Performance Status in Oncology
In oncology (cancer) and other medical fields, performance status is an attempt to quantify cancer patients' general well-being. This measure is used to determine whether they can receive chemotherapy, whether dose adjustment is necessary, and as a measure for the required intensity of palliative care. It is also used in oncological randomized controlled trials as a measure of quality of life.
Scoring systems
There are various scoring systems. The most generally used are the Karnofsky score and the Zubrod score, the latter being used in publications by the WHO. For children, the Lansky score is used.
Parallel scoring systems include the Global Assessment of Functioning (GAF) score, which has been incorporated as the fifth axis of the Diagnostic and Statistical Manual (DSM) of psychiatry.
Karnofsky scoring
The Karnofsky score runs from 100 to 0, where 100 is "perfect" health and 0 is death. Although the score has been described with intervals of 10, a practitioner may choose decimals if he or she feels a patient's situation holds somewhere between two marks. It is named after Dr. David A. Karnofsky, who described the scale with Dr. Joseph H. Burchenal in 1949.
100% - normal, no complaints, no signs of disease
90% - capable of normal activity, few symptoms or signs of disease
80% - normal activity with some difficulty, some symptoms or signs
70% - caring for self, not capable of normal activity or work
60% - requiring some help, can take care of most personal requirements
50% - requires help often, requires frequent medical care
40% - disabled, requires special care and help
30% - severely disabled, hospital admission indicated but no risk of death
20% - very ill, urgently requiring admission, requires supportive measures or treatment
10% - moribund, rapidly progressive fatal disease processes
0% - death.
ECOG/WHO/Zubrod score
The ECOG score (published by Oken et al. in 1982), also called the WHO or Zubrod score (after C. Gordon Zubrod), runs from 0 to 5, with 0 denoting perfect health and 5 death:
0 - Asymptomatic (Fully active, able to carry on all pre-disease activities without restriction)
1 - Symptomatic but completely ambulatory (Restricted in physically strenuous activity but ambulatory and able to carry out work of a light or sedentary nature. For example, light housework, office work)
2 - Symptomatic, <50% in bed during the day (Ambulatory and capable of all self care but unable to carry out any work activities. Up and about more than 50% of waking hours)
3 - Symptomatic, >50% in bed, but not bedbound (Capable of only limited self-care, confined to bed or chair 50% or more of waking hours)
4 - Bedbound (Completely disabled. Cannot carry on any self-care. Totally confined to bed or chair)
5 - Death
Lansky score
Children, who might have more trouble expressing their experienced quality of life, require a somewhat more observational scoring system suggested and validated by Lansky et al. in 1987:
100 - fully active, normal
90 - minor restrictions in strenuous physical activity
80 - active, but tired more quickly
70 - greater restriction of play and less time spent in play activity
60 - up and around, but active play minimal; keeps busy by being involved in quieter activities
50 - lying around much of the day, but gets dressed; no active playing participates in all quiet play and activities
40 - mainly in bed; participates in quiet activities
30 - bedbound; needing assistance even for quiet play
20 - sleeping often; play entirely limited to very passive activities
10 - doesn't play; does not get out of bed
0 - unresponsive
Comparison
A comparison between the Zubrod and Karnofsky scales has been validated in a large sample of patients:
Zubrod 0 equals Karnofsky 100; 90-100
Zubrod 1 equals Karnofsky 80-90; 70-80
Zubrod 2 equals Karnofsky 60-70; 50-60
Zubrod 3 equals Karnofsky 40-50; 30-40
Zubrod 4 equals Karnofsky 20-30; 10-20