By Catherine Grillo

When Susan Boucher was diagnosed with vulvar cancer‚ she knew how to do her homework. A nurse and high–level staffer at the American Cancer Society‚ Boucher had access to the most up–to–date information on her disease‚ its treatment‚ and its potential complications. And‚ after doing extensive research‚ she was sure of one thing: She wanted to keep her lymph nodes.

Vulvar cancer is one of approximately a dozen cancers including melanoma and breast cancer that frequently require the removal and microscopic examination of nearby lymph nodes. Such “lymph node dissections” are believed necessary because tumors‚ like normal tissues‚ drain into the lymphatic system—a complex network that transports wastes away from the body’s cells. Lymph nodes are the “treatment centers” of this system‚ packed with white blood cells and antibodies that attack foreign invaders and “clean” the lymphatic fluid.

Lymph Nodes and Diagnosis
The presence of cancer in the lymph nodes has long been considered the single most reliable indicator of cancer’s spread‚ allowing physicians to “stage” the cancer and to make informed decisions about its treatment. In order to get this information‚ however‚ surgeons remove numerous lymph nodes‚ drastically changing the structure and function of the lymphatic system in that area of the body.

For patients‚ the impact of these changes is profound.

With fewer lymph nodes in which to drain‚ lymph fluid can “back up” around the body’s cells‚ causing painful swelling (lymphedema)‚ inhibiting the flow of blood‚ and providing a medium for infections. Research indicates that up to 50% of breast cancer patients experience some degree of lymphedema in the arm nearest their surgery‚ often for decades. Up to 30% of patients with vulvar cancer develop recurrent lymphedema of the legs‚ as do approximately 25% of patients with penile or prostate cancer who have undergone lymph node dissection (removal of lymph nodes close to the site).

“No one told me anything about lymphedema before my surgery‚” recalls Jackie Young‚ PhD‚ a specialist in women’s studies who underwent an axillary node dissection during surgery for breast cancer. “Or if they did‚ I had so much ´emotional noise´ around me that I didn´t hear it. But when it’s over‚ then they start telling you all sorts of things: That you have to be careful. That you can’t trim your cuticles. That you can’t lift things with that arm. That you shouldn’t carry things on that side. And I thought‚‚ ´If it’s that important‚ why didn’t you give me this information before my operation?’”

Up until recently‚ patients like Jackie Young and Susan Boucher had no choice but to sacrifice their lymph nodes and hope for the best. Then came sentinel node biopsy.

Only One Node
Sentinel node biopsy is a relatively new—and still experimental—technique that takes advantage of the fact that most tumors drain first to one particular lymph node. Like a canary in a coal mine’ this sentinel node is the first to be affected by metastatic cells. If the sentinel node is free of cancer‚ nodes further “downstream” presumably will be clean as well and can be left intact. If the node tests positive for cancer‚ neighboring nodes can be removed and examined as usual.

Although the idea of sentinel node biopsy dates to the late ’70s‚ the technique did not become feasible until researchers found a way to actually identify the sentinel node. With the introduction of lymphatic mapping in the ’80s and ’90s‚ medical scientists brought sentinel node biopsy out of the realm of theory and into the realm of practice.

Lymphatic mapping uses a combination of a mildly radioactive tracer and a bright blue dye to follow the path of lymphatic fluid from a tumor to its sentinel node. Surgeons inject the tracer and dye around the tumor and then use a special instrument to trace the radioactivity and identify the “hot spot” where the sentinel node is probably located. A small incision is then made‚ and the surgeon looks for the node that has been stained bright blue by the dye.

Once removed‚ the node is examined under a microscope using a highly sensitive diagnostic technique called immunohistochemistry (IHC)‚ which can detect the presence of even a few individual cancer cells. Sentinel node biopsy was first investigated for penile cancer and melanoma‚ but over the last few years physicians have used the technique with oral cancers‚ gastrointestinal cancers‚ vulvar cancer‚ and‚ most significantly‚ breast cancer. By mid-2001‚ more than 100 surgical teams around the country were using sentinel node biopsy‚ most often for breast cancer. But not everyone is ready to embrace the technique just yet.

“Part of the problem with sentinel node biopsy is that very often it is being done outside of the research protocol‚” says Pond Kelemen‚ MD‚ co–director of the Breast Center at St. Louis University School of Medicine‚ Missouri. “It?s fast becoming the standard of care not by research or scientific methods‚ but by public demand.”

Medical history is full of object lessons on the dangers of accepting new treatments without adequate evidence.

“The fundamental approach in medicine is to be intellectually conservative‚” says Benjamin O. Anderson‚ MD‚ director‚ Breast Health Center‚ University of Washington and the Fred Hutchinson Cancer Research Center‚ Seattle‚ Washington. “You assume that a new treatment doesn’t work until it’s proven that it does. That is the scientific method.”

Collecting the Data on Sentinel Node
As promising as sentinel node biopsy might be‚ long–term data on its benefits are still lacking. Existing research indicates that the accuracy of the technique depends heavily on the experience of the practitioner. Surgeons with relatively little sentinel node experience are more likely to have difficulty finding the sentinel node.

In addition‚ there is some evidence that preoperative chemotherapy can increase the likelihood of negative results in a sentinel node biopsy. Findings such as these worry some oncologists‚ who feel that‚ for the moment at least‚ sentinel node biopsy might best be conducted within the controlled conditions of a clinical trial.

“If you’re going to have a sentinel node performed‚ you have to have it done by someone who knows what they’re doing‚” says Dr. Kelemen. “Experience is very‚ very important. The more experience you have doing the procedure‚ the more accurate the procedure is.”

For patients‚ sentinel node biopsy remains a source of tremendous hope and reassurance. Boucher‚ for one‚ will always regret that her oncology team was unwilling to forego complete lymph node dissection. After weeks of pressing for sentinel node biopsy‚ Boucher finally acquiesced to their concerns—with the caveat that she would become part of a clinical trial in which patients were to receive both a sentinel node biopsy and a complete dissection.

The result? A completely clean slate. All of her nodes were negative.

Today‚ some five years after her surgery‚ Boucher continues to experience intermittent bouts of lymphedema.

“Once lymphedema begins‚ you are never completely symptom free. For me‚ having cancer wasn’t the worst thing that could happen to me. As a nurse‚ I knew enough and could control enough to know my outcome would be good‚” she says. “Now that the treatment is over‚ I don’t get up every day and think‚ ‘I had cancer.’ But then the lymphedema comes back‚ and all of a sudden‚ it’s‚ ‘Oh yeah‚ I had it.´”

On good days‚ Boucher takes comfort in the fact that the operation confirmed her cancer had not spread‚ and that she could take part in a clinical trial on sentinel node biopsy that now offers a choice for others. “It provided information that will make sentinel node biopsy an option for other women with vulvar cancer‚” she says with some satisfaction.

On bad days‚ she still gets angry.

“Intellectually‚ I can understand why this procedure was necessary for me‚ but from a very personal‚ emotional perspective I’m still frustrated‚” she notes ruefully. “I may get it‚ but I don't like it.”