Women with early-stage breast cancer and one or two positive sentinel lymph nodes who undergo sentinel lymph node dissection (SLND) fare just as well as those who have the more aggressive axillary lymph node dissection (ALND). In addition, most women with small tumors could avoid ALND altogether if they elect to undergo breast-conservation therapy (BCT; lumpectomy and radiotherapy) rather than mastectomy.
“I think it’s really evident now that many patients we are seeing are very early stage; that the sentinel node procedure is picking up very small volumes of disease when the tumor has spread to the lymph nodes,” explained study coauthor Kelly K. Hunt, MD, FACS, of The University of Texas MD Anderson Cancer Center in Houston. “Sentinel lymph node surgery is less invasive, provides accurate staging, and improves the quality of life for patients.”
Several years ago, the American College of Surgeons Oncology Group (ACOSOC) conducted a groundbreaking study, the Z0011 trial, in which the researchers concluded that the standard practice of ALND after lumpectomy and positive sentinel node analysis was not mandatory for all women with small tumors. In reporting their results in February 2011, the researchers found that women with stage I or II breast cancer who had just one or two cancerous lymph nodes (sentinel) removed were as likely to be alive and free of cancer after 5 years as were women who had ALND, possibly because adjuvant therapies (chemotherapy and radiation) may kill cancer cells in the axillary lymph nodes.
But a question remained: Could changing practice by eliminating ALND really impact a substantial portion of the breast cancer patient population? For the current study, the aim was to better understand applicability of the Z0011 trial results to the patient population at The University of Texas MD Anderson Cancer Center and to determine what percentage of the breast cancer population might ultimately benefit from it.
This study involved 861 women treated at The University of Texas MD Anderson Cancer Center between 1994 and 2009 who met the Z0011 trial criteria—stage I or II breast cancer and one or two positive sentinel nodes. Researchers compared overall survival and disease-free survival rates for ALND versus SLND alone in women undergoing BCT or total mastectomy (TM).
Of the 861 patients, 188 (21.8%) underwent SLND alone. Of 488 patients (56.7%) who underwent BCT, 125 (25.6%) had SLND alone. Of 412 patients who underwent TM, 67 (16.3%) women had SLND alone. After adjusting for tumor stage, the research team found no significant differences in survival between women undergoing SLND alone or ALND in both populations. Further, after examining their breast cancer patient population with Z0011 criteria, they estimated that up to 75% of their patients could avoid ALND if they undergo BCT.
This research was published in the Journal of the American College of Surgeons (2013; doi:10.1016/j.jamcollsurg.2012.09.005).