[Recent progress of clinical trials in urologic oncology]

In Japan, after New Good Clinical Practice put into operation, it has became improved the environment of conducting clinical trials for new drug approval. Clinical trial supporting system, such as data management system, have been developing. It is important to introduce the know-how into clinical trials that is not for new drug approval. Randomized controlled clinical trials are considered to be high evidence level study design. In some fields, it is very difficult and is not appropriate to conduct randomized controlled trials. In such fields, it is appropriate for well designed descriptive studies. And it should be accepted as high evidence level study for well designed descriptive studies. For cytostatic antineoplastic agents, it should be introduced new evaluation method such as randomized discontinuation design.