Progression Free Survival (PFS)

Definition of Progression-Free Survival and What it Means

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Progression-free survival (PFS) denotes the chances of staying free of disease progression for a group of individuals suffering from a cancer after a particular treatment. It is the percentage of individuals in the group whose disease is likely to remain stable (and not show signs of progression) after a specified duration of time. Progression-free survival rates are an indication of how effective a particular treatment is.

Progression-free survival is often calculated for treatment of diseases that are slow-growing and difficult to cure, like low-grade lymphomas. This term is also used when salvage treatments are offered in situations where the intention is not cure but the control of disease.

In the case of this statistic, survival doesn't simply mean that the subjects were still alive. It means that they were alive and their disease or condition was stable and not progressing. It doesn't give the overall survival rate or how long the group actually lived after treatment.

Examples of Use of Progression-Free Survival Statistics

Please note that the example is not an actual current statistic.

  • 'The 1-year disease-free survival for stage IV Hodgkin lymphoma is 30% when treated with a new combination of drugs.'

This means that after this particular treatment is offered, about 30% of those treated with this new combination will have stable disease without progression at 1 year.

Use of Progression-Free Survival Statistics in Medical Research

You may see the term used in statistics reported in a research paper comparing two different treatments. When the treatments are intended to halt progression of a condition rather than to eliminate symptoms or cure it, the progression-free survival rate may be the main measure of showing which treatment is best.

A higher percentage of progression-free survival shows that more of the study participants were stable in their condition at the end of the stated time period. A percentage of 90% is better than 30%.

A longer progression-free survival period shows a longer period of stability. Studies may continue for several years and show the progression-free survival rate at 1 year, 2 years, etc.

Different progression-free survival rates may be given for different populations, such as men, women, children, seniors, ethnic groups, and groups with co-morbid conditions (such as diabetes with lymphoma).

What Progression-Free Survival Doesn't Tell You

Being progression-free doesn't mean that the cancer has been cured or that it is no longer producing symptoms. It means that it isn't progressing further. The number is only a statistic for the time period stated and doesn't necessarily predict what will happen in the future.

Survival statistics can't predict individual survival, they only are an indicator that a treatment is more or less effective than other treatments on average.

Your condition may remain progression-free for a longer or shorter time than the average that was found in various studies. Discuss your individual situation with your health care team. They will weigh many factors in deciding which is the best treatment for your individual case. You can ask them why they chose one option over another in your case.

Source:

NCI Dictionary of Cancer Terms, National Cancer Institute, Accessed 2/24/2016.

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