Survival Quotient as a Method for Investigating Psychosocial Aspects of Cancer Survival

Abstract

Terminally ill cancer patients die at different rates and some of this variance is due to psychosocial differences. In order to discover this variance we developed the Survival Quotient, an index of relative longevity which is applicable across different tumor sites with widely differing life expectancies. The Quotient is based on the difference between Observed Survival, i.e., how long a patient lived from diagnosis to death, and Expected Survival, or how long he was expected to live when compared to a large series of deceased patients with the same tumor site. To obtain an estimate of Expected Survival for six cancer sites (lung, breast, stomach, colon, cervix, lymphoma), six detailed multiple regressions were done. To illustrate the procedure, only one site (lung) is used along with case samples. The Survival Quotient can be useful in research where it is necessary to assess the velocity of dying while controlling for biological differences and similarities.