https://surveillance.cancer.gov/statistics/types/survival.html
expressed as the proportion of patients alive at some point subsequent to the diagnosis of their cancer. Relative survival is an estimate of the percentage of patients who would be expected to survive the effects of their cancer. Observed survival is the actual percentage of patients still alive at some specified time after diagnosis of cancer. It considers deaths from all causes, cancer or otherwise. Overview of Population-based Cancer Survival Statistics describes the methodologies involved in calculating cancer survival statistics.