GRACE :: Cancer Basics


FAQ: What is “Performance Status” and Why Does it Matter so Much?


Along with a patient’s age, sex, and past and current medical issues, performance status (PS) is one of the most important factors that is categorized for patients. It essentially refers to a patient’s ability to manage his or her activities of daily living — things like bathing, dressing, feeding yourself, etc., as well as general activity level and ability to do whatever work they need to do. 

There are two leading scales for measuring PS. The most frequently used one, known as the Zubrod or ECOG scale,  simply goes from 0 to 4, with 0 representing no symptoms or limitations, and 4 representing being bedridden and completely unable to care for yourself.  

Zubrod PS


The alternative is called the Karnofsky PS scale, describing the range of activity from fully functional (100%) down to 10%, bedridden; obviously, this is essentially the same range, but with finer grading, as if you could assign half points on the Zubrod scale. Here’s the description of the levels on the Karnofky scale:

Karnofsky Performance Status PS Scale

Though this scale suggests that there is a clear number for everyone, it is more fair to acknowledge that PS is somewhat in the eye of the beholder.  Certainly, one person’s 70% Karnofsky PS may be 60% to someone else, and this may depend on how well a person happens to be doing on a given day at a given hour.  This may be part of why the Zubrod PS scale is more widely used: it doesn’t put too fine a point on a subjective measure.

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Cancer 101 FAQ: I have metastatic cancer, but why can’t it just all be surgically removed, or radiated?


One of the most common questions that emerges in a person’s first foray into metastatic cancer is often, “Why can’t a surgeon just resect all of the areas of disease?”, or a related one of “why can’t we just radiate every area of metastatic spread?”. The concept is appealing, as people would hope to remove or destroy every area of visible disease and be rid of it and cured. The problem is that metastatic cancer represents a situation in which the disease we can see is almost always accompanied by additional micrometastatic disease we can’t see, but that remains under the surface and able to create new areas of metastatic spread that prevent even our most aggressive local therapies (those directed to disease in a particular area, as opposed to systemic therapies that reach throughout the body) from being truly curative. If cure is achieved by ridding the body of any viable cancer, removing or radiating even 98 or 99% isn’t going to do the job if there is more disease below our levels of detection.

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