Relation between appropriateness of primary therapy for earlystage breast carcinoma and increased use of breast-conserving surgery

Background Breast-conserving surgery is a more complex treatment than mastectomy, because a separate incision is needed for axillary lymph-node dissection, and postoperative radiotherapy is necessary. We postulated that adoption of this therapy into clinical practice might have led to discrepancies between the care recommended and that received. Methods We used records of the US national Surveillance, Epidemiology, and End Results tumour registry to study 144 759 women aged 30 years and older who underwent surgery for early-stage breast cancer between 1983 and 1995. We calculated the proportion undergoing at least the minimum appropriate primary treatment (defined, in accordance with the recommendations of a National Institutes of Health Consensus Conference in 1990, as total mastectomy with axillary node dissection or breastconserving surgery with axillary node dissection and radiotherapy) during each 3-month period. Findings The proportion of women receiving appropriate primary therapy fell from 88% in 1983-89 to 78% by the end of 1995. This decline was observed in all subgroups of age, race, stage, and population density. Of all women in the cohort, the proportion undergoing an inappropriate form of mastectomy remained stable at about 2·7% throughout the study period. The proportion undergoing an inappropriate form of breast-conserving surgery (omission of radiotherapy, axillary node dissection, or both) increased from 10% in 1989 to 19% at the end of 1995. Interpretation Although most women undergo appropriate care, the appropriateness of care for early-stage breast cancer in the USA declined from 1990 to 1995. Because the proportion of all women who were treated by breastconserving surgery increased, and because this approach was more likely than was mastectomy to be applied inappropriately, the proportion of all women having inappropriate care increased.