great amount of uncertainty; any information which can help carers and families cope with this and help plan palliative treatment is extremely useful."

Source: National Cancer Research Institute