Ultrasound-guided biopsy could save thousands of unnecessary operations
for melanoma patients
6 October 2007
A less-invasive technique to biopsy lymph nodes using an
ultrasound-guided fine needle showed a high success rate in identifying
cancer. It could spare thousands of melanoma patients every year worldwide
from having to undergo unnecessary and sometimes unpleasant surgery to
verify whether their cancer has spread.
In a study presented at the European Cancer Conference (ECCO 14) in
Barcelona last month, scientists found that the less invasive technique
produced a false positive rate of only one percent, so that 99% of patients
with healthy lymph nodes were correctly classified.
The study, the largest of its kind to date, tested the accuracy of the new
technique in 590 patients with recently diagnosed melanoma who underwent an
ultrasound of the lymph node region near their tumours before having the
sentinel lymph node cut out for examination. If the ultrasound confirmed
cancer or looked suspicious, patients also underwent the fine needle
aspiration biopsy before the sentinel node surgery. Survival was tracked for
an average of 28 months.
“The fine needle aspiration detected tumour cells
in the lymph node of half of the patients who were later shown to have
node-positive disease through the surgical sentinel node biopsy procedure.
In nearly all the cases that it missed, the tumour deposit in the sentinel
node was very small and those patients seem to have an excellent prognosis —
their survival seems similar to that seen in patients with no spread to the
lymph nodes,” said the study’s leader, Dr Christiane Voit, a dermatologist
and head of the diagnostic unit at the Skin Cancer Center at Charité –
Universitätsmedizin Berlin, the Medical University of Berlin, Germany.
"This study shows that the technique is highly accurate and we are
recommending that it should now be performed routinely before automatically
performing sentinel lymph node biopsies, as a way to reduce the need for
unnecessary sentinel node operations," he said.
Whether cancer has spread
to the lymph nodes is the most important factor influencing the prognosis
and treatment plan for patients with melanoma. Lymph node surgery for tumour
staging has become more refined and less debilitating over the last decade.
Traditional operations involve the removal of all lymph tissue from the area
that drains the site of the tumour, but in some cancers, including melanoma,
doctors now more often cut out only one or two key nodes, called sentinel
nodes. If the sentinel node is free of cancer, patients don’t need to have
more extensive lymph node removal.
However, only 20% of patients who have
their sentinel lymph nodes excised have cancer that has spread there, so the
operation, which can still be accompanied by side effects such as chronic
swelling and seroma, is unnecessary for 80% of patients.
biopsy (the excision of only one node instead of all regional lymph nodes)
is already an improvement over complete removal of all the lymph nodes in
the axilla, groin or neck, but we still need a better way to identify which
patients need their sentinel lymph nodes cut out and which don’t, so that
all those patients who are subjected to unnecessary surgery can avoid it.
Ultrasound-guided fine needle aspiration does look better,” said Voit,
adding that the procedure does not cause the side effects seen in sentinel
node biopsy. The sometimes-claimed danger of spreading of tumour cells along
the needle tract was not evident in this study, nor in previous studies the
group has conducted using the method, Voit added.
The technique, called
ultrasound-guided fine needle aspiration cytology, or US-FNAC, has been
reported to be useful in replacing the need for a sentinel node biopsy in
breast cancer, but has not yet been accepted as a valuable option to avoid
surgical sentinel node biopsy in melanoma.
Source: European Cancer Organisation
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