Overall Survival (OS)

Overal survival rates are one important measure of survival.


Different “yardsticks” are used to measure survival, and each has its own strengths and limitations. Overall survival, or OS, is a statistical term referring to the percentage of people in a group who are alive after a defined length of time – usually years. For instance, the 5-year overall survival rate may be reported for people with a particular cancer – in which case it is the percentage of people who are living 5 years after diagnosis or 5 years after the start of therapy.

5-year OS rates are reported for many cancers including high-grade lymphomas because those who survive 5 years are likely to be cured of their disease. In some slow growing and low-grade malignancies like follicular lymphoma, however, the 10-year overall survival may be more reflective of cure rates.

At a basic level, the overall survival can be reflective of cure rates, but this is not always the case. When information about cause of death is added in, this may be referred to as a corrected survival or cause-specific survival. Cause-specific survival has the potential to be quite different from overall survival. The cause-specific survival is considered a more valid way to estimate how much extra death there is due to the cancer itself in a group. For instance, consider a cancer that is mainly found in people who also have bad heart disease. If you only look at overall survival, the deaths from heart disease are included in the numbers, making survival appear lower than it would be for a person who has that cancer but not heart disease.


“The 5-year overall survival for stage II Hodgkin lymphoma is about 90 percent.” This means that of all patients with Hodgkin Lymphoma in the reported group, 90 percent lived at least 5 years after the cancer was diagnosed.


Survival rates are good tools, but in some ways, they are like yellowed newspapers – since they take years to develop, they are true for a specific time frame and reflect the treatment used at that time.

For a person starting a new therapy today a published 10-year overall survival rate may or may not be relevant.

Updated October 2015.

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