[Concept of therapeutic ratio in radiation combined with chemotherapy]

Significance of combined therapy should be based in improvement of treatment results and decrease of side effects not only early but also late injuries. In other word, T.R. should be estimated whether direction of it is improvement or not. There are many different factors and difficult subjects which are decision of optimum dose, timing of combination, mechanism in synchronous combined therapy, distribution of tumor microcirculation. It is very important in order to improvement of T.R. clinically that we have been watching reactions after treatment closely and accumulating their datas.