HESC 401 Chapter Notes - Chapter 6: Cohort Study, Cancer Staging, Life Table
Document Summary
To compare five different ways of describing the natural history of disease: case-fatality, five-year survival, observed survival, median survival time, and relative survival. To describe two approaches for calculating observed survival over time: the life table approach and the kaplan-meier method. To illustrate the use of life tables for examining changes in survival. To describe how improvements in available diagnostic methods may affect the estimation of prognosis (stage migration). Number of deaths divided by the person-years of which a group is observed. However, person-years can be problematic since person years vary from year to year; a person-year for an individual will change as time progresses due to effectiveness (or lack thereof) of treatment). Good for randomized trials and cohort studies. Percentage of patients who are alive 5 years after treatment begins or 5 years after diagnosis: this is a proportion, not a rate, used for evaluating treatments for cancer.
