In medicine (oncology and other fields), performance status is an attempt to quantify cancer patients' general well-being and activities of daily life. 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.
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.
The Karnofsky score runs from 100 to 0, where 100 is "perfect" health and 0 is death. Although practitioners occasionally assign performance scores in between standard intervals of 10, there is no substantiated rationale for this and prognostication is not improved. This scoring system is named after Dr David A. Karnofsky, who described the scale with Dr Joseph H. Burchenal in 1949. The primary purpose of its development was to allow physicians to evaluate a patient's ability to survive chemotherapy for cancer.
- 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.
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: Its advantage over the Karnofsky scale lies in its simplicity.
- 0 – Asymptomatic (Fully active, able to carry on all predisease 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
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 gets 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
A translation between the Zubrod and Karnofsky scales that works especially well for healthy patients has been validated in a large sample of lung cancer patients:
- Zubrod 0-1 equals Karnofsky 80-100
- Zubrod 2 equals Karnofsky 60-70
- Zubrod 3-4 equals Karnofsky 10-50
- Karnofsky DA, Burchenal JH. (1949). "The Clinical Evaluation of Chemotherapeutic Agents in Cancer." In: MacLeod CM (Ed), Evaluation of Chemotherapeutic Agents. Columbia Univ Press. Page 196.
- Oken MM, Creech RH, Tormey DC, et al. (1982). "Toxicity and response criteria of the Eastern Cooperative Oncology Group". Am. J. Clin. Oncol. 5 (6): 649–55. doi:10.1097/00000421-198212000-00014. PMID 7165009.
- Lansky SB, List MA, Lansky LL, Ritter-Sterr C, Miller DR (1987). "The measurement of performance in childhood cancer patients". Cancer 60 (7): 1651–6. doi:10.1002/1097-0142(19871001)60:7<1651::AID-CNCR2820600738>3.0.CO;2-J. PMID 3621134.
- Buccheri G, Ferrigno D, Tamburini M. Karnofsky and ECOG performance status scoring in lung cancer: a prospective, longitudinal study of 536 patients from a single institution. Eur J Cancer. 1996 Jun;32A(7):1135-41.
- A table with the Karnofsky Performance Status.