[A nonparametric estimation of survival curve with interval censored data]

Although survival analysis dealing with right-censored data has enjoyed wide use, analysis of data with left-censored and interval censored cases is available only to a very limited number of clinical researchers because of the difficulty in understanding the concepts and performing the calculations. This paper applies Turnbull's self-consistency algorithm, which he applied in his paper on survival data with only left-censored cases, for nonparametric estimation of survival curve including both left and interval censored data. A difference in the estimates of survival rate among different modes of calculation was demonstrated using the data from the Hematopoietic Cell Transplantation Registry of the Japan Society for Hematopoietic Cell Transplantation, which illustrated the necessity of a correct analysis.