Estimating the proportion of immunes in censored samples: a simulation study

We review currently known results concerning the estimation of an 'immune' or 'cured' proportion, and testing for the presence of immunes, in censored survival data, suggesting that a firm theoretical foundation now exists for analysis. Two types of estimators, parametric and non-parametric, are discussed and compared with respect to their theoretical properties, and, by simulation, with respect to their small sample behaviour. Both estimators have advantages and drawbacks, but together provide powerful tools for the perceptive analysis of survival data with, or even without, immune individuals.