Karnofsky Score For Performance Status

Karnofsky score

Created by Dr David A Karnofsky et al. in 1948, the Karnofsky score was designed to evaluate how able a cancer patient is to undergo chemotherapy and survive it. Clinicians employ the score along with other considerations, such as tumor size and location.

The original study evaluated the performance in patients receiving nitrogen mustard chemotherapy for primary lung carcinoma.

The KPS is used as a prognostic factor when deciding chemotherapy and is based on the functional status of the patient, with regard to the ability to undertake daily activities, with or without help.

Seven behaviour based questions have been empirically identified as improving the accuracy of the KPS when discussed in conjunction with the application of the score:

■ Weight loss;

■ Weight gain;

■ Grooming;

■ Difficulty walking;

■ Reduced energy;

■ Driving;

■ Working part time.

There are other similar performance status scores available, such as the Zubrod score, also known as the Eastern Cooperative Oncology Group (ECOG) Score, the scoring method preferred by the WHO.

In the case of pediatric patients, the ability to undergo chemotherapy is scored by the Lansky score.

KPS interpretation

Each of the items in the Karnofsky score for performance status is awarded a number of points, from 0 to 100, in 10 point increments, where 100 indicates a patient with normal condition and 0 indicates condition incompatible with life, as shown below:

■ 100 - Normal; no complaints; no evidence of disease.

■ 90 - Able to carry on normal activity; minor signs or symptoms of disease.

■ 80 - Normal activity with effort; some signs or symptoms of disease.

■ 70 - Cares for self; unable to carry on normal activity or to do active work.

■ 60 - Requires occasional assistance, but is able to care for most of their personal needs.

■ 50 - Requires considerable assistance and frequent medical care.

■ 40 - Disabled; requires special care and assistance.

■ 30 - Severely disabled; hospital admission is indicated although death not imminent.

■ 20 - Very sick; hospital admission necessary; active supportive treatment necessary.

■ 10 - Moribund; fatal processes progressing rapidly.

■ 0 - Dead.

Although the rank in the KPS (given by the number of points) is often explicit enough in regard to the patient’s performance, in some clinical settings, patients are also put in one of the three groups:

■ A (100 – 80);

■ B (70 – 50);

■ C (40 – 0).

This model is only limited by the fact that it doesn’t take into account any effects from adverse treatment reactions. The score often changes once the patient starts chemotherapy but this is not acknowledged with a new evaluation.

The interrater reliability and construct validity of the KPS have been analysed, showing weaknesses because the procedure is not standardized enough.

In the future, KPS might start being used in the assessment of the Quality of Life in cancer, however, further validation, before this can happen, is required.

Original source

Karnofsky DA, Abelmann WH, Craver LF, Burchenal JH. The Use of the Nitrogen Mustards in the Palliative Treatment of Carcinoma – with Particular Reference to Bronchogenic Carcinoma. Cancer. 1948; 1(4):634-56.

Other references

1. Schag CC, Heinrich RL, Ganz PA. Karnofsky performance status revisited: reliability, validity, and guidelines. J Clin Oncol. 1984; 2(3):187-93.

2. Péus D, NewPcomb N, Hofer S. Appraisal of the Karnofsky Performance Status and proposal of a simple algorithmic system for its evaluation. BMC Med Inform Decis Mak. 2013; 13: 72.