SNB is used to check the one or more lymph nodes at greatest risk for breast cancer metastases. The procedure is considered a potential alternative to standard axillary node dissection (AND), which involves removing all of the lymph nodes in the armpit area and has been associated with chronic problems such as lymphedema (arm swelling caused by the blockage of lymph flow).
Large trials are under way to examine the safety and accuracy of SNB. However, the procedure is already gaining popularity, and there is concern that premature adoption of SNB as standard care may compromise these ongoing trials.
To examine patterns of SNB use in academic comprehensive cancer centers, Stephen B. Edge, M.D., of the Roswell Park Cancer Institute in Buffalo, N.Y., and his colleagues from the National Comprehensive Cancer Network looked at 3,003 women with stage I or stage II breast cancer who underwent SNB alone, SNB followed by AND, AND alone, or no axillary surgery at one of five comprehensive cancer centers between 1997 and 2000--the period SNB was entering clinical practice in the United States.
Use of SNB alone was associated with breast-conserving surgery. During the study period, use of SNB alone increased over time, from 8% in 1997 to 58% in the last half of 2000. There was an initial increase in the use of SNB plus AND until the last half of 1999. Use of SNB plus AND subsequently decreased as use of SNB alone increased.
"Widespread use of SNB in the routine care setting could affect accrual to and the generalizability of the results of ongoing clinical trials," the authors say, but they acknowledge that "delaying use of SNB pending trial results may lead to substantial morbidity including permanent lymphedema in a substantial proportion of invasive breast cancer patients."
They add that "whether widespread use of SNB represents good clinical judgment or an example of premature adoption of an inadequately tested new technology is a question that may only be resolved many years from now when, and if, the ongoing clinical trials of SNB provide definitive data on the outcomes of this technique."
In an accompanying editorial, David N. Krag, M.D., of the University of Vermont College of Medicine in Burlington, and Thomas B. Julian, M.D., of Allegheny General Hospital at the Drexel University School of Medicine in Pittsburgh, contend that use of SNB is not likely to impact accrual to trials because most of these trials have either already completed accrual or are expected to complete accrual within the next few months.
They add that "the results of ongoing clinical trials of SNB will be generalizable, because the patients on these trials have been entered in a well-stratified manner and represent a broad spectrum of clinical practices from across North America."
Contact: Deborah Pettibone, Roswell Park Cancer Institute, 716-845-8593; fax: 716-845-8362, deborah.pettibone@roswellpark.org; Kim Schwalje, National Comprehensive Cancer Network, 215-690-0252; fax: 215-690-0280, Schwalje@nccn.org.
Editorial: Carole Whitaker, University of Vermont, 802-656-1108; fax: 802-656-3203, carole.whitaker@uvm.edu.
Edge SB, Niland JC, Bookman MA, Theriault RL, Ottesen R, Lepisto E, et al. Emergence of sentinel node biopsy in breast cancer as standard-of-care in academic comprehensive cancer centers. J Natl Cancer Inst 2003;95:1514–21.
Editorial: Krag DN, Julian TB. Practice patterns of sentinel node biopsy at five comprehensive cancer centers. J Natl Cancer Inst 2003;95:1498–99.
Note: The Journal of the National Cancer Institute is published by Oxford University Press and is not affiliated with the National Cancer Institute. Attribution to the Journal of the National Cancer Institute is requested in all news coverage.
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