Danish Breast Cancer Cooperative Group (DBCG). A description of the register of the nation-wide programme for primary breast cancer.

An account of the criteria for protocol allocation and of the various treatments in the DBCG programme is given together with some numerical representations. Furthermore the article explains how the DBCG programme has been run, including its randomization. Finally there is a description of the calculation of recurrence-free survival and survival. It is concluded that in the nation-wide programme there are only minor methodological errors, and that the conclusions based on the therapeutic outcome of the different therapies are reliable.