Prognosis                                                                                                            

“How long do I have?”
Prognostication is always difficult, because it involves applying population-based statistical information to an individual situation, and integrating it with any other significant comorbidities.

There is evidence that medical practitioners are generally poor prognosticators, and tend to over state survival. The length of the doctor-patient relationship also affects doctors’ ability to objectively assess prognosis. GPs and other doctors who have had a long relationship with a patient tend to over state prognosis. This may not be helpful.

Why patients and families need to know
For patients and families, having an idea of where they are up to and what to expect allows them to make reality based plans:

• The difference between a prognosis of days to weeks, versus a few months, is enormous. It may completely change a person’s priorities – where they want to be, with whom, and how to spend their remaining time
• Patients’ attitudes to ongoing treatment and interventions often shift as prognosis shortens.

Decisions about site of care may be affected by prognosis:

• Caregivers are sometimes able to provide intense care for a short burst, but unable to sustain the same care for months, so knowing that time is short affects options for care;
• Hospices cannot provide long-term care; families may need to think about residential aged care if the prognosis is months and care needs are otherwise straightforward.

Performance state as a prognostic tool

• Performance state provides an objective way of tracking prognosis in cancer. The most common measures used in oncology are:
  • The Karnofsky scale
  • The ECOG scale. from the Centre of Advanced Palliative Care website 
• A Karnofsky score of less than 40 or an ECOG score of greater than 3 correlates to a median survival of around 3 months. NB: these predictions are validated in cancer, but not in non-malignant disease other than AIDS.
• Performance state is taken into account by most oncologists when making treatment and management decisions. In general, patients with a poor performance state benefit less from most treatments (the most important possible exception being highly chemosensitive or radiosensitive diseases such as small cell lung cancer and high grade lymphoma)
• The rate of change in performance status is a useful global index of deterioration.

These issues are summarised in the EPERC Fast Fact on prognosis in advanced cancer

A modified Karnofsky scale for use in palliative care is available from the Centre of Advanced Palliative Care website.

This page was created on 26 March 2007 and is due for review in March 2009