A retrospective single-center study of women with early breast cancer has confirmed the findings of the landmark trial that changed the way surgeons manage minimal disease in the axillary lymph nodes.
The researchers, led by Kelly Hunt, MD, from the University of Texas M.D. Anderson Cancer Center in Houston, found no significant difference in disease-free or overall survival between patients who underwent sentinel lymph node dissection (SLND) alone and those who underwent the more extensive axillary lymph node dissection (ALND). The median follow-up for both groups was about 5 years.
Their results are published in the January issue of the Journal of the American College of Surgeons.
The women had clinical T1-2 breast cancer with 1 or 2 positive sentinel lymph nodes (SLNs), just like the women in the landmark Z0011 trial from the American College of Surgeons Oncology Group (ACSOG).
In their 2011 study, the ACSOG investigators declared that the less extensive axillary surgery does not diminish survival in women with early-stage disease who have minimal lymph node involvement. All women in the Z0011 trial had undergone breast-conserving therapy (BCT), and most had received systemic therapy.
Dr. Hunt and colleagues wanted to answer an intriguing question related to the Z0011 trial: What proportion of women with early breast cancer and minimal nodal involvement in real-world practice can skip ALND?
An "examination of our breast cancer patients with Z0011 trial criteria suggests that almost 75% of SLN-positive patients would be candidates to avoid ALND if they undergo BCT," they write.
The recommendation to skip ALND in these early-stage breast cancer patients is limited to women who have undergone BCT, Dr. Hunt pointed out. "BCT patients [because of whole-breast radiation] will receive some treatment to the axillary nodes from the radiation fields used to treat the breast," she told Medscape Medical News in an email.
Theoretically, women with these low-risk disease characteristics who choose mastectomy — instead of BCT — might also be advised to skip ALND. Thus, the percentage of women who could benefit from less extensive surgery would be even higher.
But Dr. Hunt noted that "most of the early-stage breast cancer patients undergoing mastectomy will not receive radiation." That is a problem because "we don't know for certain that the radiation is the key" to the survival results seen in the Z0011 trial, she said.
"We are not yet ready to extend the trial results beyond that group of patients [who received BCT]," she said.
Both BCT and Mastectomy Patients Were Reviewed
This study involved 861 women treated at the M.D. Anderson Cancer Center from 1994 to 2009 who met the Z0011 trial criteria.
Of the 861 patients, 188 (21.8%) underwent SLND alone. Of the 488 patients (56.7%) who underwent BCT, 125 (25.6%) underwent SLND alone. Of 412 patients who underwent total mastectomy, 67 (16.3%) underwent SLND alone.
The BCT patients in this study had more T1 tumors than those in the Z0011 trial (76.0% vs 69.3%; P = 0.01), and more grade 2 to 3 tumors (87.3% vs 76.2%; P < 0.0001).
In the BCT and total mastectomy groups, after adjustment for tumor stage, Dr. Hunt and colleagues found no significant difference in survival between women undergoing SLND alone and those undergoing ALND.
"We are not saying that ALND should be eliminated, but we should use it more wisely so that all these other women, a huge percentage of patients we are treating, do not have to suffer the long-term debilitating consequences of that aggressive procedure," Dr. Hunt said in a press statement.
Study funding was provided by the Hamill Foundation. The authors have disclosed no relevant financial relationships.
J Am Coll Surg. 2013;216:105-113. Abstract
