Early adoption and disturbing disparities in sentinel node biopsy in breast cancer.

Axillary lymph node surgery remains an integral component of breast cancer treatment. Node status provides key prognostic information that is used to direct adjuvant systemic therapy (1). Removal of the nodes may also improve local control, although the preponderance of data shows no survival advantage with node dissection itself (2). Until recently, surgery required full axillary lymph node dissec-tion (ALND). However, recovery from ALND is painful, and the procedure carries the risk of permanent lymphedema. In the early 1990s, it was hypothesized that colloidal material injected into the breast would drain to the same fi rst node(s) as the cancer (3 , 4). The commonly used agents are radiolabeled sulfur colloid alone or in combination with a blue dye (isosulfan blue or methylene blue), which are detected by a hand-held gamma probe or by visual iden-tifi cation of blue-stained nodes. Early confi rmatory studies proved that this procedure, termed " sentinel lymph node biopsy " (SLNB) for those fi rst nodes " standing guard " in the axilla, was accurate in that sentinel node was positive in all but a few women who had any positive nodes on subsequent ALND (5 , 6). It was therefore felt that a negative SLNB could make ALND unnecessary. In 1999, two National Cancer Institute (NCI) – sponsored trials (National Surgical Adjuvant Breast and Bowel Project [NSABP] B-32 and American College of Surgeons Oncology Group [ACOSOG] Z-0010) opened to fully defi ne the accuracy of SLNB and to determine if omission of ALND in patients with a negative SLNB would affect survival. Although the NCI considered SLNB investigational, its obvious advantages in tolerability and morbidity led to its increasing use outside the clinical trials. Indeed, a study of practice at fi ve NCI-designated centers showed that SLNB was used in place of ALND even before the trials started. These centers entered few women on the randomized NSABP study (7). In this issue of the Journal, Chen et al. (8) identify a similar pattern of increasing use of SLNB in a national population sample of 491 000 women with stage I and II disease who were treated between 1998 and 2005. In 1998, 27% of the women received SLNB without ALND, and this proportion increased to 65% in 2005. The authors did not report how many of these women entered the NCI-sponsored trials, but the 7500 women with SLNB on the trials could account for …