Importance of Prognosis With Cancer

doctor talking to patient about her prognosis with cancer
What is meant by the term prognosis?. istockphoto.com

You may have heard your doctor talk about the prognosis of your cancer (or other medical condition). What is the definition of prognosis, and what do you need to know about prognosis to make the best decisions for your healthcare? Let's talk about how prognosis is determined, and the limitation of the statistics used, especially in this era when treatments are improving.

Prognosis: Definition

Prognosis is a prediction or estimate of the chance of recovery or survival from a disease. Most physicians give a prognosis based on statistics of how a disease acts in studies on the general population. What this means is that your prognosis is not something written in stone. It is an estimate or guesses about how you will do, but generally, some people will do much better and some people will do worse than what is "average." There are few people who are "average" when it comes to their health.

Prognosis with cancer can depend on several factors, such as the stage of disease at diagnosis, type and subtype of cancer, the molecular profile of the tumor, and even gender.

Prognosis Is a Statistic

Most information you will hear and read about the prognosis of your disease is based on statistics from studies looking at other people. It’s important to note that these numbers are only numbers, and do not look at individual variations.

Most statistics are also somewhat dated. For example, statistics looking at the 5-year survival rate for a particular disease may be several years old—and since the time they were reported, newer and better treatments may have become available. Lung cancer is an example where the "prognosis" of the disease may not be very accurate.

Many of the statistics we use that talk about survival are several years old. Yet, more new drugs have been approved for the treatment of lung cancer in the past five years than in the 40 years preceding that time.

Prognosis is Different for Everyone With Cancer

Every single cancer is different. If there are 200 people with stage 2A non-small cell lung cancer in a room, there are 200 cancers that differ in molecular profiles and other important variants. On top of this, every person has important differences that affect prognoses, such as age, general health, co-existing medical conditions, and ability to tolerate treatment. Look at some of the many factors that can affect survival rate for people with lung cancer.

Terms Used to Describe Prognosis With Cancer

There are many terms that your doctor may use in talking about your prognosis. Some of these are more likely to be used than others based on the expected survival with a cancer. Other terms are used more often as parts of clinical trials. Some of these terms include:

Survival rate: The survival rate is the "average length of time someone is expected to survive cancer, and is usually given based on a period of time, for example, “the 5-year survival rate.” 

Median survival rate: The median survival rate is a number which defines the time after which half of the people with a certain type and stage of cancer are alive, and 50 percent have died. With more aggressive tumors, such as lung cancer, prognosis is often described in this way.

Progression-free survival: Progression-free survival or PFS is usually used to describe the response to a treatment for cancer, and refers to the average amount of time during which cancer does not grow, or remains stable. For treatments that control a cancer, rather than cure the disease, progression-free survival can be a measure to see how long a treatment may work (before a cancer becomes resistant to the treatment).

PFS is often used when describing treatments such as targeted therapies for cancer.

Disease-free survival: Disease-free survival refers to the length of time that someone remains free of detectable cancer.

Overall survival: Overall survival refers to the average length of time someone survives after a diagnosis of cancer before death from any cause including cancer.

Improving Your Prognosis

Aside from treatments your doctor recommends, there are some things you can do yourself to improve your prognosis. Keep in mind that some people may succumb to a disease despite every effort to fight it, while others do well almost without trying. That said, there are some things individuals can do to raise their odds. Finding support from friends or in a cancer community or participating in regular exercise have both been found to improve survival for some people with some forms of cancer. 

A Word of Caution 

It's important to again point out what prognosis means. Since it is a statistic it is an estimate of how someone will do based on the average outcome of a group of people. Just as we know that everyone is not the same height and weight, we know that averages sometimes say little for an individual person. Yet with cancer, there are even more variables factored in than those that determine height. It is also a statistic derived from past experience. Statistics may tell you how the "average" person did with cancer similar to yours (but of course molecularly different) at a time when treatments may be different than they are today.

If you have been diagnosed with cancer, after understanding the limitations in estimating prognosis, there is one more step that some people have found helpful. Try reframing the statistics in your mind. For example, instead of thinking that 40 percent of people do not survive for five years with particular cancer, realize that 60 percent of people do survive. And keep in mind that the statistics—those numbers we use to estimate prognosis—will look different five years from now than they do today.​​

Also Known As: survival rate 

Examples: Jill was given a good prognosis for recovery from her lung cancer since it was found at such an early stage

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