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.
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.
Reference: Archives of Otolaryngology, January, 2003
Journal
Archives of Otolaryngology - Head and Neck Surgery