For the second time in three decades breast cancer surgery is in transition. The gold standard of axillary node dissection (AND) for regional lymph node staging surgery, established in the 1890s by William Halsted, is beginning to yield to sentinel lymph node biopsy (SLNB). The pace at which this is occurring across the United States varies with local surgical practice factors, practice venue, institution, and region. Surgeons in academic centers, large institutions, urban centers, and/ or states in which mean tumor size is less than 2 cm are much more likely to perform SLNB for breast cancer. That the large multicenter prospective randomized studies comparing SLNB and AND are many months to years away from reporting their initial analyses has not discernibly impeded a trend in favor of SLNB without confirmatory AND.A surgeon's perspective on SLNB for early breast cancer is influenced by many factors. Prominent among them are where in the country he or she practices, competitive pressures from peers and patients within his or her community, breast cancer stage distribution in his or her practice, and the weight accorded to regional nodal status by his or her medical oncology colleagues in decisions regarding adjuvant systemic therapy.Northeastern surgeons serve a population in which the incidence of regional disease (SEER staging systemprimary invasive cancer with regional nodal but no distant metastases) is relatively low. In the mid-to late1990s, the percentage of invasive breast cancer presenting as regional disease in New England (Connecticut, Massachusetts, Rhode Island, and Vermont) ranged from 24.0 to 28.0% [1][2][3][4]. By comparison, that in southern states (Mississippi, North Carolina, South Carolina, and West Virginia) was 27.6-32.4% [5][6][7][8]. Abandonment of AND for SLNB may well be more prevalent in states and regions with lower rates of regional stage breast cancer.There are large variations within individual states in incidence of regional breast cancer. Whereas in Florida in 2001 the incidence was 28.9%, among over 500 new breast cancer patients seen that year at the Sylvester Comprehensive Cancer Center (a private University facility), Jackson Memorial Hospital (a large inner city public hospital adjacent to Sylvester) and the University of Miami/Jackson Memorial Medical Center (UM/ JMMC-unduplicated data for both facilities) the incidence was 37.9, 44.3, and 41.7%, respectively (Florida Cancer Data System, courtesy of Jill McKinnon). In all but 3 years in the decade 1993-2002, at least 40% of new cases at UM/JMMC were regional stage. In 2 of the other 3 years (1995 and 1997) the incidence exceeded 50%. In 2002, the most recent year for which complete data are available, the incidence stood at 43.4%.Significant differences among American medical oncologists in whether or how nodal status influences selection of systemic adjuvant therapy are also relevant. There are a number of scenarios in which nodal status often trumps primary tumor and other factors in dictating the use of chemotherapy and ...