A person who had the cancer and died 10 years later of the cancer would contribute an event, a death due to the cancer, having also contributed 10 person-years of survival time. A 90 % cancer specific survival at 10 years would mean that 90 % of patients had not died from their cancer, while 10 % had died from their cancer (Kaplan, 1958). Calculation of cause-specific survival is especially important when studying diseases with a favorable prognosis, as is the case at hand, where the patients live long enough to be exposed to other causes of death
