Calculation of survival rates by the life table and other methods

The last few years have seen the introduction of medical statistics into the curriculum for MB, BS and for the FFR. Also, an increasing number of clinical trials have considered statistics at the planning stage of the trial, rather than only at the end point. However, there is one particular aspect of medical statistics which has consistently been neglected, namely, technique in calculating survival rates for cancer patients. All too often, a direct method of calculation, see section 3.1, is used when a life table method would provide a better estimate. The life table, or actuarial method, was first described in a medical context by Greenwood (1926), and later by Merrell and Shulman (1955) and Cutler and Ederer (1958). It has however, not been explained in detail in a British journal. The objective of the present paper is to remedy, this fact so that it can be used more widely in the future in preference to a direct method.