Survival rate

The survival rate is the percentage of patients who live a certain time after being diagnosed with a disease. This term is used mainly in cases of diseases that have a poor prognosis because they cause high mortality in a given period, as occurs in the case of cancer. Five-year survival rates are used to establish conventional criteria for establishing prognosis.

The inverse of the survival rate is the death rate.

Because the 5-year rates are based on patients diagnosed and initially treated more than 5 years ago, they are likely no longer accurate today. Treatment improvements often result in a more favorable prognosis for newly diagnosed patients.

Types

The survival rate can be of two types:

• Relative survival rate or specific to five years: Excludes from statistical calculations to patients who have died due to other diseases, and it is considered to be a more precise way to describe the prognosis of patients with particular types and stages of cancer (although for another reason it does not imply that in that period it could not have died of that particular disease).

• Global survival rate or at five: It refers to the percentage of live patients after five years, regardless of the cause of death.

Relative survival rate is also defined as the ratio between observed survival and expected survival in the general population for the same age, same sex, and same country. This allows survival rates to be compared between different countries and is used in large multinational databases, such as SEER in the US or EUROCARE in Europe. Its estimation requires having the life tables of the corresponding population, and its interpretation is closer to overall survival than to specific survival.