When someone has incurable cancer it is very natural that their relatives want to know how long they might live for (even if the patient themselves does not want to know) so that they can plan and start to come to terms with a distressing situation.

Unfortunately it is usually difficult, even for the most experienced cancer specialist, to give an accurate answer. This is because every patient is a unique individual and will be affected differently by their illness. Even two people of the same age, with the same type of cancer, which has spread to the same extent, can have very different survival times. This can happen because many other things influence survival including general fitness, will power, the response to treatment and the development (or avoidance) of unexpected complications.

Despite all this, if the doctor knows the type of cancer and how far it has spread then they will be able to offer 'average' figures for life expectancy. But, very importantly, these are only averages. This means that some people will live a little longer, and a few will live a lot longer, than predicted, whilst others will survive a shorter time.

So, in many ways, even an expert opinion of life expectancy for any individual patient is little more than informed guess.

Sometimes, however, even if doctors explain the uncertainties, patients and their relatives will still put great faith in the time they have been given. This can then lead to problems if things go down hill more quickly (and sometimes there are even difficulties if people live much longer than expected).

Because of this uncertainty some doctors are reluctant to offer survival times to their patients (or to relatives). Most specialists, however, will be prepared to discuss the issue, realising that people do need some idea of time scales in order to plan their lives and cope with things. But their advice is still only a guide to what might happen and not a precise forecast of what will happen.