On the estimation of survival.

The advantages and disadvantages of the different methods for calculating survival according to the TNM (Topography, Lymph Node, and Metastasis) are described. Methods include the observed, relative, and conditional survival rates. For large cohorts, relative survival calculated by the life table method is most useful. Conditional survival, which requires long-term follow-up, is clinically the most informative. In addition, follow-up methods employed by tumor registries are considered.