Surgery in the primary treatment of breast cancer.

Information available from NSABP protocols has contributed to an altered biological perception of breast cancer. The results of these studies lend support to a hypothesis which postulates that alterations in the loco-regional treatment of primary breast cancer will not change the natural history of the disease relative to distant metastasis and survivorship. Data from NSABP Protocol B-04 indicate that radical mastectomy provides no advantage over total mastectomy in clinically node-negative patients. Since 39% of this population had histologically positive nodes it may be concluded that leaving histologically positive nodes untreated results in no disadvantage. NSABP Protocol B-04 made available the scientific rationale for the study of breast-preserving operations in which the clinical significance of multicentricity will be determined. Although there is a sound scientific basis for the consideration of segmental mastectomy, there are no data available to justify the utilization of the procedure outside the context of a clinical trial. With the increased popularity and implementation of breast-preserving operations without the necessary supporting data, a potentially dangerous situation has been created which threatens to undermine the clinical trial process.