Controversies in Treatment Spur Another Look at Z11

Ben Leach
Published: Wednesday, Nov 30, 2011
Sentinel Lymph Node For years, surgeons were taught that removing any and all cancerous tissue greatly reduced the risk of cancer recurrence. However, the notion that “to cut is to cure” is being challenged by a study that suggests that there is no difference in survival among patients with breast cancer who did not undergo a recommended surgical treatment.

The American Society of Clinical Oncology (ASCO) guidelines currently recommend that all cancerous lymph nodes be removed from under the arm in an effort to prevent the recurrence of cancer.

Before operating, a sentinel lymph node biopsy (SNB) is typically performed on patients with T1 or T2 breast cancer to determine whether any of the lymph nodes are cancerous. If no positive nodes are identified in the SNB, the chance of other lymph nodes being cancerous is very low, and only a sentinel lymph node dissection (SLND) is performed.

However, a positive sentinel node typically indicates a likelihood that other positive nodes exist, prompting an axillary lymph node dissection (ALND). This has been standard practice as reflected in the ASCO guidelines that currently state, “…the Panel recommends routine ALND for patients with a positive SNB on the basis of routine histopathologic examination.”

TABLE 1. Survival Outcomes of the Z11 Study

Median Follow-Up Years: 6.3
  DFS OS
SN 83.9 (80.2–87.9%) 92.5 (90–95.1%)
ALND 82.2 (78.3–86.3%) 91.8 (89.1-94.5%)
HR 0.82 (0.58–1.17) 0.79 (.56–1.1)
Adapted from Giuliano et al. JAMA. 2011;305(6):569-575.

ALND indicates axillary lymph node dissection; DFS, disease-free survival; HR, hazard ratio; OS, overall survival; SN, sentinel node.
A hotly debated study that was released in 2010 might eventually prompt changes to the ASCO guidelines. The American College of Surgeons Oncology Group (ACOSOG) Z11 randomized trial, published in the September 2010 issue of Annals of Surgery, found that survival rates were similar in patients with early-stage breast cancer with 1or 2 positive sentinel lymph nodes who underwent SLND and whole-breast irradiation (WBI) compared to those who underwent ALND with WBI (TABLE 1). These findings suggest that SLND without ALND could be a reasonable treatment option even in node-positive breast cancer patients. The median overall survival at 5 years was 91.8% in those who underwent ALND and 92.5% in those who were observed after SLND. Disease-free survival was 82.2% in patients with ALND and 83.9% in patients with SLND.

Monica Morrow

Monica Morrow, MD

“What that tells us is that axillary dissection is not necessary for local control and does not contribute to survival,” said Monica Morrow, MD, chief of Breast Service at Memorial Sloan- Kettering Cancer Center in New York City, who presented on Z11 at the 10th International Congress on the Future of Breast Cancer, held in August 2011 in Coronado, California.

“When you looked at disease-free survival or overall survival, there was also no statistically significant difference between the two groups,” said Morrow.

Morrow remarked on the unusually low recurrence rates among patients in the Z11 study (TABLE 2). Only 2 patients (0.5%) in the dissection arm (n = 420) and 4 patients (0.9%) in the sentinel-node-only arm (n = 436) experienced any kind of regional recurrence during a median follow-up of 6.3 years.


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Online CME Activities
TitleExpiration DateCME Credits
Community Practice Connections™: 16th Annual International Congress on the Future of Breast Cancer®Sep 29, 20182.0
School of Breast Oncology®: Mid-Year Video Update OnlineSep 30, 20182.0
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