Assessment of response to therapy in advanced breast cancer.A project of the programme on clinical oncology of the International Union against Cancer, Geneva, Switzerland

I gramme on Clinical Oncology of the UICC to formulate a system for the evaluation of response to treatment of advanced cancer. It was considered that a single uniform system, used internationally, would be invaluable for the accurate comparison of published results from different centers. Advanced breast cancer was selected as the first tumor for consideration because a number of different evaluation methods were already in use, 1-6, and it was felt that agreement on a common system might readily be achieved. A preliminary document describing such a system was prepared which was then circulated to many workers in the field for comment, after which it was revised accordingly. The final document is now presented below. It is hoped that this system will be widely adopted and that it may eventually be used as a model for the assessment of therapy of other tumors.