Nodal exams key in managing melanoma

December 1, 2005

In 2005, one in 62 Americans has a lifetime risk of developing invasive melanoma — a 2,000 percent increase since 1930.

National report - New cases of melanoma in the United States are expected to increase 10 percent from 2004 to 2005, according to the American Academy of Dermatology.

And while the AAD reports that 83 percent of melanomas are diagnosed in the localized stage, the chances of developing invasive melanoma continue to climb, as well. In 2005, one in 62 Americans has a lifetime risk of developing invasive melanoma - a 2,000 percent increase since 1930, according to AAD.

"We realize melanoma rates are rising faster than for any other cancer in the U.S.," says Darrell S. Rigel, M.D., clinical professor of dermatology at New York University, New York. "A lot of that increase is in early melanoma, but people cannot forget that the number of thick melanomas is increasing, despite everything that we are doing in public education."

While treatment for early melanoma, defined as 1 mm thick or less, is straightforward excision and possible sentinel node biopsy (SNB), advanced melanoma treatment is another story, with unknowns and controversy.

"Dermatologists need to know the latest in advanced melanoma treatment because we often are the first-line counselors with our patients," Dr. Rigel says. "We also play a big part in treating melanoma and preventing recurrence. We cannot forget that once people have had one melanoma, their chance of having a second melanoma is about 5 percent - about one in 20. Our job is to follow them closely."

The most important thing that dermatologists can do initially for at-risk patients and those who have had melanoma is have patients come in for regular clinical examinations, which should include lymph nodal exams and referrals for necessary biopsies.

"As far as the remaining part of the management, typically you work as a team with a surgeon and medical oncologist to try and deal with these issues," Dr. Rigel says.

Advances in knowledge

Perhaps the biggest development in advanced melanoma diagnosis has been in the area of SNB.

"The SNB is typically used for staging in patients with advanced melanoma," Dr. Rigel says. "If that node is positive, the remaining nodes are often removed in that nodal group, but there are some studies that suggest that may not be necessary because the chance of the remaining nodes being positive is less than 4 percent. If the node is negative, then typically no further surgery is required. Patients who are node positive can be considered for additional therapy."

While physicians and researchers have traditionally looked at node histology under hematoxylin and eosin (H&E) stains, researchers are investigating the use of polymerase chain reaction (PCR) stains to identify micrometastases of melanoma.

"The PCR technique is much more sensitive in finding small amounts of metastases in lymph nodes and there are a number of cases that are being followed now that are H&E negative but PCR positive. It could be that as many as 10 percent or more of all the SNBs being done," Dr. Rigel says. "The challenge that we face is determining what that means. Are people who are PCR positive but H&E negative at increased risk for metastatic disease and other issues related to melanoma? Those studies are ongoing."

Dermatologists should have better answers in the next year or so, according to Dr. Rigel.

Dr. Rigel works with oncologists who order both staining methods, and, at this point, he and his colleagues are treating patients who are PCR positive and H&E negative as if they are SNB negative.

The next controversy with SNB, he says, is what do physicians do when patients have positive sentinel nodes?

"The traditional thinking is that, with a positive sentinel node, you take out the rest of the nodes in that group, but there are some studies coming out now suggesting that might not be as critical, because when you remove the sentinel node the chances are slim that the others are positive," Dr. Rigel says.

Another big question is how to best counsel patients about advanced melanoma treatment.