ASCO: Survival No Better After Axillary Node Surgery
By Michael Smith, North American Correspondent, MedPage Today
Reviewed by Dori F. Zaleznik, MD; Associate Clinical Professor of Medicine, Harvard Medical School, Boston.
June 08, 2010
MedPage Today Action Points (Ann's NOTE: This is what they advise doctors to tell patients)
Explain to interested patients that axillary node dissection is often carried out after a sentinel node tests positive for breast cancer metastasis and sometimes when it is negative. Note that these studies clarify when such procedures are useful.
Note that this research suggests that routine removal of axillary nodes has little impact on survival.
Note that these studies were published as abstracts and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.
CHICAGO -- Routine removal of axillary nodes in breast cancer patients with lymph node involvement does not improve survival or lessen the risk of relapse, a researcher said here.
A randomized clinical trial involving more than 800 women found that performing axillary lymph node dissection in early-stage breast cancer patients whose sentinel node showed evidence of cancer spread had no impact on the risk of dying of the disease, according to Armando Giuliano, MD, of the John Wayne Cancer Institute in Santa Monica, Calif.
The procedure, widely viewed as necessary after cancer has been detected in the sentinel node, also made no difference in the risk of relapse, Giuliano told reporters at a press conference during the annual meeting here of the American Society of Clinical Oncology.
"The role of this operation should be reconsidered," said Giuliano, who was one of the pioneers of sentinel node biopsy in breast cancer.
Another major clinical trial looking at axillary node dissection, this one conducted among nearly 4,000 node-negative women, showed that node removal does not improve outcomes for those patients, said David Krag, MD, of the Vermont Cancer Center in Burlington.
In a third clinical trial reported at the meeting, researchers found that using more sensitive tests to detect sentinel node micrometastases in women with early stage breast cancer -- using an immune system assay, rather than chemical staining -- also did not predict survival.
On the other hand, women with such small metastases found by immunohistochemistry in the bone marrow were significantly more likely to die within five years of diagnosis, A. Marilyn Leitch, MD, of the University of Texas Southwestern Medical Center, told reporters.
Giuliano's axillary node study included 856 patients who had breast-conserving surgery and whole-breast radiation, with cancer found in the sentinel node by hematoxylin and eosin (H&E) staining after the surgery. They were randomized to get a further complete axillary node dissection or no surgery, Giuliano said, and followed for a median of 6.2 years.
The researchers found:
The five-year overall survival rate for patients undergoing sentinel node biopsy followed by axillary node dissection was 91.9% compared with 92.5% for sentinel node biopsy alone.
At the same time, disease-free survival was 82.2% and 83.8%, respectively.
The five-year recurrence of cancer in the breast was 3.7% after axillary node dissection and 2.1% after sentinel node biopsy alone.
Five-year recurrence of cancer in the lymph nodes was 0.6% and 1.3%, respectively.
None of the differences was statistically significant.
"We should be doing axillary node dissection much more selectively," Giuliano told reporters.
One limitation of the study was that it did not reach its accrual goals and thus was underpowered to detect differences, Giuliano said, although he told MedPage Today it's the largest such analysis ever performed in node-positive women.
Nonetheless, he said, it's unlikely that axillary node dissection -- which has significant morbidity -- is beneficial in all cases.
Many centers for years have avoided axillary node dissections in some patients, such as older women or those who would prefer to avoid the procedure, noted Eric Winer, MD, of Harvard Medical School. Winer was not part of the studies but moderated the press conference at which some of the data was presented.
"This study gives us more confidence to do that," he said, adding, "I don't think we should use this study to abandon node dissection in all patients."
"You can't say that this is a new standard," he told MedPage Today.
Krag's trial -- the National Surgical Adjuvant Breast and Bowel Project B-32 study -- looked at results from 3,986 women with node-negative early stage breast cancer who were randomized to either axillary node dissection or no further surgery.
The average time in study was 95 months, he said, but there were no significant differences in overall survival, disease-free survival, or regional control. On the other hand, there was significant residual morbidity at the end of follow-up:
19% of women in the axillary dissection group had a shoulder abduction deficit, compared with 13% in the other arm.
28% had more than a 5% difference in arm volume, compared with 17%.
31% had arm numbness, compared with 8%.
13% had arm tingling, compared with 7%.
All the differences were significant at P<0.001.
The implication, Krag said, is that when the sentinel node is negative, no further surgery needs to be done.
Indeed, Krag's co-investigator, Thomas Julian, MD, of Allegheny General Hospital in Pittsburgh, said that the finding confirms what is becoming standard practice. Since the 1990s, he told MedPage Today, physicians have been moving away from routine axillary node dissection in node-negative early stage breast cancers, although some procedures are still done.
Researchers in the third study were intrigued by the observation that some women with what seems like early stage breast cancer still develop distant metastases, Leitch said. They wondered if more sensitive testing might identify those at risk by finding tiny deposits of cancer cells in the sentinel node or in bone marrow.
To find out, they enrolled 5,539 women undergoing breast-conserving surgery, who had bone marrow aspiration and a sentinel node biopsy. If the sentinel node was negative after H&E staining, she said, the investigators used the immune system assay to look deeper.
They found that 24% of the nodes were positive for metastases on staining, and a further 10% came up positive on immunohistochemistry. At the same time, 3% of the bone marrow tests using the immune system approach came up positive, she said.
However, when the results were correlated with survival, there was little effect of using the immune system assay to retest the sentinel nodes, she said. On the other hand, the presence of bone micrometastases was significantly associated with an increased risk of death (at P<0.01).
"One of the surprises was the overall excellent survival in both groups," she said -- about 93% overall.
The practice among pathologists in the U.S. has been variable, Winer said, with many doctors opting to use the more sensitive tests.
The node-positive study was supported by the American College of Surgeons Oncology Group. Giuliano did not report any potential conflicts.
The node-negative study was supported by the National Cancer Institute. Krag reported no potential conflicts.
The immunohistochemistry study was supported by the American College of Surgeons Oncology Group. Leitch did not report any potential conflicts.
Winer reported financial links with Genentech.
Primary source: Journal of Clinical Oncology
Giuliano AE, et al "ACOSOG Z0011: A randomized trial of axillary node dissection in women with clinical T1-2 N0 M0 breast cancer who have a positive sentinel node" J Clin Oncol 2010; 28(7s): Abstract CRA506.