[A statistical study on the survival rate].

The survival rate is used as a criterion in evaluation of cancer treatment. This paper describes several view of various calculating methods for the survival rate by using a computer filing system of patients' records of cancer therapy as follow; Crude survival rate should not be used in usual follow-up study, if possible, because different results obtained from different determination for right censored cases. In case of value of the life table method or relative survival rate changed in short terms, re-computation by the more short interval (for example, from yearly monthly) must be analyzed for the reason of the quick exchange. According with improvement of the survival rate of cancer therapy, it is important to remark for the complication of normal tissues by radiation therapy at the end of treatment and during follow-up observation. Therefore, we proposed a new concept which is named "Cumulative effective survival rate" and is calculated by multiplying the average of cumulative weighted factors of complications of various normal tissues to the relative survival rate.