The five-year survival rate is a type of

survival rate Survival rate is a part of survival analysis. It is the proportion of people in a study or treatment group still alive at a given period of time after diagnosis. It is a method of describing prognosis in certain disease conditions, and can be use ...

for estimating the

prognosis Prognosis ( Greek: πρόγνωσις "fore-knowing, foreseeing") is a medical term for predicting the likely or expected development of a disease, including whether the signs and symptoms will improve or worsen (and how quickly) or remain sta ...

of a particular disease, normally calculated from the point of diagnosis. Lead time bias from earlier diagnosis can affect interpretation of the five-year survival rate. There are absolute and relative survival rates, but the latter are more useful and commonly used.

Relative and absolute rates

Five-year relative survival rates are more commonly cited in

cancer Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal b ...

statistics. Five-year absolute survival rates may sometimes also be cited. * Five-year ''absolute'' survival rates describe the percentage of patients alive five years after the disease is diagnosed. * Five-year ''relative'' survival rates describe the percentage of patients with a disease alive five years after the disease is diagnosed, divided by the percentage of the general population of corresponding sex and age alive after five years. Typically, cancer five-year relative survival rates are well below 100%, reflecting excess mortality among cancer patients compared to the general population. In contrast to five-year absolute survival rates, five-year relative survival rates may also equal or even exceed 100% if cancer patients have the same or even higher survival rates than the general population. The pattern may occur if cancer patients can generally be cured, or patients diagnosed with cancer have greater socioeconomic wealth or access to medical care than the general population. :

The fact that relative survival rates above 100% were estimated for some groups of patients appears counterintuitive on first view. It is unlikely that occurrence of prostate cancer would increase chances of survival, compared to the general population. A more plausible explanation is that the pattern reflects a selection effect of
PSA screening Prostate cancer screening is the screening process used to detect undiagnosed prostate cancer in men without signs or symptoms. When abnormal prostate tissue or cancer is found early, it may be easier to treat and cure, but it is unclear if ear ...
, as
screening Screening may refer to: * Screening cultures, a type a medical test that is done to find an infection * Screening (economics), a strategy of combating adverse selection (includes sorting resumes to select employees) * Screening (environmental), ...
tests tend to be used less often by socially disadvantaged population groups, who, in general, also have higher mortality.

Uses

Five-year survival rates can be used to compare the effectiveness of treatments. Use of five-year survival statistics is more useful in aggressive diseases that have a shorter life expectancy following diagnosis, such as

lung cancer Lung cancer, also known as lung carcinoma (since about 98–99% of all lung cancers are carcinomas), is a malignant lung tumor characterized by uncontrolled cell growth in tissues of the lung. Lung carcinomas derive from transformed, mali ...

, and less useful in cases with a long life expectancy, such as prostate cancer. Improvements in rates are sometimes attributed to improvements in diagnosis rather than to improvements in prognosis. To compare treatments independently from diagnostics, it may be better to consider survival from reaching a certain stage of the disease or its treatment. Analysis performed against the Surveillance, Epidemiology, and End Results database (SEER) facilitates calculation of five-year survival rates.

References

{{reflist, 30em Medical terminology Epidemiology