[Japan Clinical Oncology Group for cooperative cancer clinical trials and role of the statistical center in the management of cancer clinical trials].

In 1978, clinical investigators decided to collaborate on clinical trials through a "cooperative group" mechanism in order to promote multidisciplinary treatment of cancer under the auspices of a Grant-in-Aid for Cancer Research from the Ministry and Health and Welfare. This cooperative study group was formally renamed in 1990 and became "The Japan Clinical Oncology Group (JCOG)," and its Statistical Center was housed in the National Cancer Center Hospital. This paper introduces various JCOG activities and the role of the Statistical Center.