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ANN ARBOR,
MI - Patients who develop melanoma
on their face, head or neck can have the same early-diagnosis surgical
procedure to see if their cancer might spread as patients whose
cancer is on less delicate areas of the body, a new study finds.
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The
body's lymphatic system, which can act as a
super-highway for cancer |
The report,
from a team at the University
of Michigan Comprehensive Cancer Center, opens the door for
many more melanoma patients to benefit from a potentially life-saving
technique called sentinel lymph node mapping. The results will be
published in the Archives
of Otolaryngology, a journal of the American Medical Association.
Many hospitals
already use sentinel lymph node mapping to assess the threat of
melanoma in patients with lesions on their arms, trunk or legs.
The technique shows whether cancer cells have entered nearby lymph
nodes and might spread further, and helps doctors and patients decide
how aggressive treatment should be.
But fear of
damaging the delicate nerves and blood vessels concentrated in the
head and neck has kept many physicians from using the technique
on patients with cancer on their scalp, face or neck - nearly one-fifth
of the 87,900 melanoma patients diagnosed each year. As a result,
many may be receiving inadequate treatment.
The new results,
from 80 patients treated through the U-M's noted melanoma
program and followed for at least a year after mapping, show
that the technique can be performed safely and yield the same information
in these patients as in others.
More than 96
percent of patients were successfully mapped, and 18 percent were
shown to have melanoma that had spread to a lymph node - giving
them a diagnosis much sooner than a standard routine examination
would have. The false-negative rate was 4.5 percent.
"These
results clearly show that patients with melanoma of the head and
neck can be accurately staged through sentinel lymph node mapping,
allowing very early detection of even minimal disease in the lymph
nodes," says author Carol Bradford, M.D., who directs the U-M
Head and Neck Oncology Program. "Although the technique is
the most challenging in these patients, we now know it can be done,
and done safely."
The authors
hope the technique will become standard for all appropriate melanoma
patients. But they caution that to be accurate, the procedure requires
a great deal of experience and expertise on the part of the team
of surgeons, nuclear medicine specialists and pathologists required
to carry it out.
"Sentinel
lymph node mapping is one of the most important advances in melanoma
management in the last decade, but there has been a question of
whether it can be applied to the head and neck," says co-author
Timothy M. Johnson, M.D., who heads the U-M Multidisciplinary Melanoma
Program that sees more than 1,300 new melanoma patients each year,
more than half the cases in Michigan.
"Our program
has evolved, in partnership with the private-practice physician
community, to provide optimal, high-quality state-of-the-art patient
care that is also cost-effective," Johnson explains. But, he
feels, the ability to perform sentinel lymph node mapping in head-and-neck
melanoma patients exists or could be developed at other major cancer
centers.
The technique
focuses on the lymphatic system, an interlaced network of vessels,
ducts, nodes and glands that carries disease-fighting immune system
components throughout the body.
But the lymphatic
system can also act as a kind of highway for melanoma cells, giving
them a direct route from the original skin tumor to the bloodstream,
which can carry them to other sites where they can form new tumors.
The rest stops on this highway are tiny bean-shaped structures called
lymph nodes, which gather and filter the lymph fluid that carries
foreign objects like bacteria, viruses and cancer cells.
Studies have
shown that patients whose cancer cells have entered their lymph
nodes have a much worse potential for survival. Melanoma kills 7,400
Americans each year, more than one person each hour. The average
five-year survival rate for melanoma patients is about 89 percent.
But once the cancer spreads to the lymph nodes, the survival rate
drops to a range of 13 percent to 70 percent, depending on how many
lymph nodes contain melanoma cells.
For years,
surgeons removed entire sections of the lymphatic system of many
patients with melanoma, just in case the cancer had spread. But
only about 10 to 20 percent of these patients actually turned out
to have cancer cells in their lymph nodes - so many had undergone
the invasive and potentially dangerous surgery for no real reason.
As a result, studies of patients who had a node dissection, as the
operation is called, didn't have a better chance of survival.
Sentinel lymph
node mapping can determine exactly which patients need node dissection
and further treatment such as interferon and radiation. It allows
doctors to see which lymph nodes drain the cancerous region, and
to determine if cancer has entered the lymph system yet.
The approach
starts with an injection of a radioactive tracer and blue dye near
the melanoma site. After giving the injection time to collect in
the lymph node, a handheld radiation sensor leads the team to the
region where the radioactivity has concentrated. The surgeon can
then make a tiny incision there, and look for signs of blue dye
entering the first lymph node or nodes. This helps locate the nodes
that should be removed and tested for the presence of cancer. Because
such nodes are the first stop for traveling cancer cells, they're
called "sentinel" nodes.
Mapping is
now part of the National Comprehensive Cancer Network's guidelines
for melanoma staging, and has become a standard part of care at
many centers. But many teams have shied away from mapping the lymph
nodes of patients with melanoma above the neck.
The lymphatic
system in the head and neck is especially complex, with nodes and
ducts interlaced with the crucial nerves and blood vessels that
allow muscles and organs to function. Lymph fluid from the scalp
may drain to hard-to-find nodes a foot below, deep in the neck.
And one false move with a scalpel could paralyze parts of the face
or shoulders.
The new results
show it can be done safely by an experienced team, and still be
effective.
The U-M team
found that in 80 patients with melanoma on their heads or necks
who had the procedure between 1998 and 2000, at least one sentinel
lymph node was successfully found in 77 (96.3 percent). The average
number of nodes identified was 2.18, and three quarters of them
were in the neck. The rest were near the ears, in what's called
the parotid region.
Although the
mapping procedure is a team-based effort, the successful removal
of the sentinel nodes relies on the skill of the surgeon involved.
Both surgeons in the study - Bradford and co-author Riley Rees,
M.D., a U-M plastic surgery professor - were experienced in head
and neck surgery before they began using the technique. No patients
in the study suffered damage to any cranial nerve, including the
facial nerve, or to neck structures.
In all, 17.5
percent of the patients who underwent mapping were found by pathologists
to have cancer cells in their nodes. All had node dissections, and
were followed for at least a year. The remaining patients, whose
nodes were cancer-free, were also followed for at least a year.
Twelve percent of them developed recurrent disease, but only three
patients had a recurrence in the area that had been mapped, giving
a "false negative" rate of 4.5 percent.
The positive
and false-negative rates from the U-M head and neck study are comparable
to those from other studies where head and neck melanoma patients
were included along with others, says Bradford, who is an associate
professor and division chief of head and neck surgery in the Department
of Otolaryngology at the U-M
Medical School.
"Based
on these results and other studies, we hope that sentinel lymph
node mapping becomes part of standard practice for all patients
with a melanoma more than 1 millimeter in depth," she says,
noting that she and her colleagues will continue to follow the study
participants for several more years to determine their long-range
experience.
Besides Bradford,
Johnson and Rees, the study's authors include lead author and otolaryngology
resident Cecelia Schmalbach, M.D., assistant professor of dermatology
Jennifer L. Schwartz, M.D., and former otolaryngology fellow Brian
Nussenbaum, M.D., now at Washington University in St. Louis.
Reference:
Archives of Otolaryngology, January, 2003
Special notes
on this release
For more information
on melanoma treatment at the U-M
Comprehensive Cancer Center, which is part of the U-M
Health System, call the Cancer AnswerLine at 800-865-1125 or
visit www.cancer.med.umich.edu/clinic/melclinic.htm.
Written
by: Kara Gavin
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