Biological and clinical considerations regarding the use of surgery and chemotherapy in the treatment of primary breast cancer

Numerous clinical trials are currently being implemented to evaluate the effectiveness of a variety of therapeutic regimens against primary breast cancer. There must be a rational biologic basis for the use of each component of the therapy. Principles upon which operation and systemic chemotherapy are employed in current trials are presented in this review. The basis for cancer surgery is undergoing a redefinition which is in keeping with present understanding of tumor biology. Anatomical principles of the past are being supplanted as a result of evidence indicating 1) breast cancer is predominantly a systemic disease at the time of diagnosis, 2) removal of a primary tumor affects host immunological mechanisms as well as residual tumor cell kinetics, 3) the role of lymphatics and lymph nodes differ from what had previously been promulgated, and 4) the significance of multicentricity is not as clear as might be presumed. Such considerations are giving rise to a new biological basis for cancer surgery. Several continuing surgical clinical trials being conducted by the National Surgical Adjuvant Breast Project (NSABP) should provide information which will substantiate or refute the justification for a change in oncologic surgical principles. A brief review of information regarding tumor cell kinetics, experiences with adjuvant therapy in animal model systems, and other considerations providing justification for the use of systemic adjuvant chemotherapy has been provided. From the spectrum of combined modality trials in progress throughout the world should come information within the next few years which will verify or repudiate not only concepts and principles upon which the use of adjuvant therapy is based, but the worth of those modalities presently representing our total therapeutic resources and upon which rest hope for the cure of breast cancer. Cancer 40:574–587, 1977.