A study that sought to see
if a less invasive, less debilitating procedure could determine accurately how
far breast cancer has spread fell short of the safety threshold the researchers
The procedure, common for
women who receive chemotherapy before their tumour is removed, is known as
sentinel lymph node surgery. During the procedure, doctors try to identify and
remove only the lymph nodes that are most likely to be malignant, known as
The problem is that this
approach can miss cancer in nearby axillary lymph nodes, which are typically
found under the armpits, lead researcher Dr Kelly Hunt, chief of surgical
breast oncology at the MD Anderson Cancer Centre in Houston, and colleagues
Although having only the
sentinel nodes removed is a plus in terms of preventing crippling side effects
such as arm swelling, loss of shoulder movement and pain, the question remained
that if the sentinel nodes were cancer-free, did that mean the axillary lymph
nodes were also cancer-free, Hunt said.
To try to answer that
question, the researchers determined that if sentinel lymph node surgery missed
cancerous axillary nodes only 10% of the time, then the procedure could
be a good alternative for these women.
"We didn't quite make
that point," said Hunt. "The false-negative rate was 12.6%."
In the study, the overall
false-negative rate was based on the removal of two sentinel nodes.
However, Hunt's team did
find that when three sentinel lymph nodes were removed and two types of mapping
tests were used before the procedure, the false-negative rate did fall below 10%.
"This is a huge step
forward, because now we know we can use these surgical standards to make the
next step toward reducing the extent of axillary surgery," Hunt said.
Not all experts agree
Not all experts agreed with
that assessment. The authors of an accompanying editorial said that the
approach may only be beneficial for a small number of women with breast cancer.
"In patients who start
out with cancer in their underarm lymph nodes and get chemotherapy, sentinel
lymph node biopsy is only an accurate way of determining whether cancer is
still left in those lymph nodes if you find three or more sentinel lymph
nodes," said editorial co-author Dr. Monica Morrow, chief of breast
service at Memorial Sloan-Kettering Cancer Centre in New York City.
"Many women aren't
going to meet this criteria," she explained, because in most cases there
aren't three sentinel lymph nodes. "So, this applies to a relatively small
proportion of women – about a quarter of them."
In the future, when more
and better targeted drug therapy is available, sentinel lymph nodes surgery
alone might be applicable to more women, she added, and the editorial stated
that the less-invasive approach should not become standard practice at this
The report was published
online in the Journal of the American Medical Association, to
coincide with the presentation of the findings at the American College of
Surgeons meeting in Washington, DC
For more on breast cancer,
visit the American Cancer Society.
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